11da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 21da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * linux/mm/swapfile.c 31da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 41da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 51da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie 61da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 71da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 81da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mm.h> 91da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/hugetlb.h> 101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mman.h> 111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/slab.h> 121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/kernel_stat.h> 131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/swap.h> 141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/vmalloc.h> 151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/pagemap.h> 161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/namei.h> 17072441e21ddcd1140606b7d4ef6eab579a86b0b3Hugh Dickins#include <linux/shmem_fs.h> 181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/blkdev.h> 1920137a490f397d9c01fc9fadd83a8d198bda4477Hugh Dickins#include <linux/random.h> 201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/writeback.h> 211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/proc_fs.h> 221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/seq_file.h> 231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/init.h> 245ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins#include <linux/ksm.h> 251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/rmap.h> 261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/security.h> 271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/backing-dev.h> 28fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar#include <linux/mutex.h> 29c59ede7b78db329949d9cdcd7064e22d357560efRandy.Dunlap#include <linux/capability.h> 301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/syscalls.h> 318a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh#include <linux/memcontrol.h> 3266d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers#include <linux/poll.h> 3372788c385604523422592249c19cba0187021e9bDavid Rientjes#include <linux/oom.h> 341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <asm/pgtable.h> 361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <asm/tlbflush.h> 371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/swapops.h> 3827a7faa0779dd13729196c1a818c294f44bbd1eeKAMEZAWA Hiroyuki#include <linux/page_cgroup.h> 391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 40570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsstatic bool swap_count_continued(struct swap_info_struct *, pgoff_t, 41570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins unsigned char); 42570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsstatic void free_swap_count_continuations(struct swap_info_struct *); 43d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhornstatic sector_t map_swap_entry(swp_entry_t, struct block_device**); 44570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 457c363b8c6536f26934172d3c46f0bbec01a97c61Adrian Bunkstatic DEFINE_SPINLOCK(swap_lock); 467c363b8c6536f26934172d3c46f0bbec01a97c61Adrian Bunkstatic unsigned int nr_swapfiles; 47b962716b459505a8d83aea313fea0abe76749f42Hugh Dickinslong nr_swap_pages; 481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldslong total_swap_pages; 4978ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickinsstatic int least_priority; 501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic const char Bad_file[] = "Bad swap file entry "; 521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic const char Unused_file[] = "Unused swap file entry "; 531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic const char Bad_offset[] = "Bad swap offset entry "; 541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic const char Unused_offset[] = "Unused swap offset entry "; 551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 567c363b8c6536f26934172d3c46f0bbec01a97c61Adrian Bunkstatic struct swap_list_t swap_list = {-1, -1}; 571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 58efa90a981bbc891efad96db2a75b5487e00852caHugh Dickinsstatic struct swap_info_struct *swap_info[MAX_SWAPFILES]; 591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 60fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnarstatic DEFINE_MUTEX(swapon_mutex); 611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 6266d7dd518ae413a383ab2c6c263cc30617329842Kay Sieversstatic DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait); 6366d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers/* Activity counter to indicate that a swapon or swapoff has occurred */ 6466d7dd518ae413a383ab2c6c263cc30617329842Kay Sieversstatic atomic_t proc_poll_event = ATOMIC_INIT(0); 6566d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 668d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickinsstatic inline unsigned char swap_count(unsigned char ent) 67355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki{ 68570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return ent & ~SWAP_HAS_CACHE; /* may include SWAP_HAS_CONT flag */ 69355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki} 70355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 71efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins/* returns 1 if swap entry is freed */ 72c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyukistatic int 73c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki__try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset) 74c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki{ 75efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins swp_entry_t entry = swp_entry(si->type, offset); 76c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki struct page *page; 77c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki int ret = 0; 78c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki 79c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki page = find_get_page(&swapper_space, entry.val); 80c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki if (!page) 81c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki return 0; 82c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki /* 83c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki * This function is called from scan_swap_map() and it's called 84c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki * by vmscan.c at reclaiming pages. So, we hold a lock on a page, here. 85c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki * We have to use trylock for avoiding deadlock. This is a special 86c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki * case and you should use try_to_free_swap() with explicit lock_page() 87c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki * in usual operations. 88c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki */ 89c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki if (trylock_page(page)) { 90c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki ret = try_to_free_swap(page); 91c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki unlock_page(page); 92c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki } 93c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki page_cache_release(page); 94c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki return ret; 95c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki} 96355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 986a6ba83175c029c7820765bae44692266b29e67aHugh Dickins * swapon tell device that all the old swap contents can be discarded, 996a6ba83175c029c7820765bae44692266b29e67aHugh Dickins * to allow the swap device to optimize its wear-levelling. 1006a6ba83175c029c7820765bae44692266b29e67aHugh Dickins */ 1016a6ba83175c029c7820765bae44692266b29e67aHugh Dickinsstatic int discard_swap(struct swap_info_struct *si) 1026a6ba83175c029c7820765bae44692266b29e67aHugh Dickins{ 1036a6ba83175c029c7820765bae44692266b29e67aHugh Dickins struct swap_extent *se; 1049625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins sector_t start_block; 1059625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins sector_t nr_blocks; 1066a6ba83175c029c7820765bae44692266b29e67aHugh Dickins int err = 0; 1076a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 1089625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins /* Do not discard the swap header page! */ 1099625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se = &si->first_swap_extent; 1109625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); 1119625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); 1129625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins if (nr_blocks) { 1139625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins err = blkdev_issue_discard(si->bdev, start_block, 114dd3932eddf428571762596e17b65f5dc92ca361bChristoph Hellwig nr_blocks, GFP_KERNEL, 0); 1159625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins if (err) 1169625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins return err; 1179625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins cond_resched(); 1189625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins } 1196a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 1209625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins list_for_each_entry(se, &si->first_swap_extent.list, list) { 1219625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins start_block = se->start_block << (PAGE_SHIFT - 9); 1229625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9); 1236a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 1246a6ba83175c029c7820765bae44692266b29e67aHugh Dickins err = blkdev_issue_discard(si->bdev, start_block, 125dd3932eddf428571762596e17b65f5dc92ca361bChristoph Hellwig nr_blocks, GFP_KERNEL, 0); 1266a6ba83175c029c7820765bae44692266b29e67aHugh Dickins if (err) 1276a6ba83175c029c7820765bae44692266b29e67aHugh Dickins break; 1286a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 1296a6ba83175c029c7820765bae44692266b29e67aHugh Dickins cond_resched(); 1306a6ba83175c029c7820765bae44692266b29e67aHugh Dickins } 1316a6ba83175c029c7820765bae44692266b29e67aHugh Dickins return err; /* That will often be -EOPNOTSUPP */ 1326a6ba83175c029c7820765bae44692266b29e67aHugh Dickins} 1336a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 1347992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins/* 1357992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * swap allocation tell device that a cluster of swap can now be discarded, 1367992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * to allow the swap device to optimize its wear-levelling. 1377992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 1387992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickinsstatic void discard_swap_cluster(struct swap_info_struct *si, 1397992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins pgoff_t start_page, pgoff_t nr_pages) 1407992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins{ 1417992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins struct swap_extent *se = si->curr_swap_extent; 1427992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins int found_extent = 0; 1437992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1447992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins while (nr_pages) { 1457992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins struct list_head *lh; 1467992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1477992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (se->start_page <= start_page && 1487992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins start_page < se->start_page + se->nr_pages) { 1497992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins pgoff_t offset = start_page - se->start_page; 1507992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins sector_t start_block = se->start_block + offset; 151858a29900ea2d639759e697be901a60b759cdcfbHugh Dickins sector_t nr_blocks = se->nr_pages - offset; 1527992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1537992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (nr_blocks > nr_pages) 1547992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins nr_blocks = nr_pages; 1557992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins start_page += nr_blocks; 1567992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins nr_pages -= nr_blocks; 1577992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1587992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (!found_extent++) 1597992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->curr_swap_extent = se; 1607992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1617992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins start_block <<= PAGE_SHIFT - 9; 1627992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins nr_blocks <<= PAGE_SHIFT - 9; 1637992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (blkdev_issue_discard(si->bdev, start_block, 164dd3932eddf428571762596e17b65f5dc92ca361bChristoph Hellwig nr_blocks, GFP_NOIO, 0)) 1657992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins break; 1667992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } 1677992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1687992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins lh = se->list.next; 1697992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins se = list_entry(lh, struct swap_extent, list); 1707992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } 1717992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins} 1727992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 1737992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickinsstatic int wait_for_discard(void *word) 1747992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins{ 1757992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins schedule(); 1767992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins return 0; 1777992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins} 1787992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 179048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins#define SWAPFILE_CLUSTER 256 180048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins#define LATENCY_LIMIT 256 181048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins 18224b8ff7c27d9e975540656e377de44a2a181a01fCesar Eduardo Barrosstatic unsigned long scan_swap_map(struct swap_info_struct *si, 18324b8ff7c27d9e975540656e377de44a2a181a01fCesar Eduardo Barros unsigned char usage) 1841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 185ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins unsigned long offset; 186c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins unsigned long scan_base; 1877992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins unsigned long last_in_cluster = 0; 188048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins int latency_ration = LATENCY_LIMIT; 1897992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins int found_free_cluster = 0; 1907dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 191886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins /* 1927dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * We try to cluster swap pages by allocating them sequentially 1937dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * in swap. Once we've allocated SWAPFILE_CLUSTER pages this 1947dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * way, however, we resort to first-free allocation, starting 1957dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * a new cluster. This prevents us from scattering swap pages 1967dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * all over the entire swap partition, so that we reduce 1977dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * overall disk seek times between swap pages. -- sct 1987dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins * But we do now try to find an empty cluster. -Andrea 199c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * And we let swap pages go all over an SSD partition. Hugh 2007dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins */ 2017dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 20252b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins si->flags += SWP_SCANNING; 203c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins scan_base = offset = si->cluster_next; 204ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins 205ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (unlikely(!si->cluster_nr--)) { 206ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) { 207ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->cluster_nr = SWAPFILE_CLUSTER - 1; 208ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins goto checks; 209ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins } 2107992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (si->flags & SWP_DISCARDABLE) { 2117992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins /* 2127992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * Start range check on racing allocations, in case 2137992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * they overlap the cluster we eventually decide on 2147992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * (we scan without swap_lock to allow preemption). 2157992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * It's hardly conceivable that cluster_nr could be 2167992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * wrapped during our scan, but don't depend on it. 2177992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 2187992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (si->lowest_alloc) 2197992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins goto checks; 2207992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->lowest_alloc = si->max; 2217992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->highest_alloc = 0; 2227992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } 2235d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 2247dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 225c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins /* 226c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * If seek is expensive, start searching for new cluster from 227c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * start of partition, to minimize the span of allocated swap. 228c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * But if seek is cheap, search from our current position, so 229c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * that swap is allocated from all over the partition: if the 230c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * Flash Translation Layer only remaps within limited zones, 231c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins * we don't want to wear out the first zone too quickly. 232c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins */ 233c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins if (!(si->flags & SWP_SOLIDSTATE)) 234c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins scan_base = offset = si->lowest_bit; 2357dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins last_in_cluster = offset + SWAPFILE_CLUSTER - 1; 2367dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 2377dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins /* Locate the first empty (unaligned) cluster */ 2387dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins for (; last_in_cluster <= si->highest_bit; offset++) { 2391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (si->swap_map[offset]) 2407dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins last_in_cluster = offset + SWAPFILE_CLUSTER; 2417dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins else if (offset == last_in_cluster) { 2425d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 243ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins offset -= SWAPFILE_CLUSTER - 1; 244ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->cluster_next = offset; 245ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->cluster_nr = SWAPFILE_CLUSTER - 1; 2467992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins found_free_cluster = 1; 247ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins goto checks; 2481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 249048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins if (unlikely(--latency_ration < 0)) { 250048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins cond_resched(); 251048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins latency_ration = LATENCY_LIMIT; 252048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins } 2537dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins } 254ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins 255ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins offset = si->lowest_bit; 256c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins last_in_cluster = offset + SWAPFILE_CLUSTER - 1; 257c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins 258c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins /* Locate the first empty (unaligned) cluster */ 259c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins for (; last_in_cluster < scan_base; offset++) { 260c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins if (si->swap_map[offset]) 261c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins last_in_cluster = offset + SWAPFILE_CLUSTER; 262c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins else if (offset == last_in_cluster) { 263c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins spin_lock(&swap_lock); 264c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins offset -= SWAPFILE_CLUSTER - 1; 265c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins si->cluster_next = offset; 266c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins si->cluster_nr = SWAPFILE_CLUSTER - 1; 267c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins found_free_cluster = 1; 268c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins goto checks; 269c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 270c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins if (unlikely(--latency_ration < 0)) { 271c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins cond_resched(); 272c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins latency_ration = LATENCY_LIMIT; 273c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 274c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 275c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins 276c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins offset = scan_base; 2775d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 278ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->cluster_nr = SWAPFILE_CLUSTER - 1; 2797992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->lowest_alloc = 0; 2801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2817dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 282ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickinschecks: 283ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (!(si->flags & SWP_WRITEOK)) 28452b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins goto no_page; 2857dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins if (!si->highest_bit) 2867dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins goto no_page; 287ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (offset > si->highest_bit) 288c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins scan_base = offset = si->lowest_bit; 289c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki 290b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins /* reuse swap entry of cache-only swap if not busy. */ 291b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { 292c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki int swap_was_freed; 293c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki spin_unlock(&swap_lock); 294c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki swap_was_freed = __try_to_reclaim_swap(si, offset); 295c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki spin_lock(&swap_lock); 296c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki /* entry was freed successfully, try to use this again */ 297c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki if (swap_was_freed) 298c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki goto checks; 299c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki goto scan; /* check next one */ 300c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki } 301c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki 302ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (si->swap_map[offset]) 303ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins goto scan; 304ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins 305ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (offset == si->lowest_bit) 306ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->lowest_bit++; 307ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (offset == si->highest_bit) 308ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->highest_bit--; 309ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->inuse_pages++; 310ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins if (si->inuse_pages == si->pages) { 311ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->lowest_bit = si->max; 312ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->highest_bit = 0; 3131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 314253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins si->swap_map[offset] = usage; 315ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->cluster_next = offset + 1; 316ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins si->flags -= SWP_SCANNING; 3177992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 3187992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (si->lowest_alloc) { 3197992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins /* 3207992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * Only set when SWP_DISCARDABLE, and there's a scan 3217992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * for a free cluster in progress or just completed. 