pagelist.c revision 3d14c5d2b6e15c21d8e5467dc62d33127c23a644 
1
2#include <linux/module.h>
3#include <linux/gfp.h>
4#include <linux/pagemap.h>
5#include <linux/highmem.h>
6#include <linux/ceph/pagelist.h>
7
8static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
9{
10	struct page *page = list_entry(pl->head.prev, struct page,
11				       lru);
12	kunmap(page);
13}
14
15int ceph_pagelist_release(struct ceph_pagelist *pl)
16{
17	if (pl->mapped_tail)
18		ceph_pagelist_unmap_tail(pl);
19
20	while (!list_empty(&pl->head)) {
21		struct page *page = list_first_entry(&pl->head, struct page,
22						     lru);
23		list_del(&page->lru);
24		__free_page(page);
25	}
26	return 0;
27}
28EXPORT_SYMBOL(ceph_pagelist_release);
29
30static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
31{
32	struct page *page = __page_cache_alloc(GFP_NOFS);
33	if (!page)
34		return -ENOMEM;
35	pl->room += PAGE_SIZE;
36	list_add_tail(&page->lru, &pl->head);
37	if (pl->mapped_tail)
38		ceph_pagelist_unmap_tail(pl);
39	pl->mapped_tail = kmap(page);
40	return 0;
41}
42
43int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
44{
45	while (pl->room < len) {
46		size_t bit = pl->room;
47		int ret;
48
49		memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
50		       buf, bit);
51		pl->length += bit;
52		pl->room -= bit;
53		buf += bit;
54		len -= bit;
55		ret = ceph_pagelist_addpage(pl);
56		if (ret)
57			return ret;
58	}
59
60	memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
61	pl->length += len;
62	pl->room -= len;
63	return 0;
64}
65EXPORT_SYMBOL(ceph_pagelist_append);
66