1#include <linux/ceph/ceph_debug.h>
2
3#include <linux/module.h>
4#include <linux/sched.h>
5#include <linux/slab.h>
6#include <linux/file.h>
7#include <linux/namei.h>
8#include <linux/writeback.h>
9
10#include <linux/ceph/libceph.h>
11
12/*
13 * build a vector of user pages
14 */
15struct page **ceph_get_direct_page_vector(const void __user *data,
16					  int num_pages, bool write_page)
17{
18	struct page **pages;
19	int got = 0;
20	int rc = 0;
21
22	pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);
23	if (!pages)
24		return ERR_PTR(-ENOMEM);
25
26	down_read(&current->mm->mmap_sem);
27	while (got < num_pages) {
28		rc = get_user_pages(current, current->mm,
29		    (unsigned long)data + ((unsigned long)got * PAGE_SIZE),
30		    num_pages - got, write_page, 0, pages + got, NULL);
31		if (rc < 0)
32			break;
33		BUG_ON(rc == 0);
34		got += rc;
35	}
36	up_read(&current->mm->mmap_sem);
37	if (rc < 0)
38		goto fail;
39	return pages;
40
41fail:
42	ceph_put_page_vector(pages, got, false);
43	return ERR_PTR(rc);
44}
45EXPORT_SYMBOL(ceph_get_direct_page_vector);
46
47void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
48{
49	int i;
50
51	for (i = 0; i < num_pages; i++) {
52		if (dirty)
53			set_page_dirty_lock(pages[i]);
54		put_page(pages[i]);
55	}
56	kfree(pages);
57}
58EXPORT_SYMBOL(ceph_put_page_vector);
59
60void ceph_release_page_vector(struct page **pages, int num_pages)
61{
62	int i;
63
64	for (i = 0; i < num_pages; i++)
65		__free_pages(pages[i], 0);
66	kfree(pages);
67}
68EXPORT_SYMBOL(ceph_release_page_vector);
69
70/*
71 * allocate a vector new pages
72 */
73struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags)
74{
75	struct page **pages;
76	int i;
77
78	pages = kmalloc(sizeof(*pages) * num_pages, flags);
79	if (!pages)
80		return ERR_PTR(-ENOMEM);
81	for (i = 0; i < num_pages; i++) {
82		pages[i] = __page_cache_alloc(flags);
83		if (pages[i] == NULL) {
84			ceph_release_page_vector(pages, i);
85			return ERR_PTR(-ENOMEM);
86		}
87	}
88	return pages;
89}
90EXPORT_SYMBOL(ceph_alloc_page_vector);
91
92/*
93 * copy user data into a page vector
94 */
95int ceph_copy_user_to_page_vector(struct page **pages,
96					 const void __user *data,
97					 loff_t off, size_t len)
98{
99	int i = 0;
100	int po = off & ~PAGE_CACHE_MASK;
101	int left = len;
102	int l, bad;
103
104	while (left > 0) {
105		l = min_t(int, PAGE_CACHE_SIZE-po, left);
106		bad = copy_from_user(page_address(pages[i]) + po, data, l);
107		if (bad == l)
108			return -EFAULT;
109		data += l - bad;
110		left -= l - bad;
111		po += l - bad;
112		if (po == PAGE_CACHE_SIZE) {
113			po = 0;
114			i++;
115		}
116	}
117	return len;
118}
119EXPORT_SYMBOL(ceph_copy_user_to_page_vector);
120
121void ceph_copy_to_page_vector(struct page **pages,
122				    const void *data,
123				    loff_t off, size_t len)
124{
125	int i = 0;
126	size_t po = off & ~PAGE_CACHE_MASK;
127	size_t left = len;
128
129	while (left > 0) {
130		size_t l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
131
132		memcpy(page_address(pages[i]) + po, data, l);
133		data += l;
134		left -= l;
135		po += l;
136		if (po == PAGE_CACHE_SIZE) {
137			po = 0;
138			i++;
139		}
140	}
141}
142EXPORT_SYMBOL(ceph_copy_to_page_vector);
143
144void ceph_copy_from_page_vector(struct page **pages,
145				    void *data,
146				    loff_t off, size_t len)
147{
148	int i = 0;
149	size_t po = off & ~PAGE_CACHE_MASK;
150	size_t left = len;
151
152	while (left > 0) {
153		size_t l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
154
155		memcpy(data, page_address(pages[i]) + po, l);
156		data += l;
157		left -= l;
158		po += l;
159		if (po == PAGE_CACHE_SIZE) {
160			po = 0;
161			i++;
162		}
163	}
164}
165EXPORT_SYMBOL(ceph_copy_from_page_vector);
166
167/*
168 * copy user data from a page vector into a user pointer
169 */
170int ceph_copy_page_vector_to_user(struct page **pages,
171					 void __user *data,
172					 loff_t off, size_t len)
173{
174	int i = 0;
175	int po = off & ~PAGE_CACHE_MASK;
176	int left = len;
177	int l, bad;
178
179	while (left > 0) {
180		l = min_t(int, left, PAGE_CACHE_SIZE-po);
181		bad = copy_to_user(data, page_address(pages[i]) + po, l);
182		if (bad == l)
183			return -EFAULT;
184		data += l - bad;
185		left -= l - bad;
186		if (po) {
187			po += l - bad;
188			if (po == PAGE_CACHE_SIZE)
189				po = 0;
190		}
191		i++;
192	}
193	return len;
194}
195EXPORT_SYMBOL(ceph_copy_page_vector_to_user);
196
197/*
198 * Zero an extent within a page vector.  Offset is relative to the
199 * start of the first page.
200 */
201void ceph_zero_page_vector_range(int off, int len, struct page **pages)
202{
203	int i = off >> PAGE_CACHE_SHIFT;
204
205	off &= ~PAGE_CACHE_MASK;
206
207	dout("zero_page_vector_page %u~%u\n", off, len);
208
209	/* leading partial page? */
210	if (off) {
211		int end = min((int)PAGE_CACHE_SIZE, off + len);
212		dout("zeroing %d %p head from %d\n", i, pages[i],
213		     (int)off);
214		zero_user_segment(pages[i], off, end);
215		len -= (end - off);
216		i++;
217	}
218	while (len >= PAGE_CACHE_SIZE) {
219		dout("zeroing %d %p len=%d\n", i, pages[i], len);
220		zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE);
221		len -= PAGE_CACHE_SIZE;
222		i++;
223	}
224	/* trailing partial page? */
225	if (len) {
226		dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
227		zero_user_segment(pages[i], 0, len);
228	}
229}
230EXPORT_SYMBOL(ceph_zero_page_vector_range);
231
232