3227992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 3237992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (found_free_cluster) { 3247992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins /* 3257992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * To optimize wear-levelling, discard the 3267992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * old data of the cluster, taking care not to 3277992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * discard any of its pages that have already 3287992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * been allocated by racing tasks (offset has 3297992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * already stepped over any at the beginning). 3307992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 3317992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (offset < si->highest_alloc && 3327992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->lowest_alloc <= last_in_cluster) 3337992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins last_in_cluster = si->lowest_alloc - 1; 3347992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->flags |= SWP_DISCARDING; 3357992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins spin_unlock(&swap_lock); 3367992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 3377992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (offset < last_in_cluster) 3387992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins discard_swap_cluster(si, offset, 3397992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins last_in_cluster - offset + 1); 3407992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 3417992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins spin_lock(&swap_lock); 3427992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->lowest_alloc = 0; 3437992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->flags &= ~SWP_DISCARDING; 3447992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 3457992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins smp_mb(); /* wake_up_bit advises this */ 3467992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins wake_up_bit(&si->flags, ilog2(SWP_DISCARDING)); 3477992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins 3487992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } else if (si->flags & SWP_DISCARDING) { 3497992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins /* 3507992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * Delay using pages allocated by racing tasks 3517992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * until the whole discard has been issued. We 3527992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * could defer that delay until swap_writepage, 3537992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * but it's easier to keep this self-contained. 3547992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 3557992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins spin_unlock(&swap_lock); 3567992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins wait_on_bit(&si->flags, ilog2(SWP_DISCARDING), 3577992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins wait_for_discard, TASK_UNINTERRUPTIBLE); 3587992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins spin_lock(&swap_lock); 3597992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } else { 3607992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins /* 3617992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * Note pages allocated by racing tasks while 3627992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * scan for a free cluster is in progress, so 3637992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins * that its final discard can exclude them. 3647992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins */ 3657992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (offset < si->lowest_alloc) 3667992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->lowest_alloc = offset; 3677992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins if (offset > si->highest_alloc) 3687992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins si->highest_alloc = offset; 3697992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } 3707992fde72ce06c73280a1939b7a1e903bc95ef85Hugh Dickins } 371ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickins return offset; 3727dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 373ebebbbe904634b0ca1c674457b399f68db5e05b1Hugh Dickinsscan: 3745d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 3757dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins while (++offset <= si->highest_bit) { 37652b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins if (!si->swap_map[offset]) { 3775d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 37852b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins goto checks; 37952b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins } 380c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { 381c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki spin_lock(&swap_lock); 382c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki goto checks; 383c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki } 384048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins if (unlikely(--latency_ration < 0)) { 385048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins cond_resched(); 386048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins latency_ration = LATENCY_LIMIT; 387048c27fd72816b44e096997d1c6901c3abbfd45bHugh Dickins } 3887dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins } 389c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins offset = si->lowest_bit; 390c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins while (++offset < scan_base) { 391c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins if (!si->swap_map[offset]) { 392c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins spin_lock(&swap_lock); 393c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins goto checks; 394c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 395c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { 396c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki spin_lock(&swap_lock); 397c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki goto checks; 398c9e444103b5e7a5a3519f9913f59767f92e33bafKAMEZAWA Hiroyuki } 399c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins if (unlikely(--latency_ration < 0)) { 400c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins cond_resched(); 401c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins latency_ration = LATENCY_LIMIT; 402c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 403c60aa176c6de82703f064082b909496fc4fee956Hugh Dickins } 4045d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 4057dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickins 4067dfad4183bf9cd92f977caa3c12cc74f0eefc0e6Hugh Dickinsno_page: 40752b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins si->flags -= SWP_SCANNING; 4081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 4091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 4101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 4111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsswp_entry_t get_swap_page(void) 4121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 413fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins struct swap_info_struct *si; 414fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins pgoff_t offset; 415fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins int type, next; 416fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins int wrapped = 0; 4171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 4185d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 4191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (nr_swap_pages <= 0) 420fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins goto noswap; 421fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins nr_swap_pages--; 422fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins 423fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { 424efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si = swap_info[type]; 425fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins next = si->next; 426fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins if (next < 0 || 427efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins (!wrapped && si->prio != swap_info[next]->prio)) { 428fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins next = swap_list.head; 429fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins wrapped++; 4301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 431fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins 432fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins if (!si->highest_bit) 433fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins continue; 434fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins if (!(si->flags & SWP_WRITEOK)) 435fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins continue; 436fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins 437fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins swap_list.next = next; 438355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki /* This is called for allocating swap entry for cache */ 439253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins offset = scan_swap_map(si, SWAP_HAS_CACHE); 4405d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins if (offset) { 4415d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 442fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins return swp_entry(type, offset); 4435d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins } 444fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins next = swap_list.next; 4451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 446fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins 447fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins nr_swap_pages++; 448fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickinsnoswap: 4495d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 450fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins return (swp_entry_t) {0}; 4511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 4521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 453910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins/* The only caller of this function is now susupend routine */ 454910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickinsswp_entry_t get_swap_page_of_type(int type) 455910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins{ 456910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins struct swap_info_struct *si; 457910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins pgoff_t offset; 458910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins 459910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins spin_lock(&swap_lock); 460910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins si = swap_info[type]; 461910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins if (si && (si->flags & SWP_WRITEOK)) { 462910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins nr_swap_pages--; 463910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins /* This is called for allocating swap entry, not cache */ 464910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins offset = scan_swap_map(si, 1); 465910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins if (offset) { 466910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins spin_unlock(&swap_lock); 467910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins return swp_entry(type, offset); 468910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins } 469910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins nr_swap_pages++; 470910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins } 471910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins spin_unlock(&swap_lock); 472910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins return (swp_entry_t) {0}; 473910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins} 474910321ea817a202ff70fac666e37e2c8e2f88823Hugh Dickins 47573c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickinsstatic struct swap_info_struct *swap_info_get(swp_entry_t entry) 4761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 47773c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct swap_info_struct *p; 4781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long offset, type; 4791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 4801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!entry.val) 4811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 4821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds type = swp_type(entry); 4831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (type >= nr_swapfiles) 4841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_nofile; 485efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p = swap_info[type]; 4861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!(p->flags & SWP_USED)) 4871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_device; 4881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds offset = swp_offset(entry); 4891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (offset >= p->max) 4901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_offset; 4911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!p->swap_map[offset]) 4921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_free; 4935d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 4941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return p; 4951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 4961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_free: 4971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); 4981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 4991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_offset: 5001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); 5011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 5021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_device: 5031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); 5041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 5051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_nofile: 5061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); 5071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout: 5081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return NULL; 509886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins} 5101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 5118d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickinsstatic unsigned char swap_entry_free(struct swap_info_struct *p, 5128d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins swp_entry_t entry, unsigned char usage) 5131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 514253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins unsigned long offset = swp_offset(entry); 5158d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char count; 5168d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char has_cache; 517355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 518253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins count = p->swap_map[offset]; 519253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins has_cache = count & SWAP_HAS_CACHE; 520253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins count &= ~SWAP_HAS_CACHE; 521355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 522253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (usage == SWAP_HAS_CACHE) { 523355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki VM_BUG_ON(!has_cache); 524253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins has_cache = 0; 525aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins } else if (count == SWAP_MAP_SHMEM) { 526aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins /* 527aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins * Or we could insist on shmem.c using a special 528aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins * swap_shmem_free() and free_shmem_swap_and_cache()... 529aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins */ 530aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins count = 0; 531570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) { 532570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (count == COUNT_CONTINUED) { 533570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (swap_count_continued(p, offset, count)) 534570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = SWAP_MAP_MAX | COUNT_CONTINUED; 535570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins else 536570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = SWAP_MAP_MAX; 537570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } else 538570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count--; 539570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 540253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 541253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (!count) 542253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins mem_cgroup_uncharge_swap(entry); 543253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 544253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins usage = count | has_cache; 545253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins p->swap_map[offset] = usage; 546355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 547355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki /* free if no reference */ 548253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (!usage) { 549b3a27d0529c6e5206f1b60f60263e3ecfd0d77cbNitin Gupta struct gendisk *disk = p->bdev->bd_disk; 550355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (offset < p->lowest_bit) 551355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki p->lowest_bit = offset; 552355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (offset > p->highest_bit) 553355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki p->highest_bit = offset; 554efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (swap_list.next >= 0 && 555efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p->prio > swap_info[swap_list.next]->prio) 556efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins swap_list.next = p->type; 557355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki nr_swap_pages++; 558355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki p->inuse_pages--; 559b3a27d0529c6e5206f1b60f60263e3ecfd0d77cbNitin Gupta if ((p->flags & SWP_BLKDEV) && 560b3a27d0529c6e5206f1b60f60263e3ecfd0d77cbNitin Gupta disk->fops->swap_slot_free_notify) 561b3a27d0529c6e5206f1b60f60263e3ecfd0d77cbNitin Gupta disk->fops->swap_slot_free_notify(p->bdev, offset); 5621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 563253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 564253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins return usage; 5651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 5661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 5671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 5681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Caller has made sure that the swapdevice corresponding to entry 5691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * is still around or has not been recycled. 5701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 5711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsvoid swap_free(swp_entry_t entry) 5721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 57373c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct swap_info_struct *p; 5741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 5751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p = swap_info_get(entry); 5761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (p) { 577253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins swap_entry_free(p, entry, 1); 5785d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 5791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 5801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 5811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 5821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 583cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki * Called after dropping swapcache to decrease refcnt to swap entries. 584cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki */ 585cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyukivoid swapcache_free(swp_entry_t entry, struct page *page) 586cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki{ 587355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki struct swap_info_struct *p; 5888d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char count; 589355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 590355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki p = swap_info_get(entry); 591355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (p) { 592253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins count = swap_entry_free(p, entry, SWAP_HAS_CACHE); 593253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (page) 594253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins mem_cgroup_uncharge_swapcache(page, entry, count != 0); 595355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki spin_unlock(&swap_lock); 596355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki } 597cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki} 598cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki 599cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki/* 600c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins * How many references to page are currently swapped out? 601570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * This does not give an exact answer when swap count is continued, 602570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * but does include the high COUNT_CONTINUED flag to allow for that. 6031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 604c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickinsstatic inline int page_swapcount(struct page *page) 6051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 606c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins int count = 0; 607c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins struct swap_info_struct *p; 6081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry; 6091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 6104c21e2f2441dc5fbb957b030333f5a3f2d02dea7Hugh Dickins entry.val = page_private(page); 6111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p = swap_info_get(entry); 6121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (p) { 613355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki count = swap_count(p->swap_map[swp_offset(entry)]); 6145d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 6151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 616c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins return count; 6171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 6181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 6191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 6207b1fe59793e61f826bef053107b57b23954833bbHugh Dickins * We can write to an anon page without COW if there are no other references 6217b1fe59793e61f826bef053107b57b23954833bbHugh Dickins * to it. And as a side-effect, free up its swap: because the old content 6227b1fe59793e61f826bef053107b57b23954833bbHugh Dickins * on disk will never be read, and seeking back there to write new content 6237b1fe59793e61f826bef053107b57b23954833bbHugh Dickins * later would only waste time away from clustering. 6241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 6257b1fe59793e61f826bef053107b57b23954833bbHugh Dickinsint reuse_swap_page(struct page *page) 6261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 627c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins int count; 628c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins 62951726b1222863852c46ca21ed0115b85d1edfd89Hugh Dickins VM_BUG_ON(!PageLocked(page)); 6305ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins if (unlikely(PageKsm(page))) 6315ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins return 0; 632c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins count = page_mapcount(page); 6337b1fe59793e61f826bef053107b57b23954833bbHugh Dickins if (count <= 1 && PageSwapCache(page)) { 634c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins count += page_swapcount(page); 6357b1fe59793e61f826bef053107b57b23954833bbHugh Dickins if (count == 1 && !PageWriteback(page)) { 6367b1fe59793e61f826bef053107b57b23954833bbHugh Dickins delete_from_swap_cache(page); 6377b1fe59793e61f826bef053107b57b23954833bbHugh Dickins SetPageDirty(page); 6387b1fe59793e61f826bef053107b57b23954833bbHugh Dickins } 6397b1fe59793e61f826bef053107b57b23954833bbHugh Dickins } 6405ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins return count <= 1; 6411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 6421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 6431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 644a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins * If swap is getting full, or if there are no more mappings of this page, 645a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins * then try_to_free_swap is called to free its swap space. 6461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 647a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickinsint try_to_free_swap(struct page *page) 6481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 64951726b1222863852c46ca21ed0115b85d1edfd89Hugh Dickins VM_BUG_ON(!PageLocked(page)); 6501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 6511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!PageSwapCache(page)) 6521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 6531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (PageWriteback(page)) 6541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 655a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins if (page_swapcount(page)) 6561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 6571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 658b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins /* 659b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * Once hibernation has begun to create its image of memory, 660b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * there's a danger that one of the calls to try_to_free_swap() 661b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * - most probably a call from __try_to_reclaim_swap() while 662b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * hibernation is allocating its own swap pages for the image, 663b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * but conceivably even a call from memory reclaim - will free 664b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * the swap from a page which has already been recorded in the 665b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * image as a clean swapcache page, and then reuse its swap for 666b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * another page of the image. On waking from hibernation, the 667b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * original page might be freed under memory pressure, then 668b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * later read back in from swap, now with the wrong data. 669b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins * 670f90ac3982a78d36f894824636beeef13361d7c59Mel Gorman * Hibration suspends storage while it is writing the image 671f90ac3982a78d36f894824636beeef13361d7c59Mel Gorman * to disk so check that here. 672b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins */ 673f90ac3982a78d36f894824636beeef13361d7c59Mel Gorman if (pm_suspended_storage()) 674b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins return 0; 675b73d7fcecd93dc15eaa3c45c8c587b613f6673c4Hugh Dickins 676a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins delete_from_swap_cache(page); 677a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins SetPageDirty(page); 678a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins return 1; 67968a22394c286a2daf06ee8d65d8835f738faefa5Rik van Riel} 68068a22394c286a2daf06ee8d65d8835f738faefa5Rik van Riel 68168a22394c286a2daf06ee8d65d8835f738faefa5Rik van Riel/* 6821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Free the swap entry like above, but also try to 6831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * free the page cache entry if it is the last user. 6841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 6852509ef26db4699a5d9fa876e90ddfc107afcab84Hugh Dickinsint free_swap_and_cache(swp_entry_t entry) 6861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 6872509ef26db4699a5d9fa876e90ddfc107afcab84Hugh Dickins struct swap_info_struct *p; 6881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct page *page = NULL; 6891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 690a7420aa54dbf699a5a05feba3c859b6baaa3938cAndi Kleen if (non_swap_entry(entry)) 6912509ef26db4699a5d9fa876e90ddfc107afcab84Hugh Dickins return 1; 6920697212a411c1dae03c27845f2de2f3adb32c331Christoph Lameter 6931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p = swap_info_get(entry); 6941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (p) { 695253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (swap_entry_free(p, entry, 1) == SWAP_HAS_CACHE) { 69693fac7041f082297b93655a0e49f659cd7520e40Nick Piggin page = find_get_page(&swapper_space, entry.val); 6978413ac9d8c9a1366a4f57880723126cd24e5a5c3Nick Piggin if (page && !trylock_page(page)) { 69893fac7041f082297b93655a0e49f659cd7520e40Nick Piggin page_cache_release(page); 69993fac7041f082297b93655a0e49f659cd7520e40Nick Piggin page = NULL; 70093fac7041f082297b93655a0e49f659cd7520e40Nick Piggin } 70193fac7041f082297b93655a0e49f659cd7520e40Nick Piggin } 7025d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 7031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 7041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (page) { 705a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins /* 706a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins * Not mapped elsewhere, or swap space full? Free it! 707a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins * Also recheck PageSwapCache now page is locked (above). 708a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins */ 70993fac7041f082297b93655a0e49f659cd7520e40Nick Piggin if (PageSwapCache(page) && !PageWriteback(page) && 710a2c43eed8334e878702fca713b212ae2a11d84b9Hugh Dickins (!page_mapped(page) || vm_swap_full())) { 7111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds delete_from_swap_cache(page); 7121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds SetPageDirty(page); 7131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 7141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unlock_page(page); 7151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_cache_release(page); 7161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 7172509ef26db4699a5d9fa876e90ddfc107afcab84Hugh Dickins return p != NULL; 7181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 7191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 720024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura#ifdef CONFIG_CGROUP_MEM_RES_CTLR 721024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura/** 722024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * mem_cgroup_count_swap_user - count the user of a swap entry 723024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * @ent: the swap entry to be checked 724024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * @pagep: the pointer for the swap cache page of the entry to be stored 725024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * 726024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * Returns the number of the user of the swap entry. The number is valid only 727024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * for swaps of anonymous pages. 728024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * If the entry is found on swap cache, the page is stored to pagep with 729024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura * refcount of it being incremented. 730024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura */ 731024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimuraint mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) 732024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura{ 733024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura struct page *page; 734024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura struct swap_info_struct *p; 735024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura int count = 0; 736024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura 737024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura page = find_get_page(&swapper_space, ent.val); 738024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura if (page) 739024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura count += page_mapcount(page); 740024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura p = swap_info_get(ent); 741024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura if (p) { 742024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura count += swap_count(p->swap_map[swp_offset(ent)]); 743024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura spin_unlock(&swap_lock); 744024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura } 745024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura 746024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura *pagep = page; 747024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura return count; 748024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura} 749024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura#endif 750024914477e15ef8b17f271ec47f1bb8a589f0806Daisuke Nishimura 751b0cb1a19d05b8ea8611a9ef48a17fe417f1832e6Rafael J. Wysocki#ifdef CONFIG_HIBERNATION 752f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki/* 753915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki * Find the swap type that corresponds to given device (if any). 754f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki * 755915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki * @offset - number of the PAGE_SIZE-sized block of the device, starting 756915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki * from 0, in which the swap header is expected to be located. 757915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki * 758915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki * This is needed for the suspend to disk (aka swsusp). 759f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki */ 7607bf236874292fd073c6bdd27f89c3d9e81a79cbcRafael J. Wysockiint swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) 761f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki{ 762915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki struct block_device *bdev = NULL; 763efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins int type; 764f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki 765915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (device) 766915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki bdev = bdget(device); 767915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki 768f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki spin_lock(&swap_lock); 769efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = 0; type < nr_swapfiles; type++) { 770efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *sis = swap_info[type]; 771f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki 772915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (!(sis->flags & SWP_WRITEOK)) 773f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki continue; 774b6b5bce3571e496504a89ee575d32101e0a98b93Rafael J. Wysocki 775915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (!bdev) { 7767bf236874292fd073c6bdd27f89c3d9e81a79cbcRafael J. Wysocki if (bdev_p) 777dddac6a7b445de95515f64fdf82fe5dc36c02f26Alan Jenkins *bdev_p = bdgrab(sis->bdev); 7787bf236874292fd073c6bdd27f89c3d9e81a79cbcRafael J. Wysocki 7796e1819d615f24ce0726a7d0bd3dd0152d7b21654Rafael J. Wysocki spin_unlock(&swap_lock); 780efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins return type; 7816e1819d615f24ce0726a7d0bd3dd0152d7b21654Rafael J. Wysocki } 782915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (bdev == sis->bdev) { 7839625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins struct swap_extent *se = &sis->first_swap_extent; 784915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki 785915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (se->start_block == offset) { 7867bf236874292fd073c6bdd27f89c3d9e81a79cbcRafael J. Wysocki if (bdev_p) 787dddac6a7b445de95515f64fdf82fe5dc36c02f26Alan Jenkins *bdev_p = bdgrab(sis->bdev); 7887bf236874292fd073c6bdd27f89c3d9e81a79cbcRafael J. Wysocki 789915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki spin_unlock(&swap_lock); 790915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki bdput(bdev); 791efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins return type; 792915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki } 793f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki } 794f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki } 795f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki spin_unlock(&swap_lock); 796915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki if (bdev) 797915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki bdput(bdev); 798915bae9ebe41e52d71ad8b06d50e4ab26189f964Rafael J. Wysocki 799f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki return -ENODEV; 800f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki} 801f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki 802f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki/* 80373c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev 80473c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins * corresponding to given index in swap_info (swap type). 80573c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins */ 80673c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickinssector_t swapdev_block(int type, pgoff_t offset) 80773c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins{ 80873c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct block_device *bdev; 80973c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins 81073c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins if ((unsigned int)type >= nr_swapfiles) 81173c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins return 0; 81273c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins if (!(swap_info[type]->flags & SWP_WRITEOK)) 81373c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins return 0; 814d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn return map_swap_entry(swp_entry(type, offset), &bdev); 81573c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins} 81673c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins 81773c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins/* 818f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki * Return either the total number of swap pages of given type, or the number 819f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki * of free pages of that type (depending on @free) 820f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki * 821f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki * This is needed for software suspend 822f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki */ 823f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysockiunsigned int count_swap_pages(int type, int free) 824f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki{ 825f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki unsigned int n = 0; 826f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki 827efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins spin_lock(&swap_lock); 828efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if ((unsigned int)type < nr_swapfiles) { 829efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *sis = swap_info[type]; 830efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins 831efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (sis->flags & SWP_WRITEOK) { 832efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins n = sis->pages; 833f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki if (free) 834efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins n -= sis->inuse_pages; 835f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki } 836f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki } 837efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins spin_unlock(&swap_lock); 838f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki return n; 839f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki} 84073c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins#endif /* CONFIG_HIBERNATION */ 841f577eb30afdc68233f25d4d82b04102129262365Rafael J. Wysocki 8421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 84372866f6f277ec0ddd6df7a3b6ecdcf59a28de115Hugh Dickins * No need to decide whether this PTE shares the swap entry with others, 84472866f6f277ec0ddd6df7a3b6ecdcf59a28de115Hugh Dickins * just let do_wp_page work it out if a write is requested later - to 84572866f6f277ec0ddd6df7a3b6ecdcf59a28de115Hugh Dickins * force COW, vm_page_prot omits write permission from any private vma. 8461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 847044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickinsstatic int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, 8481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long addr, swp_entry_t entry, struct page *page) 8491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 85072835c86ca15d0126354b73d5f29ce9194931c9bJohannes Weiner struct mem_cgroup *memcg; 851044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins spinlock_t *ptl; 852044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte_t *pte; 853044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins int ret = 1; 854044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins 85572835c86ca15d0126354b73d5f29ce9194931c9bJohannes Weiner if (mem_cgroup_try_charge_swapin(vma->vm_mm, page, 85672835c86ca15d0126354b73d5f29ce9194931c9bJohannes Weiner GFP_KERNEL, &memcg)) { 857044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins ret = -ENOMEM; 85885d9fc89fb0f0703df6444f260187c088a8d59ffKAMEZAWA Hiroyuki goto out_nolock; 85985d9fc89fb0f0703df6444f260187c088a8d59ffKAMEZAWA Hiroyuki } 860044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins 861044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 862044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { 863044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins if (ret > 0) 86472835c86ca15d0126354b73d5f29ce9194931c9bJohannes Weiner mem_cgroup_cancel_charge_swapin(memcg); 865044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins ret = 0; 866044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins goto out; 867044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins } 8688a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh 869b084d4353ff99d824d3bc5a5c2c22c70b1fba722KAMEZAWA Hiroyuki dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 870d559db086ff5be9bcc259e5aa50bf3d881eaf1d1KAMEZAWA Hiroyuki inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 8711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds get_page(page); 8721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_pte_at(vma->vm_mm, addr, pte, 8731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pte_mkold(mk_pte(page, vma->vm_page_prot))); 8741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_add_anon_rmap(page, vma, addr); 87572835c86ca15d0126354b73d5f29ce9194931c9bJohannes Weiner mem_cgroup_commit_charge_swapin(page, memcg); 8761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_free(entry); 8771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 8781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Move the page to the active list so it is not 8791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * immediately swapped out again after swapon. 8801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 8811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds activate_page(page); 882044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickinsout: 883044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte_unmap_unlock(pte, ptl); 88485d9fc89fb0f0703df6444f260187c088a8d59ffKAMEZAWA Hiroyukiout_nolock: 885044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins return ret; 8861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 8871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 8881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, 8891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long addr, unsigned long end, 8901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry, struct page *page) 8911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 8921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pte_t swp_pte = swp_entry_to_pte(entry); 893705e87c0c3c38424f7f30556c85bc20e808d2f59Hugh Dickins pte_t *pte; 8948a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh int ret = 0; 8951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 896044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins /* 897044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * We don't actually need pte lock while scanning for swp_pte: since 898044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * we hold page lock and mmap_sem, swp_pte cannot be inserted into the 899044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * page table while we're scanning; though it could get zapped, and on 900044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * some architectures (e.g. x86_32 with PAE) we might catch a glimpse 901044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * of unmatched parts which look like swp_pte, so unuse_pte must 902044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * recheck under pte lock. Scanning without pte lock lets it be 903044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. 904044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins */ 905044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte = pte_offset_map(pmd, addr); 9061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds do { 9071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 9081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * swapoff spends a _lot_ of time in this loop! 9091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Test inline before going to call unuse_pte. 9101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 9111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (unlikely(pte_same(*pte, swp_pte))) { 912044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte_unmap(pte); 913044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins ret = unuse_pte(vma, pmd, addr, entry, page); 914044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins if (ret) 915044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins goto out; 916044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte = pte_offset_map(pmd, addr); 9171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 9181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 919044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickins pte_unmap(pte - 1); 920044d66c1d2b1c5aa50b4d6d68c21c6c93dd678daHugh Dickinsout: 9218a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh return ret; 9221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 9231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, 9251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long addr, unsigned long end, 9261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry, struct page *page) 9271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 9281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pmd_t *pmd; 9291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long next; 9308a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh int ret; 9311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pmd = pmd_offset(pud, addr); 9331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds do { 9341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds next = pmd_addr_end(addr, end); 9353f04f62f90d46a82dd73027c5fd7a15daed5c33dAndrea Arcangeli if (unlikely(pmd_trans_huge(*pmd))) 9363f04f62f90d46a82dd73027c5fd7a15daed5c33dAndrea Arcangeli continue; 9371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 9381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 9398a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh ret = unuse_pte_range(vma, pmd, addr, next, entry, page); 9408a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh if (ret) 9418a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh return ret; 9421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } while (pmd++, addr = next, addr != end); 9431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 9441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 9451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, 9471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long addr, unsigned long end, 9481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry, struct page *page) 9491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 9501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pud_t *pud; 9511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long next; 9528a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh int ret; 9531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pud = pud_offset(pgd, addr); 9551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds do { 9561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds next = pud_addr_end(addr, end); 9571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (pud_none_or_clear_bad(pud)) 9581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 9598a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh ret = unuse_pmd_range(vma, pud, addr, next, entry, page); 9608a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh if (ret) 9618a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh return ret; 9621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } while (pud++, addr = next, addr != end); 9631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 9641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 9651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int unuse_vma(struct vm_area_struct *vma, 9671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry, struct page *page) 9681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 9691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pgd_t *pgd; 9701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long addr, end, next; 9718a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh int ret; 9721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9733ca7b3c5b64d35fe02c35b5d44c2c58b49499feeHugh Dickins if (page_anon_vma(page)) { 9741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds addr = page_address_in_vma(page, vma); 9751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (addr == -EFAULT) 9761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 9771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds else 9781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds end = addr + PAGE_SIZE; 9791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } else { 9801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds addr = vma->vm_start; 9811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds end = vma->vm_end; 9821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 9831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 9851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds do { 9861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds next = pgd_addr_end(addr, end); 9871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 9881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 9898a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh ret = unuse_pud_range(vma, pgd, addr, next, entry, page); 9908a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh if (ret) 9918a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh return ret; 9921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } while (pgd++, addr = next, addr != end); 9931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 9941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 9951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 9961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int unuse_mm(struct mm_struct *mm, 9971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry, struct page *page) 9981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 9991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct vm_area_struct *vma; 10008a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh int ret = 0; 10011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!down_read_trylock(&mm->mmap_sem)) { 10031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 10047d03431cf98aaed635524024273668bb8cedaddaFernando Luis Vazquez Cao * Activate page so shrink_inactive_list is unlikely to unmap 10057d03431cf98aaed635524024273668bb8cedaddaFernando Luis Vazquez Cao * its ptes while lock is dropped, so swapoff can make progress. 10061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 1007c475a8ab625d567eacf5e30ec35d6d8704558062Hugh Dickins activate_page(page); 10081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unlock_page(page); 10091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds down_read(&mm->mmap_sem); 10101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds lock_page(page); 10111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 10121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds for (vma = mm->mmap; vma; vma = vma->vm_next) { 10138a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) 10141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 10151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 10161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds up_read(&mm->mmap_sem); 10178a9f3ccd24741b50200c3f33d62534c7271f3dfcBalbir Singh return (ret < 0)? ret: 0; 10181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 10191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 10211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Scan swap_map from current position to next entry still in use. 10221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Recycle to start on reaching the end, returning 0 when empty. 10231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10246eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickinsstatic unsigned int find_next_to_unuse(struct swap_info_struct *si, 10256eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickins unsigned int prev) 10261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 10276eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickins unsigned int max = si->max; 10286eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickins unsigned int i = prev; 10298d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char count; 10301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 10325d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * No need for swap_lock here: we're just looking 10331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * for whether an entry is in use, not modifying it; false 10341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * hits are okay, and sys_swapoff() has already prevented new 10355d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * allocations from this area (while holding swap_lock). 10361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds for (;;) { 10381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (++i >= max) { 10391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!prev) { 10401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds i = 0; 10411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 10421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 10431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 10441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * No entries in use at top of swap_map, 10451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * loop back to start and recheck there. 10461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds max = prev + 1; 10481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds prev = 0; 10491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds i = 1; 10501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 10511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds count = si->swap_map[i]; 1052355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (count && swap_count(count) != SWAP_MAP_BAD) 10531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 10541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 10551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return i; 10561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 10571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 10591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * We completely avoid races by reading each swap page in advance, 10601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * and then search for the process using it. All the necessary 10611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * page table adjustments can then be made atomically. 10621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int try_to_unuse(unsigned int type) 10641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1065efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *si = swap_info[type]; 10661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mm_struct *start_mm; 10678d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char *swap_map; 10688d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char swcount; 10691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct page *page; 10701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swp_entry_t entry; 10716eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickins unsigned int i = 0; 10721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int retval = 0; 10731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 10751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * When searching mms for an entry, a good strategy is to 10761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * start at the first mm we freed the previous entry from 10771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * (though actually we don't notice whether we or coincidence 10781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * freed the entry). Initialize this start_mm with a hold. 10791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 10801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * A simpler strategy would be to start at the last mm we 10811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * freed the previous entry from; but that would take less 10821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * advantage of mmlist ordering, which clusters forked mms 10831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * together, child after parent. If we race with dup_mmap(), we 10841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * prefer to resolve parent before child, lest we miss entries 10851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * duplicated after we scanned child: using last mm would invert 1086570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * that. 10871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds start_mm = &init_mm; 10891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds atomic_inc(&init_mm.mm_users); 10901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 10911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 10921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Keep on scanning until all entries have gone. Usually, 10931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * one pass through swap_map is enough, but not necessarily: 10941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * there are races when an instance of an entry might be missed. 10951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 10961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds while ((i = find_next_to_unuse(si, i)) != 0) { 10971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (signal_pending(current)) { 10981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds retval = -EINTR; 10991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 11001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 11011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1102886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins /* 11031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Get a page for the entry, using the existing swap 11041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * cache page if there is one. Otherwise, get a clean 1105886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins * page and read the swap into it. 11061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 11071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_map = &si->swap_map[i]; 11081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds entry = swp_entry(type, i); 110902098feaa42b2e0087fbbe6c6ab9a23e4653b16aHugh Dickins page = read_swap_cache_async(entry, 111002098feaa42b2e0087fbbe6c6ab9a23e4653b16aHugh Dickins GFP_HIGHUSER_MOVABLE, NULL, 0); 11111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!page) { 11121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 11131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Either swap_duplicate() failed because entry 11141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * has been freed independently, and will not be 11151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * reused since sys_swapoff() already disabled 11161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * allocation from here, or alloc_page() failed. 11171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 11181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!*swap_map) 11191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 11201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds retval = -ENOMEM; 11211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 11221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 11231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 11251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Don't hold on to start_mm if it looks like exiting. 11261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 11271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (atomic_read(&start_mm->mm_users) == 1) { 11281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(start_mm); 11291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds start_mm = &init_mm; 11301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds atomic_inc(&init_mm.mm_users); 11311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 11321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 11341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Wait for and lock page. When do_swap_page races with 11351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * try_to_unuse, do_swap_page can handle the fault much 11361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * faster than try_to_unuse can locate the entry. This 11371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * apparently redundant "wait_on_page_locked" lets try_to_unuse 11381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * defer to do_swap_page in such a case - in some tests, 11391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * do_swap_page and try_to_unuse repeatedly compete. 11401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 11411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_on_page_locked(page); 11421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_on_page_writeback(page); 11431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds lock_page(page); 11441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_on_page_writeback(page); 11451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 11471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Remove all references to entry. 11481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 11491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swcount = *swap_map; 1150aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins if (swap_count(swcount) == SWAP_MAP_SHMEM) { 1151aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins retval = shmem_unuse(entry, page); 1152aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins /* page has already been unlocked and released */ 1153aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins if (retval < 0) 1154aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins break; 1155aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins continue; 11561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1157aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins if (swap_count(swcount) && start_mm != &init_mm) 1158aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins retval = unuse_mm(start_mm, entry, page); 1159aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins 1160355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (swap_count(*swap_map)) { 11611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int set_start_mm = (*swap_map >= swcount); 11621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct list_head *p = &start_mm->mmlist; 11631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mm_struct *new_start_mm = start_mm; 11641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mm_struct *prev_mm = start_mm; 11651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mm_struct *mm; 11661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds atomic_inc(&new_start_mm->mm_users); 11681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds atomic_inc(&prev_mm->mm_users); 11691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_lock(&mmlist_lock); 1170aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins while (swap_count(*swap_map) && !retval && 11711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds (p = p->next) != &start_mm->mmlist) { 11721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mm = list_entry(p, struct mm_struct, mmlist); 117370af7c5c6492ef6ad137dbff6c4568c73edbcaf0Hugh Dickins if (!atomic_inc_not_zero(&mm->mm_users)) 11741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 11751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_unlock(&mmlist_lock); 11761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(prev_mm); 11771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds prev_mm = mm; 11781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds cond_resched(); 11801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 11811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swcount = *swap_map; 1182355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (!swap_count(swcount)) /* any usage ? */ 11831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ; 1184aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins else if (mm == &init_mm) 11851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_start_mm = 1; 1186aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins else 11871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds retval = unuse_mm(mm, entry, page); 1188355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 118932c5fc10e79a7053ac5728b01a0bff55cbcb9d49Bo Liu if (set_start_mm && *swap_map < swcount) { 11901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(new_start_mm); 11911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds atomic_inc(&mm->mm_users); 11921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds new_start_mm = mm; 11931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_start_mm = 0; 11941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 11951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_lock(&mmlist_lock); 11961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 11971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_unlock(&mmlist_lock); 11981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(prev_mm); 11991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(start_mm); 12001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds start_mm = new_start_mm; 12011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 12021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (retval) { 12031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unlock_page(page); 12041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_cache_release(page); 12051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 12061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 12071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 12091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * If a reference remains (rare), we would like to leave 12101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * the page in the swap cache; but try_to_unmap could 12111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * then re-duplicate the entry once we drop page lock, 12121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * so we might loop indefinitely; also, that page could 12131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * not be swapped out to other storage meanwhile. So: 12141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * delete from cache even if there's another reference, 12151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * after ensuring that the data has been saved to disk - 12161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * since if the reference remains (rarer), it will be 12171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * read from disk into another page. Splitting into two 12181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * pages would be incorrect if swap supported "shared 12191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * private" pages, but they are handled by tmpfs files. 12205ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * 12215ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * Given how unuse_vma() targets one particular offset 12225ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * in an anon_vma, once the anon_vma has been determined, 12235ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * this splitting happens to be just what is needed to 12245ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * handle where KSM pages have been swapped out: re-reading 12255ad6468801d28c4d4ac9f48ec19297817c915f6aHugh Dickins * is unnecessarily slow, but we can fix that later on. 12261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 1227355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (swap_count(*swap_map) && 1228355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki PageDirty(page) && PageSwapCache(page)) { 12291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct writeback_control wbc = { 12301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .sync_mode = WB_SYNC_NONE, 12311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds }; 12321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_writepage(page, &wbc); 12341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds lock_page(page); 12351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_on_page_writeback(page); 12361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 123768bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins 123868bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins /* 123968bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins * It is conceivable that a racing task removed this page from 124068bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins * swap cache just before we acquired the page lock at the top, 124168bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins * or while we dropped it in unuse_mm(). The page might even 124268bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins * be back in swap cache on another swap area: that we must not 124368bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins * delete, since it may not have been written out to swap yet. 124468bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins */ 124568bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins if (PageSwapCache(page) && 124668bdc8d64742ccc5e340c5d122ebbab3f0cf2a74Hugh Dickins likely(page_private(page) == entry.val)) 12472e0e26c76a35de8f8bec6b2b917518cfeb52888aHugh Dickins delete_from_swap_cache(page); 12481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 12501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * So we could skip searching mms once swap count went 12511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * to 1, we did not mark any present ptes as dirty: must 12522706a1b89b1a3e7434a668d4a9d15f616da96685Anderson Briglia * mark page dirty so shrink_page_list will preserve it. 12531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 12541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds SetPageDirty(page); 12551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unlock_page(page); 12561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_cache_release(page); 12571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 12591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Make sure that we aren't completely killing 12601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * interactive performance. 12611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 12621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds cond_resched(); 12631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 12641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mmput(start_mm); 12661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return retval; 12671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 12681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 12705d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * After a successful try_to_unuse, if no swap is now in use, we know 12715d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * we can empty the mmlist. swap_lock must be held on entry and exit. 12725d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * Note that mmlist_lock nests inside swap_lock, and an mm must be 12731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * added to the mmlist just after page_duplicate - before would be racy. 12741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 12751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void drain_mmlist(void) 12761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 12771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct list_head *p, *next; 1278efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins unsigned int type; 12791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1280efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = 0; type < nr_swapfiles; type++) 1281efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (swap_info[type]->inuse_pages) 12821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return; 12831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_lock(&mmlist_lock); 12841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds list_for_each_safe(p, next, &init_mm.mmlist) 12851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds list_del_init(p); 12861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds spin_unlock(&mmlist_lock); 12871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 12881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 12901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Use this swapdev's extent info to locate the (PAGE_SIZE) block which 1291d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn * corresponds to page offset for the specified swap entry. 1292d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn * Note that the type of this function is sector_t, but it returns page offset 1293d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn * into the bdev, not sector offset. 12941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 1295d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhornstatic sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) 12961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1297f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins struct swap_info_struct *sis; 1298f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins struct swap_extent *start_se; 1299f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins struct swap_extent *se; 1300f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins pgoff_t offset; 1301f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins 1302efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins sis = swap_info[swp_type(entry)]; 1303f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins *bdev = sis->bdev; 1304f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins 1305f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins offset = swp_offset(entry); 1306f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins start_se = sis->curr_swap_extent; 1307f29ad6a99b596b8169744d107bf088e8be9e8d0dHugh Dickins se = start_se; 13081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds for ( ; ; ) { 13101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct list_head *lh; 13111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (se->start_page <= offset && 13131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds offset < (se->start_page + se->nr_pages)) { 13141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return se->start_block + (offset - se->start_page); 13151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 131611d31886dbcb61039ed3789e583d21c6e70960fdHugh Dickins lh = se->list.next; 13171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds se = list_entry(lh, struct swap_extent, list); 13181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sis->curr_swap_extent = se; 13191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds BUG_ON(se == start_se); /* It *must* be present */ 13201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 13211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 13221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 1324d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn * Returns the page offset into bdev for the specified page's swap entry. 1325d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn */ 1326d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhornsector_t map_swap_page(struct page *page, struct block_device **bdev) 1327d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn{ 1328d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn swp_entry_t entry; 1329d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn entry.val = page_private(page); 1330d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn return map_swap_entry(entry, bdev); 1331d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn} 1332d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn 1333d4906e1aa516cc965292b43b5a26122dd4344e7eLee Schermerhorn/* 13341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Free all of a swapdev's extent information 13351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 13361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void destroy_swap_extents(struct swap_info_struct *sis) 13371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 13389625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins while (!list_empty(&sis->first_swap_extent.list)) { 13391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct swap_extent *se; 13401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13419625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se = list_entry(sis->first_swap_extent.list.next, 13421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct swap_extent, list); 13431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds list_del(&se->list); 13441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds kfree(se); 13451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 13461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 13471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 13491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Add a block range (and the corresponding page range) into this swapdev's 135011d31886dbcb61039ed3789e583d21c6e70960fdHugh Dickins * extent list. The extent list is kept sorted in page order. 13511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 135211d31886dbcb61039ed3789e583d21c6e70960fdHugh Dickins * This function rather assumes that it is called in ascending page order. 13531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 13541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int 13551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsadd_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 13561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long nr_pages, sector_t start_block) 13571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 13581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct swap_extent *se; 13591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct swap_extent *new_se; 13601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct list_head *lh; 13611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13629625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins if (start_page == 0) { 13639625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se = &sis->first_swap_extent; 13649625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins sis->curr_swap_extent = se; 13659625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se->start_page = 0; 13669625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se->nr_pages = nr_pages; 13679625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins se->start_block = start_block; 13689625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins return 1; 13699625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins } else { 13709625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins lh = sis->first_swap_extent.list.prev; /* Highest extent */ 13711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds se = list_entry(lh, struct swap_extent, list); 137211d31886dbcb61039ed3789e583d21c6e70960fdHugh Dickins BUG_ON(se->start_page + se->nr_pages != start_page); 137311d31886dbcb61039ed3789e583d21c6e70960fdHugh Dickins if (se->start_block + se->nr_pages == start_block) { 13741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* Merge it */ 13751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds se->nr_pages += nr_pages; 13761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 13771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 13781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 13791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 13811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * No merge. Insert a new extent, preserving ordering. 13821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 13831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds new_se = kmalloc(sizeof(*se), GFP_KERNEL); 13841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (new_se == NULL) 13851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -ENOMEM; 13861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds new_se->start_page = start_page; 13871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds new_se->nr_pages = nr_pages; 13881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds new_se->start_block = start_block; 13891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13909625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins list_add_tail(&new_se->list, &sis->first_swap_extent.list); 139153092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins return 1; 13921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 13931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 13941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 13951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * A `swap extent' is a simple thing which maps a contiguous range of pages 13961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * onto a contiguous range of disk blocks. An ordered list of swap extents 13971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * is built at swapon time and is then used at swap_writepage/swap_readpage 13981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * time for locating where on disk a page belongs. 13991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 14001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * If the swapfile is an S_ISBLK block device, a single extent is installed. 14011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * This is done so that the main operating code can treat S_ISBLK and S_ISREG 14021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * swap files identically. 14031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 14041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap 14051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK 14061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * swapfiles are handled *identically* after swapon time. 14071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 14081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks 14091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If 14101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * some stray blocks are found which do not fall within the PAGE_SIZE alignment 14111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * requirements, they are simply tossed out - we will never use those blocks 14121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * for swapping. 14131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 1414b0d9bcd4bb79a7834f8492f2ae5c2655a551f23dHugh Dickins * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This 14151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * prevents root from shooting her foot off by ftruncating an in-use swapfile, 14161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * which will scribble on the fs. 14171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 14181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * The amount of disk space which a single swap extent represents varies. 14191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Typically it is in the 1-4 megabyte range. So we can have hundreds of 14201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * extents in the list. To avoid much list walking, we cache the previous 14211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * search location in `curr_swap_extent', and start new searches from there. 14221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * This is extremely effective. The average number of iterations in 14231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * map_swap_page() has been measured at about 0.3 per page. - akpm. 14241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 142553092a7402f227151a681b0c92ec8598c5618b1aHugh Dickinsstatic int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) 14261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 14271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct inode *inode; 14281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned blocks_per_page; 14291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long page_no; 14301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned blkbits; 14311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sector_t probe_block; 14321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sector_t last_block; 143353092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins sector_t lowest_block = -1; 143453092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins sector_t highest_block = 0; 143553092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins int nr_extents = 0; 14361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int ret; 14371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds inode = sis->swap_file->f_mapping->host; 14391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (S_ISBLK(inode->i_mode)) { 14401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ret = add_swap_extent(sis, 0, sis->max, 0); 144153092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins *span = sis->pages; 14429625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins goto out; 14431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 14441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds blkbits = inode->i_blkbits; 14461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds blocks_per_page = PAGE_SIZE >> blkbits; 14471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 14491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Map all the blocks into the extent list. This code doesn't try 14501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * to be very smart. 14511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 14521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds probe_block = 0; 14531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_no = 0; 14541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds last_block = i_size_read(inode) >> blkbits; 14551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds while ((probe_block + blocks_per_page) <= last_block && 14561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_no < sis->max) { 14571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned block_in_page; 14581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sector_t first_block; 14591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds first_block = bmap(inode, probe_block); 14611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (first_block == 0) 14621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_bmap; 14631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 14651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * It must be PAGE_SIZE aligned on-disk 14661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 14671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (first_block & (blocks_per_page - 1)) { 14681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds probe_block++; 14691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto reprobe; 14701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 14711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds for (block_in_page = 1; block_in_page < blocks_per_page; 14731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds block_in_page++) { 14741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sector_t block; 14751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 14761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds block = bmap(inode, probe_block + block_in_page); 14771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (block == 0) 14781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_bmap; 14791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (block != first_block + block_in_page) { 14801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* Discontiguity */ 14811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds probe_block++; 14821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto reprobe; 14831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 14841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 14851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 148653092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins first_block >>= (PAGE_SHIFT - blkbits); 148753092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins if (page_no) { /* exclude the header page */ 148853092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins if (first_block < lowest_block) 148953092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins lowest_block = first_block; 149053092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins if (first_block > highest_block) 149153092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins highest_block = first_block; 149253092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins } 149353092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins 14941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 14951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks 14961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 149753092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins ret = add_swap_extent(sis, page_no, 1, first_block); 149853092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins if (ret < 0) 14991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 150053092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins nr_extents += ret; 15011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_no++; 15021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds probe_block += blocks_per_page; 15031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsreprobe: 15041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 15051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 150653092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins ret = nr_extents; 150753092a7402f227151a681b0c92ec8598c5618b1aHugh Dickins *span = 1 + highest_block - lowest_block; 15081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (page_no == 0) 1509e2244ec2efa4ee1edf391d0001d314933e2b2974Hugh Dickins page_no = 1; /* force Empty message */ 15101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sis->max = page_no; 1511e2244ec2efa4ee1edf391d0001d314933e2b2974Hugh Dickins sis->pages = page_no - 1; 15121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sis->highest_bit = page_no - 1; 15139625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickinsout: 15149625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins return ret; 15151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_bmap: 15161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swapon: swapfile has holes\n"); 15171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ret = -EINVAL; 15189625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins goto out; 15191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 15201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 152140531542e2832419566c997af0808513f6f2815dCesar Eduardo Barrosstatic void enable_swap_info(struct swap_info_struct *p, int prio, 152240531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros unsigned char *swap_map) 152340531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros{ 152440531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros int i, prev; 152540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros 152640531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros spin_lock(&swap_lock); 152740531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros if (prio >= 0) 152840531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros p->prio = prio; 152940531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros else 153040531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros p->prio = --least_priority; 153140531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros p->swap_map = swap_map; 153240531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros p->flags |= SWP_WRITEOK; 153340531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros nr_swap_pages += p->pages; 153440531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros total_swap_pages += p->pages; 153540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros 153640531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros /* insert swap space into swap_list: */ 153740531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros prev = -1; 153840531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { 153940531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros if (p->prio >= swap_info[i]->prio) 154040531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros break; 154140531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros prev = i; 154240531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros } 154340531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros p->next = i; 154440531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros if (prev < 0) 154540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros swap_list.head = swap_list.next = p->type; 154640531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros else 154740531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros swap_info[prev]->next = p->type; 154840531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros spin_unlock(&swap_lock); 154940531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros} 155040531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros 1551c4ea37c26a691ad0b7e86aa5884aab27830e95c9Heiko CarstensSYSCALL_DEFINE1(swapoff, const char __user *, specialfile) 15521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 155373c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct swap_info_struct *p = NULL; 15548d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char *swap_map; 15551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct file *swap_file, *victim; 15561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct address_space *mapping; 15571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct inode *inode; 155873c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins char *pathname; 155972788c385604523422592249c19cba0187021e9bDavid Rientjes int oom_score_adj; 15601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int i, type, prev; 15611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int err; 1562886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins 15631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!capable(CAP_SYS_ADMIN)) 15641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -EPERM; 15651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 15661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pathname = getname(specialfile); 15671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = PTR_ERR(pathname); 15681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (IS_ERR(pathname)) 15691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 15701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 15711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); 15721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds putname(pathname); 15731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = PTR_ERR(victim); 15741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (IS_ERR(victim)) 15751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 15761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 15771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mapping = victim->f_mapping; 15781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds prev = -1; 15795d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 1580efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = swap_list.head; type >= 0; type = swap_info[type]->next) { 1581efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p = swap_info[type]; 158222c6f8fdb31993cf49bdd4a47b64a7002391e1c7Hugh Dickins if (p->flags & SWP_WRITEOK) { 15831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (p->swap_file->f_mapping == mapping) 15841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 15851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 15861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds prev = type; 15871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 15881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (type < 0) { 15891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = -EINVAL; 15905d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 15911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out_dput; 15921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 15931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!security_vm_enough_memory(p->pages)) 15941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds vm_unacct_memory(p->pages); 15951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds else { 15961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = -ENOMEM; 15975d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 15981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out_dput; 15991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1600efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (prev < 0) 16011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_list.head = p->next; 1602efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins else 1603efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins swap_info[prev]->next = p->next; 16041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (type == swap_list.next) { 16051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* just pick something that's safe... */ 16061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_list.next = swap_list.head; 16071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 160878ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickins if (p->prio < 0) { 1609efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (i = p->next; i >= 0; i = swap_info[i]->next) 1610efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins swap_info[i]->prio = p->prio--; 161178ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickins least_priority++; 161278ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickins } 16131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds nr_swap_pages -= p->pages; 16141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds total_swap_pages -= p->pages; 16151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->flags &= ~SWP_WRITEOK; 16165d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 1617fb4f88dcabdc716c7c350e09cf4a38a419b007e1Hugh Dickins 161872788c385604523422592249c19cba0187021e9bDavid Rientjes oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX); 16191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = try_to_unuse(type); 162043362a4977e37db46f86f7e6ab935f0006956632David Rientjes compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX, oom_score_adj); 16211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 16221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (err) { 162340531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros /* 162440531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros * reading p->prio and p->swap_map outside the lock is 162540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros * safe here because only sys_swapon and sys_swapoff 162640531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros * change them, and there can be no other sys_swapon or 162740531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros * sys_swapoff for this swap_info_struct at this point. 162840531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros */ 16291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* re-insert swap space back into swap_list */ 163040531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros enable_swap_info(p, p->prio, p->swap_map); 16311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out_dput; 16321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 163352b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins 16345d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins destroy_swap_extents(p); 1635570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (p->flags & SWP_CONTINUED) 1636570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins free_swap_count_continuations(p); 1637570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 1638fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_lock(&swapon_mutex); 16395d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 16405d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins drain_mmlist(); 16415d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins 164252b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins /* wait for anyone still in scan_swap_map */ 164352b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins p->highest_bit = 0; /* cuts scans short */ 164452b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins while (p->flags >= SWP_SCANNING) { 16455d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 164613e4b57f6a4e23ceb99794a650d777e74831f4a6Nishanth Aravamudan schedule_timeout_uninterruptible(1); 16475d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 164852b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins } 164952b7efdbe5f5696fc80338560a3fc51e0b0a993cHugh Dickins 16501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_file = p->swap_file; 16511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->swap_file = NULL; 16521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->max = 0; 16531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_map = p->swap_map; 16541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->swap_map = NULL; 16551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->flags = 0; 16565d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 1657fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_unlock(&swapon_mutex); 16581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds vfree(swap_map); 165927a7faa0779dd13729196c1a818c294f44bbd1eeKAMEZAWA Hiroyuki /* Destroy swap account informatin */ 166027a7faa0779dd13729196c1a818c294f44bbd1eeKAMEZAWA Hiroyuki swap_cgroup_swapoff(type); 166127a7faa0779dd13729196c1a818c294f44bbd1eeKAMEZAWA Hiroyuki 16621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds inode = mapping->host; 16631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (S_ISBLK(inode->i_mode)) { 16641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct block_device *bdev = I_BDEV(inode); 16651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_blocksize(bdev, p->old_block_size); 1666e525fd89d380c4a94c0d63913a1dd1a593ed25e7Tejun Heo blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); 16671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } else { 16681b1dcc1b57a49136f118a0f16367256ff9994a69Jes Sorensen mutex_lock(&inode->i_mutex); 16691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds inode->i_flags &= ~S_SWAPFILE; 16701b1dcc1b57a49136f118a0f16367256ff9994a69Jes Sorensen mutex_unlock(&inode->i_mutex); 16711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 16721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds filp_close(swap_file, NULL); 16731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds err = 0; 167466d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers atomic_inc(&proc_poll_event); 167566d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers wake_up_interruptible(&proc_poll_wait); 16761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 16771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout_dput: 16781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds filp_close(victim, NULL); 16791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout: 16801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return err; 16811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 16821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 16831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#ifdef CONFIG_PROC_FS 168466d7dd518ae413a383ab2c6c263cc30617329842Kay Sieversstatic unsigned swaps_poll(struct file *file, poll_table *wait) 168566d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers{ 1686f15146380d28b746df3c8b81b392812eb982382aKay Sievers struct seq_file *seq = file->private_data; 168766d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 168866d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers poll_wait(file, &proc_poll_wait, wait); 168966d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 1690f15146380d28b746df3c8b81b392812eb982382aKay Sievers if (seq->poll_event != atomic_read(&proc_poll_event)) { 1691f15146380d28b746df3c8b81b392812eb982382aKay Sievers seq->poll_event = atomic_read(&proc_poll_event); 169266d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers return POLLIN | POLLRDNORM | POLLERR | POLLPRI; 169366d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers } 169466d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 169566d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers return POLLIN | POLLRDNORM; 169666d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers} 169766d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 16981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* iterator */ 16991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void *swap_start(struct seq_file *swap, loff_t *pos) 17001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1701efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *si; 1702efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins int type; 17031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds loff_t l = *pos; 17041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1705fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_lock(&swapon_mutex); 17061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1707881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal if (!l) 1708881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal return SEQ_START_TOKEN; 1709881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal 1710efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = 0; type < nr_swapfiles; type++) { 1711efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins smp_rmb(); /* read nr_swapfiles before swap_info[type] */ 1712efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si = swap_info[type]; 1713efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (!(si->flags & SWP_USED) || !si->swap_map) 17141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 1715881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal if (!--l) 1716efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins return si; 17171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 17181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return NULL; 17201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 17211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void *swap_next(struct seq_file *swap, void *v, loff_t *pos) 17231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1724efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *si = v; 1725efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins int type; 17261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1727881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal if (v == SEQ_START_TOKEN) 1728efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins type = 0; 1729efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins else 1730efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins type = si->type + 1; 1731881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal 1732efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (; type < nr_swapfiles; type++) { 1733efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins smp_rmb(); /* read nr_swapfiles before swap_info[type] */ 1734efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si = swap_info[type]; 1735efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (!(si->flags & SWP_USED) || !si->swap_map) 17361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 17371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ++*pos; 1738efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins return si; 17391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 17401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return NULL; 17421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 17431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void swap_stop(struct seq_file *swap, void *v) 17451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1746fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_unlock(&swapon_mutex); 17471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 17481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int swap_show(struct seq_file *swap, void *v) 17501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1751efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *si = v; 17521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct file *file; 17531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int len; 17541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1755efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (si == SEQ_START_TOKEN) { 1756881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); 1757881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal return 0; 1758881e4aabe4c6b3fce93674b67c6adc646fe2683bSuleiman Souhlal } 17591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1760efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins file = si->swap_file; 1761c32c2f63a9d6c953aaf168c0b2551da9734f76d2Jan Blunck len = seq_path(swap, &file->f_path, " \t\n\\"); 17626eb396dc4a9781c5e7951143ab56ce5710687ab3Hugh Dickins seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", 1763886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins len < 40 ? 40 - len : 1, " ", 1764886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins S_ISBLK(file->f_path.dentry->d_inode->i_mode) ? 17651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds "partition" : "file\t", 1766efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si->pages << (PAGE_SHIFT - 10), 1767efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si->inuse_pages << (PAGE_SHIFT - 10), 1768efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si->prio); 17691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 17701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 17711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 177215ad7cdcfd76450d4beebc789ec646664238184dHelge Dellerstatic const struct seq_operations swaps_op = { 17731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .start = swap_start, 17741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .next = swap_next, 17751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .stop = swap_stop, 17761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .show = swap_show 17771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}; 17781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 17791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int swaps_open(struct inode *inode, struct file *file) 17801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1781f15146380d28b746df3c8b81b392812eb982382aKay Sievers struct seq_file *seq; 178266d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers int ret; 178366d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 178466d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers ret = seq_open(file, &swaps_op); 1785f15146380d28b746df3c8b81b392812eb982382aKay Sievers if (ret) 178666d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers return ret; 178766d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 1788f15146380d28b746df3c8b81b392812eb982382aKay Sievers seq = file->private_data; 1789f15146380d28b746df3c8b81b392812eb982382aKay Sievers seq->poll_event = atomic_read(&proc_poll_event); 1790f15146380d28b746df3c8b81b392812eb982382aKay Sievers return 0; 17911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 17921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 179315ad7cdcfd76450d4beebc789ec646664238184dHelge Dellerstatic const struct file_operations proc_swaps_operations = { 17941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .open = swaps_open, 17951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .read = seq_read, 17961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .llseek = seq_lseek, 17971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .release = seq_release, 179866d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers .poll = swaps_poll, 17991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}; 18001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 18011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int __init procswaps_init(void) 18021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 18033d71f86f4dfccd749e4421f10301f3f3b31da88aDenis V. Lunev proc_create("swaps", 0, NULL, &proc_swaps_operations); 18041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 18051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 18061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds__initcall(procswaps_init); 18071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#endif /* CONFIG_PROC_FS */ 18081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 18091796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich#ifdef MAX_SWAPFILES_CHECK 18101796316a8b028a148be48ba5d4e7be493a39d173Jan Beulichstatic int __init max_swapfiles_check(void) 18111796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich{ 18121796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich MAX_SWAPFILES_CHECK(); 18131796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich return 0; 18141796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich} 18151796316a8b028a148be48ba5d4e7be493a39d173Jan Beulichlate_initcall(max_swapfiles_check); 18161796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich#endif 18171796316a8b028a148be48ba5d4e7be493a39d173Jan Beulich 181853cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barrosstatic struct swap_info_struct *alloc_swap_info(void) 18191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 182073c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct swap_info_struct *p; 18211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int type; 1822efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins 1823efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p = kzalloc(sizeof(*p), GFP_KERNEL); 1824efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (!p) 182553cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros return ERR_PTR(-ENOMEM); 1826efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins 18275d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 1828efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = 0; type < nr_swapfiles; type++) { 1829efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (!(swap_info[type]->flags & SWP_USED)) 18301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 1831efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins } 18320697212a411c1dae03c27845f2de2f3adb32c331Christoph Lameter if (type >= MAX_SWAPFILES) { 18335d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 1834efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins kfree(p); 1835730c0581c82dbc5be2f41a2d85bde6bad11bc8a4Cesar Eduardo Barros return ERR_PTR(-EPERM); 18361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1837efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if (type >= nr_swapfiles) { 1838efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p->type = type; 1839efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins swap_info[type] = p; 1840efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins /* 1841efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins * Write swap_info[type] before nr_swapfiles, in case a 1842efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins * racing procfs swap_start() or swap_next() is reading them. 1843efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins * (We never shrink nr_swapfiles, we never free this entry.) 1844efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins */ 1845efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins smp_wmb(); 1846efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins nr_swapfiles++; 1847efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins } else { 1848efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins kfree(p); 1849efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p = swap_info[type]; 1850efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins /* 1851efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins * Do not memset this entry: a racing procfs swap_next() 1852efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins * would be relying on p->type to remain valid. 1853efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins */ 1854efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins } 18559625a5f289f7c3c100b59c317e2bcc3c7e2e51fbHugh Dickins INIT_LIST_HEAD(&p->first_swap_extent.list); 18561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->flags = SWP_USED; 18571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->next = -1; 18585d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 1859efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins 186053cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros return p; 186153cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros} 186253cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros 18634d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barrosstatic int claim_swapfile(struct swap_info_struct *p, struct inode *inode) 18644d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros{ 18654d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros int error; 18664d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros 18674d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros if (S_ISBLK(inode->i_mode)) { 18684d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros p->bdev = bdgrab(I_BDEV(inode)); 18694d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros error = blkdev_get(p->bdev, 18704d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros FMODE_READ | FMODE_WRITE | FMODE_EXCL, 18714d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros sys_swapon); 18724d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros if (error < 0) { 18734d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros p->bdev = NULL; 187487ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros return -EINVAL; 18754d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros } 18764d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros p->old_block_size = block_size(p->bdev); 18774d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros error = set_blocksize(p->bdev, PAGE_SIZE); 18784d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros if (error < 0) 187987ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros return error; 18804d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros p->flags |= SWP_BLKDEV; 18814d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros } else if (S_ISREG(inode->i_mode)) { 18824d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros p->bdev = inode->i_sb->s_bdev; 18834d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros mutex_lock(&inode->i_mutex); 188487ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros if (IS_SWAPFILE(inode)) 188587ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros return -EBUSY; 188687ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros } else 188787ade72a799a9a895b4a60918c32b43d3dfc3324Cesar Eduardo Barros return -EINVAL; 18884d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros 18894d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros return 0; 18904d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros} 18914d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros 1892ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barrosstatic unsigned long read_swap_header(struct swap_info_struct *p, 1893ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros union swap_header *swap_header, 1894ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros struct inode *inode) 1895ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros{ 1896ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros int i; 1897ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros unsigned long maxpages; 1898ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros unsigned long swapfilepages; 1899ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1900ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) { 1901ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros printk(KERN_ERR "Unable to find swap-space signature\n"); 190238719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1903ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros } 1904ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1905ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros /* swap partition endianess hack... */ 1906ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (swab32(swap_header->info.version) == 1) { 1907ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swab32s(&swap_header->info.version); 1908ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swab32s(&swap_header->info.last_page); 1909ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swab32s(&swap_header->info.nr_badpages); 1910ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros for (i = 0; i < swap_header->info.nr_badpages; i++) 1911ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swab32s(&swap_header->info.badpages[i]); 1912ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros } 1913ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros /* Check the swap header's sub-version */ 1914ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (swap_header->info.version != 1) { 1915ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros printk(KERN_WARNING 1916ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros "Unable to handle swap header version %d\n", 1917ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swap_header->info.version); 191838719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1919ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros } 1920ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1921ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros p->lowest_bit = 1; 1922ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros p->cluster_next = 1; 1923ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros p->cluster_nr = 0; 1924ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1925ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros /* 1926ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros * Find out how many pages are allowed for a single swap 1927a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * device. There are three limiting factors: 1) the number 1928a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * of bits for the swap offset in the swp_entry_t type, and 1929a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * 2) the number of bits in the swap pte as defined by the 1930a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * the different architectures, and 3) the number of free bits 1931a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * in an exceptional radix_tree entry. In order to find the 1932a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * largest possible bit mask, a swap entry with swap type 0 1933ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros * and swap offset ~0UL is created, encoded to a swap pte, 1934a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * decoded to a swp_entry_t again, and finally the swap 1935ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros * offset is extracted. This will mask all the bits from 1936ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros * the initial ~0UL mask that can't be encoded in either 1937ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros * the swp_entry_t or the architecture definition of a 1938a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins * swap pte. Then the same is done for a radix_tree entry. 1939ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros */ 1940ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros maxpages = swp_offset(pte_to_swp_entry( 1941a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins swp_entry_to_pte(swp_entry(0, ~0UL)))); 1942a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins maxpages = swp_offset(radix_to_swp_entry( 1943a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins swp_to_radix_entry(swp_entry(0, maxpages)))) + 1; 1944a2c16d6cb0e478812829ca84aeabd02e36af35ebHugh Dickins 1945ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (maxpages > swap_header->info.last_page) { 1946ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros maxpages = swap_header->info.last_page + 1; 1947ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros /* p->max is an unsigned int: don't overflow it */ 1948ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if ((unsigned int)maxpages == 0) 1949ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros maxpages = UINT_MAX; 1950ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros } 1951ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros p->highest_bit = maxpages - 1; 1952ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1953ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (!maxpages) 195438719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1955ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros swapfilepages = i_size_read(inode) >> PAGE_SHIFT; 1956ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (swapfilepages && maxpages > swapfilepages) { 1957ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros printk(KERN_WARNING 1958ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros "Swap area shorter than signature indicates\n"); 195938719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1960ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros } 1961ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) 196238719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1963ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) 196438719025384cf7121331bd6d41c062d3c5f7bb91Cesar Eduardo Barros return 0; 1965ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1966ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros return maxpages; 1967ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros} 1968ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros 1969915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barrosstatic int setup_swap_map_and_extents(struct swap_info_struct *p, 1970915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros union swap_header *swap_header, 1971915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros unsigned char *swap_map, 1972915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros unsigned long maxpages, 1973915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros sector_t *span) 1974915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros{ 1975915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros int i; 1976915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros unsigned int nr_good_pages; 1977915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros int nr_extents; 1978915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros 1979915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros nr_good_pages = maxpages - 1; /* omit header page */ 1980915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros 1981915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros for (i = 0; i < swap_header->info.nr_badpages; i++) { 1982915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros unsigned int page_nr = swap_header->info.badpages[i]; 1983bdb8e3f68320f897de3f3a4c363fe2802037f21dCesar Eduardo Barros if (page_nr == 0 || page_nr > swap_header->info.last_page) 1984bdb8e3f68320f897de3f3a4c363fe2802037f21dCesar Eduardo Barros return -EINVAL; 1985915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros if (page_nr < maxpages) { 1986915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros swap_map[page_nr] = SWAP_MAP_BAD; 1987915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros nr_good_pages--; 1988915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros } 1989915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros } 1990915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros 1991915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros if (nr_good_pages) { 1992915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros swap_map[0] = SWAP_MAP_BAD; 1993915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros p->max = maxpages; 1994915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros p->pages = nr_good_pages; 1995915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros nr_extents = setup_swap_extents(p, span); 1996bdb8e3f68320f897de3f3a4c363fe2802037f21dCesar Eduardo Barros if (nr_extents < 0) 1997bdb8e3f68320f897de3f3a4c363fe2802037f21dCesar Eduardo Barros return nr_extents; 1998915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros nr_good_pages = p->pages; 1999915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros } 2000915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros if (!nr_good_pages) { 2001915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros printk(KERN_WARNING "Empty swap-file\n"); 2002bdb8e3f68320f897de3f3a4c363fe2802037f21dCesar Eduardo Barros return -EINVAL; 2003915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros } 2004915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros 2005915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros return nr_extents; 2006915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros} 2007915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros 200853cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo BarrosSYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) 200953cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros{ 201053cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros struct swap_info_struct *p; 201128b36bd741bd44db30e12b1048a659aa346e9b76Cesar Eduardo Barros char *name; 201253cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros struct file *swap_file = NULL; 201353cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros struct address_space *mapping; 201440531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros int i; 201540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros int prio; 201653cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros int error; 201753cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros union swap_header *swap_header; 2018915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros int nr_extents; 201953cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros sector_t span; 202053cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros unsigned long maxpages; 202153cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros unsigned char *swap_map = NULL; 202253cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros struct page *page = NULL; 202353cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros struct inode *inode = NULL; 202453cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros 202553cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros if (!capable(CAP_SYS_ADMIN)) 202653cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros return -EPERM; 202753cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros 202853cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros p = alloc_swap_info(); 20292542e5134d2c19a9e6a4e641ef78cac6bccebd9bCesar Eduardo Barros if (IS_ERR(p)) 20302542e5134d2c19a9e6a4e641ef78cac6bccebd9bCesar Eduardo Barros return PTR_ERR(p); 203153cbb2435f161f2a8b36af8f6d2c46dc59d0d757Cesar Eduardo Barros 20321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds name = getname(specialfile); 20331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (IS_ERR(name)) { 20347de7fb6b3422e6d1dac00666a992834085e745dcCesar Eduardo Barros error = PTR_ERR(name); 20351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds name = NULL; 2036bd69010b042a60ca41a890df1b10019e94746c2fCesar Eduardo Barros goto bad_swap; 20371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 20381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); 20391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (IS_ERR(swap_file)) { 20407de7fb6b3422e6d1dac00666a992834085e745dcCesar Eduardo Barros error = PTR_ERR(swap_file); 20411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds swap_file = NULL; 2042bd69010b042a60ca41a890df1b10019e94746c2fCesar Eduardo Barros goto bad_swap; 20431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 20441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->swap_file = swap_file; 20461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mapping = swap_file->f_mapping; 20471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds for (i = 0; i < nr_swapfiles; i++) { 2049efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *q = swap_info[i]; 20501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2051e8e6c2ec403ecfaa226857d8204344c98fe12b7bCesar Eduardo Barros if (q == p || !q->swap_file) 20521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds continue; 20537de7fb6b3422e6d1dac00666a992834085e745dcCesar Eduardo Barros if (mapping == q->swap_file->f_mapping) { 20547de7fb6b3422e6d1dac00666a992834085e745dcCesar Eduardo Barros error = -EBUSY; 20551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 20567de7fb6b3422e6d1dac00666a992834085e745dcCesar Eduardo Barros } 20571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 20581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20592130781e2aaab66e5a9f2fdc8af35da0153f405cCesar Eduardo Barros inode = mapping->host; 20602130781e2aaab66e5a9f2fdc8af35da0153f405cCesar Eduardo Barros /* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */ 20614d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros error = claim_swapfile(p, inode); 20624d0e1e10752ca487d83d1ab2a1d4ae6d664e1cc0Cesar Eduardo Barros if (unlikely(error)) 20631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 20641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 20661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Read the swap header. 20671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 20681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!mapping->a_ops->readpage) { 20691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds error = -EINVAL; 20701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 20711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2072090d2b185d8680fc26a2eaf4245d4171dcf4baf1Pekka Enberg page = read_mapping_page(mapping, 0, swap_file); 20731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (IS_ERR(page)) { 20741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds error = PTR_ERR(page); 20751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 20761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 207781e33971271ec8603fe696731ff9967afb99e729Hugh Dickins swap_header = kmap(page); 20781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2079ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros maxpages = read_swap_header(p, swap_header, inode); 2080ca8bd38bf6f05481c4155fc444178151884f65d0Cesar Eduardo Barros if (unlikely(!maxpages)) { 20811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds error = -EINVAL; 20821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 20831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2084886bb7e9c3ed0bb3e4a2b1f336d8c6a6e5a4b782Hugh Dickins 208581e33971271ec8603fe696731ff9967afb99e729Hugh Dickins /* OK, set up the swap map and apply the bad block list */ 2086803d0c8351b47b72b8b018457a33b342557b90a2Cesar Eduardo Barros swap_map = vzalloc(maxpages); 208781e33971271ec8603fe696731ff9967afb99e729Hugh Dickins if (!swap_map) { 208881e33971271ec8603fe696731ff9967afb99e729Hugh Dickins error = -ENOMEM; 208981e33971271ec8603fe696731ff9967afb99e729Hugh Dickins goto bad_swap; 209081e33971271ec8603fe696731ff9967afb99e729Hugh Dickins } 20911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20921421ef3cd15b87ef949e965efeb1e527479d3f75Cesar Eduardo Barros error = swap_cgroup_swapon(p->type, maxpages); 20931421ef3cd15b87ef949e965efeb1e527479d3f75Cesar Eduardo Barros if (error) 20941421ef3cd15b87ef949e965efeb1e527479d3f75Cesar Eduardo Barros goto bad_swap; 20951421ef3cd15b87ef949e965efeb1e527479d3f75Cesar Eduardo Barros 2096915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map, 2097915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros maxpages, &span); 2098915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros if (unlikely(nr_extents < 0)) { 2099915d4d7bc0d719f2f0907273c01967d38751c625Cesar Eduardo Barros error = nr_extents; 21001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_swap; 21011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 21021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 21033bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman if (p->bdev) { 21043bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman if (blk_queue_nonrot(bdev_get_queue(p->bdev))) { 21053bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman p->flags |= SWP_SOLIDSTATE; 21063bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman p->cluster_next = 1 + (random32() % p->highest_bit); 21073bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman } 21083399446632739fcd05fd8b272b476a69c6e6d14aHugh Dickins if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD)) 21093bd0f0c763e497c8674b28e3df2732f48683dabdSuresh Jayaraman p->flags |= SWP_DISCARDABLE; 211020137a490f397d9c01fc9fadd83a8d198bda4477Hugh Dickins } 21116a6ba83175c029c7820765bae44692266b29e67aHugh Dickins 2112fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_lock(&swapon_mutex); 211340531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros prio = -1; 211478ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickins if (swap_flags & SWAP_FLAG_PREFER) 211540531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros prio = 211678ecba081224a2db5876b6b81cfed0b78f58adc7Hugh Dickins (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; 211740531542e2832419566c997af0808513f6f2815dCesar Eduardo Barros enable_swap_info(p, prio, swap_map); 2118c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros 2119c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros printk(KERN_INFO "Adding %uk swap on %s. " 2120c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros "Priority:%d extents:%d across:%lluk %s%s\n", 2121c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros p->pages<<(PAGE_SHIFT-10), name, p->prio, 2122c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), 2123c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros (p->flags & SWP_SOLIDSTATE) ? "SS" : "", 2124c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros (p->flags & SWP_DISCARDABLE) ? "D" : ""); 2125c69dbfb84e88503468b6c481aecdb48d76ad5bc6Cesar Eduardo Barros 2126fc0abb1451c64c79ac80665d5ba74450ce274e4dIngo Molnar mutex_unlock(&swapon_mutex); 212766d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers atomic_inc(&proc_poll_event); 212866d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers wake_up_interruptible(&proc_poll_wait); 212966d7dd518ae413a383ab2c6c263cc30617329842Kay Sievers 21309b01c350af4fb00fe2ab66ff9bf16058c50b69bdCesar Eduardo Barros if (S_ISREG(inode->i_mode)) 21319b01c350af4fb00fe2ab66ff9bf16058c50b69bdCesar Eduardo Barros inode->i_flags |= S_SWAPFILE; 21321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds error = 0; 21331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 21341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_swap: 2135bd69010b042a60ca41a890df1b10019e94746c2fCesar Eduardo Barros if (inode && S_ISBLK(inode->i_mode) && p->bdev) { 2136f2090d2df51d7cdb2f952dcfdcd8baaac0aec444Cesar Eduardo Barros set_blocksize(p->bdev, p->old_block_size); 2137f2090d2df51d7cdb2f952dcfdcd8baaac0aec444Cesar Eduardo Barros blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); 21381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 21394cd3bb10ff0b21b77b5a4cd13b4bd36694e054c4Hugh Dickins destroy_swap_extents(p); 2140e8e6c2ec403ecfaa226857d8204344c98fe12b7bCesar Eduardo Barros swap_cgroup_swapoff(p->type); 21415d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 21421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->swap_file = NULL; 21431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds p->flags = 0; 21445d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 21451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds vfree(swap_map); 214652c50567d8ab0a0a87f12cceaa4194967854f0bdMel Gorman if (swap_file) { 21472130781e2aaab66e5a9f2fdc8af35da0153f405cCesar Eduardo Barros if (inode && S_ISREG(inode->i_mode)) { 214852c50567d8ab0a0a87f12cceaa4194967854f0bdMel Gorman mutex_unlock(&inode->i_mutex); 21492130781e2aaab66e5a9f2fdc8af35da0153f405cCesar Eduardo Barros inode = NULL; 21502130781e2aaab66e5a9f2fdc8af35da0153f405cCesar Eduardo Barros } 21511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds filp_close(swap_file, NULL); 215252c50567d8ab0a0a87f12cceaa4194967854f0bdMel Gorman } 21531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout: 21541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (page && !IS_ERR(page)) { 21551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds kunmap(page); 21561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds page_cache_release(page); 21571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 21581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (name) 21591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds putname(name); 21609b01c350af4fb00fe2ab66ff9bf16058c50b69bdCesar Eduardo Barros if (inode && S_ISREG(inode->i_mode)) 21611b1dcc1b57a49136f118a0f16367256ff9994a69Jes Sorensen mutex_unlock(&inode->i_mutex); 21621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return error; 21631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 21641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 21651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsvoid si_swapinfo(struct sysinfo *val) 21661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 2167efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins unsigned int type; 21681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long nr_to_be_unused = 0; 21691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 21705d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 2171efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins for (type = 0; type < nr_swapfiles; type++) { 2172efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins struct swap_info_struct *si = swap_info[type]; 2173efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins 2174efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins if ((si->flags & SWP_USED) && !(si->flags & SWP_WRITEOK)) 2175efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins nr_to_be_unused += si->inuse_pages; 21761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 21771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds val->freeswap = nr_swap_pages + nr_to_be_unused; 21781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds val->totalswap = total_swap_pages + nr_to_be_unused; 21795d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 21801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 21811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 21821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 21831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Verify that a swap entry is valid and increment its swap map count. 21841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 2185355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * Returns error code in following case. 2186355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * - success -> 0 2187355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * - swp_entry is invalid -> EINVAL 2188355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * - swp_entry is migration entry -> EINVAL 2189355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * - swap-cache reference is requested but there is already one. -> EEXIST 2190355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * - swap-cache reference is requested but the entry is not used. -> ENOENT 2191570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * - swap-mapped reference requested but needs continued swap count. -> ENOMEM 21921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 21938d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickinsstatic int __swap_duplicate(swp_entry_t entry, unsigned char usage) 21941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 219573c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins struct swap_info_struct *p; 21961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long offset, type; 21978d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char count; 21988d69aaee80c123b460918816cbfa2e83224c3646Hugh Dickins unsigned char has_cache; 2199253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins int err = -EINVAL; 22001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2201a7420aa54dbf699a5a05feba3c859b6baaa3938cAndi Kleen if (non_swap_entry(entry)) 2202253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins goto out; 22030697212a411c1dae03c27845f2de2f3adb32c331Christoph Lameter 22041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds type = swp_type(entry); 22051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (type >= nr_swapfiles) 22061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto bad_file; 2207efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins p = swap_info[type]; 22081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds offset = swp_offset(entry); 22091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 22105d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 2211355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (unlikely(offset >= p->max)) 2212355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki goto unlock_out; 2213355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 2214253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins count = p->swap_map[offset]; 2215253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins has_cache = count & SWAP_HAS_CACHE; 2216253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins count &= ~SWAP_HAS_CACHE; 2217253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins err = 0; 2218355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 2219253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (usage == SWAP_HAS_CACHE) { 2220355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 2221355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki /* set SWAP_HAS_CACHE if there is no cache and entry is used */ 2222253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins if (!has_cache && count) 2223253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins has_cache = SWAP_HAS_CACHE; 2224253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins else if (has_cache) /* someone else added cache */ 2225253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins err = -EEXIST; 2226253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins else /* no users remaining */ 2227253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins err = -ENOENT; 2228355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki 2229355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki } else if (count || has_cache) { 2230253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 2231570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) 2232570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count += usage; 2233570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) 2234253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins err = -EINVAL; 2235570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins else if (swap_count_continued(p, offset, count)) 2236570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = COUNT_CONTINUED; 2237570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins else 2238570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins err = -ENOMEM; 2239355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki } else 2240253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins err = -ENOENT; /* unused swap entry */ 2241253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 2242253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins p->swap_map[offset] = count | has_cache; 2243253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 2244355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyukiunlock_out: 22455d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 22461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout: 2247253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins return err; 22481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 22491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsbad_file: 22501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); 22511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 22521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 2253253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins 2254355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki/* 2255aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins * Help swapoff by noting that swap entry belongs to shmem/tmpfs 2256aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins * (in which case its reference count is never incremented). 2257aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins */ 2258aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickinsvoid swap_shmem_alloc(swp_entry_t entry) 2259aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins{ 2260aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins __swap_duplicate(entry, SWAP_MAP_SHMEM); 2261aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins} 2262aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins 2263aaa468653b4a0d11c603c48d716f765177a5a9e4Hugh Dickins/* 226408259d58e4fa12ceaece82193c5816152f638ccaHugh Dickins * Increase reference count of swap entry by 1. 226508259d58e4fa12ceaece82193c5816152f638ccaHugh Dickins * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required 226608259d58e4fa12ceaece82193c5816152f638ccaHugh Dickins * but could not be atomically allocated. Returns 0, just as if it succeeded, 226708259d58e4fa12ceaece82193c5816152f638ccaHugh Dickins * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which 226808259d58e4fa12ceaece82193c5816152f638ccaHugh Dickins * might occur if a page table entry has got corrupted. 2269355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki */ 2270570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsint swap_duplicate(swp_entry_t entry) 2271355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki{ 2272570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins int err = 0; 2273570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2274570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins while (!err && __swap_duplicate(entry, 1) == -ENOMEM) 2275570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins err = add_swap_count_continuation(entry, GFP_ATOMIC); 2276570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return err; 2277355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki} 22781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2279cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki/* 2280355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * @entry: swap entry for which we allocate swap cache. 2281355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * 228273c34b6accc8427584f5d7db4d5acb230ed8c912Hugh Dickins * Called when allocating swap cache for existing swap entry, 2283355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * This can return error codes. Returns 0 at success. 2284355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * -EBUSY means there is a swap cache. 2285355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki * Note: return code is different from swap_duplicate(). 2286cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki */ 2287cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyukiint swapcache_prepare(swp_entry_t entry) 2288cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki{ 2289253d553ba75ab26b3e9e2f70cbf6fbf0813f7e86Hugh Dickins return __swap_duplicate(entry, SWAP_HAS_CACHE); 2290cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki} 2291cb4b86ba47bb0937b71fb825b3ed88adf7a190f0KAMEZAWA Hiroyuki 22921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 22935d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins * swap_lock prevents swap_map being freed. Don't grab an extra 22941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * reference on the swaphandle, it doesn't matter if it becomes unused. 22951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 22961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsint valid_swaphandles(swp_entry_t entry, unsigned long *offset) 22971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 22988952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins struct swap_info_struct *si; 22993f9e7949f86dfe2bd9a1ad0604f78e7683c059deHugh Dickins int our_page_cluster = page_cluster; 23008952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins pgoff_t target, toff; 23018952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins pgoff_t base, end; 23028952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins int nr_pages = 0; 23031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 23043f9e7949f86dfe2bd9a1ad0604f78e7683c059deHugh Dickins if (!our_page_cluster) /* no readahead */ 23051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 23068952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins 2307efa90a981bbc891efad96db2a75b5487e00852caHugh Dickins si = swap_info[swp_type(entry)]; 23088952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins target = swp_offset(entry); 23098952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins base = (target >> our_page_cluster) << our_page_cluster; 23108952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins end = base + (1 << our_page_cluster); 23118952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins if (!base) /* first page is swap header */ 23128952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins base++; 23131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 23145d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_lock(&swap_lock); 23158952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins if (end > si->max) /* don't go beyond end of map */ 23168952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins end = si->max; 23178952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins 23188952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins /* Count contiguous allocated slots above our target */ 23198952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins for (toff = target; ++toff < end; nr_pages++) { 23208952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins /* Don't read in free or bad pages */ 23218952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins if (!si->swap_map[toff]) 23228952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins break; 2323355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) 23241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 23258952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins } 23268952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins /* Count contiguous allocated slots below our target */ 23278952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins for (toff = target; --toff >= base; nr_pages++) { 23281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* Don't read in free or bad pages */ 23298952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins if (!si->swap_map[toff]) 23301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 2331355cfa73ddff2fb8fa14e93bd94a057cc022512eKAMEZAWA Hiroyuki if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) 23321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds break; 23338952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins } 23345d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1Hugh Dickins spin_unlock(&swap_lock); 23358952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins 23368952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins /* 23378952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins * Indicate starting offset, and return number of pages to get: 23388952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins * if only 1, say 0, since there's then no readahead to be done. 23398952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins */ 23408952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins *offset = ++toff; 23418952898b0d25223f38daf46b86156fd1c4d17ad0Hugh Dickins return nr_pages? ++nr_pages: 0; 23421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 2343570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2344570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins/* 2345570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * add_swap_count_continuation - called when a swap count is duplicated 2346570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's 2347570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * page of the original vmalloc'ed swap_map, to hold the continuation count 2348570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * (for that entry and for its neighbouring PAGE_SIZE swap entries). Called 2349570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * again when count is duplicated beyond SWAP_MAP_MAX * SWAP_CONT_MAX, etc. 2350570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * 2351570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * These continuation pages are seldom referenced: the common paths all work 2352570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * on the original swap_map, only referring to a continuation page when the 2353570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * low "digit" of a count is incremented or decremented through SWAP_MAP_MAX. 2354570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * 2355570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * add_swap_count_continuation(, GFP_ATOMIC) can be called while holding 2356570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * page table locks; if it fails, add_swap_count_continuation(, GFP_KERNEL) 2357570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * can be called after dropping locks. 2358570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2359570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsint add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) 2360570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins{ 2361570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct swap_info_struct *si; 2362570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *head; 2363570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *page; 2364570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *list_page; 2365570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins pgoff_t offset; 2366570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins unsigned char count; 2367570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2368570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2369570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * When debugging, it's easier to use __GFP_ZERO here; but it's better 2370570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * for latency not to zero a page while GFP_ATOMIC and holding locks. 2371570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2372570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = alloc_page(gfp_mask | __GFP_HIGHMEM); 2373570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2374570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins si = swap_info_get(entry); 2375570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (!si) { 2376570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2377570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * An acceptable race has occurred since the failing 2378570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * __swap_duplicate(): the swap entry has been freed, 2379570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * perhaps even the whole swap_map cleared for swapoff. 2380570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2381570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins goto outer; 2382570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2383570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2384570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins offset = swp_offset(entry); 2385570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = si->swap_map[offset] & ~SWAP_HAS_CACHE; 2386570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2387570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if ((count & ~COUNT_CONTINUED) != SWAP_MAP_MAX) { 2388570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2389570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * The higher the swap count, the more likely it is that tasks 2390570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * will race to add swap count continuation: we need to avoid 2391570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * over-provisioning. 2392570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2393570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins goto out; 2394570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2395570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2396570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (!page) { 2397570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins spin_unlock(&swap_lock); 2398570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return -ENOMEM; 2399570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2400570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2401570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2402570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * We are fortunate that although vmalloc_to_page uses pte_offset_map, 2403570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * no architecture is using highmem pages for kernel pagetables: so it 2404570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * will not corrupt the GFP_ATOMIC caller's atomic pagetable kmaps. 2405570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2406570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins head = vmalloc_to_page(si->swap_map + offset); 2407570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins offset &= ~PAGE_MASK; 2408570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2409570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2410570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * Page allocation does not initialize the page's lru field, 2411570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * but it does always reset its private field. 2412570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2413570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (!page_private(head)) { 2414570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(count & COUNT_CONTINUED); 2415570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins INIT_LIST_HEAD(&head->lru); 2416570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins set_page_private(head, SWP_CONTINUED); 2417570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins si->flags |= SWP_CONTINUED; 2418570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2419570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2420570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins list_for_each_entry(list_page, &head->lru, lru) { 2421570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins unsigned char *map; 2422570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2423570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2424570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * If the previous map said no continuation, but we've found 2425570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * a continuation page, free our allocation and use this one. 2426570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2427570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (!(count & COUNT_CONTINUED)) 2428570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins goto out; 2429570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2430570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(list_page, KM_USER0) + offset; 2431570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = *map; 2432570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2433570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2434570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2435570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * If this continuation count now has some space in it, 2436570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * free our allocation and use this one. 2437570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2438570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) 2439570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins goto out; 2440570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2441570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2442570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins list_add_tail(&page->lru, &head->lru); 2443570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = NULL; /* now it's attached, don't free it */ 2444570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsout: 2445570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins spin_unlock(&swap_lock); 2446570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsouter: 2447570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (page) 2448570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins __free_page(page); 2449570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return 0; 2450570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins} 2451570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2452570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins/* 2453570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * swap_count_continued - when the original swap_map count is incremented 2454570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * from SWAP_MAP_MAX, check if there is already a continuation page to carry 2455570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * into, carry if so, or else fail until a new continuation page is allocated; 2456570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * when the original swap_map count is decremented from 0 with continuation, 2457570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * borrow from the continuation and report whether it still holds more. 2458570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * Called while __swap_duplicate() or swap_entry_free() holds swap_lock. 2459570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2460570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsstatic bool swap_count_continued(struct swap_info_struct *si, 2461570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins pgoff_t offset, unsigned char count) 2462570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins{ 2463570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *head; 2464570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *page; 2465570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins unsigned char *map; 2466570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2467570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins head = vmalloc_to_page(si->swap_map + offset); 2468570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (page_private(head) != SWP_CONTINUED) { 2469570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(count & COUNT_CONTINUED); 2470570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return false; /* need to add count continuation */ 2471570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2472570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2473570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins offset &= ~PAGE_MASK; 2474570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(head->lru.next, struct page, lru); 2475570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2476570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2477570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (count == SWAP_MAP_MAX) /* initial increment from swap_map */ 2478570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins goto init_map; /* jump over SWAP_CONT_MAX checks */ 2479570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2480570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (count == (SWAP_MAP_MAX | COUNT_CONTINUED)) { /* incrementing */ 2481570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2482570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * Think of how you add 1 to 999 2483570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2484570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) { 2485570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2486570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.next, struct page, lru); 2487570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(page == head); 2488570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2489570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2490570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (*map == SWAP_CONT_MAX) { 2491570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2492570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.next, struct page, lru); 2493570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (page == head) 2494570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return false; /* add count continuation */ 2495570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2496570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsinit_map: *map = 0; /* we didn't zero the page */ 2497570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2498570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins *map += 1; 2499570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2500570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.prev, struct page, lru); 2501570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins while (page != head) { 2502570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2503570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins *map = COUNT_CONTINUED; 2504570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2505570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.prev, struct page, lru); 2506570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2507570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return true; /* incremented */ 2508570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2509570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } else { /* decrementing */ 2510570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins /* 2511570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * Think of how you subtract 1 from 1000 2512570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2513570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(count != COUNT_CONTINUED); 2514570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins while (*map == COUNT_CONTINUED) { 2515570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2516570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.next, struct page, lru); 2517570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(page == head); 2518570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2519570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2520570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins BUG_ON(*map == 0); 2521570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins *map -= 1; 2522570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (*map == 0) 2523570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = 0; 2524570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2525570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.prev, struct page, lru); 2526570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins while (page != head) { 2527570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins map = kmap_atomic(page, KM_USER0) + offset; 2528570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins *map = SWAP_CONT_MAX | count; 2529570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins count = COUNT_CONTINUED; 2530570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins kunmap_atomic(map, KM_USER0); 2531570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(page->lru.prev, struct page, lru); 2532570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2533570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins return count == COUNT_CONTINUED; 2534570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2535570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins} 2536570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2537570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins/* 2538570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * free_swap_count_continuations - swapoff free all the continuation pages 2539570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins * appended to the swap_map, after swap_map is quiesced, before vfree'ing it. 2540570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins */ 2541570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickinsstatic void free_swap_count_continuations(struct swap_info_struct *si) 2542570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins{ 2543570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins pgoff_t offset; 2544570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins 2545570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins for (offset = 0; offset < si->max; offset += PAGE_SIZE) { 2546570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *head; 2547570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins head = vmalloc_to_page(si->swap_map + offset); 2548570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins if (page_private(head)) { 2549570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct list_head *this, *next; 2550570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins list_for_each_safe(this, next, &head->lru) { 2551570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins struct page *page; 2552570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins page = list_entry(this, struct page, lru); 2553570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins list_del(this); 2554570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins __free_page(page); 2555570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2556570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2557570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins } 2558570a335b8e22579e2a51a68136d2b1f907a20eecHugh Dickins} 2559