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3d14c5d2 YS |
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 | */ | |
15 | struct page **ceph_get_direct_page_vector(const char __user *data, | |
16 | int num_pages, | |
17 | loff_t off, size_t len) | |
18 | { | |
19 | struct page **pages; | |
20 | int rc; | |
21 | ||
22 | pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS); | |
23 | if (!pages) | |
24 | return ERR_PTR(-ENOMEM); | |
25 | ||
26 | down_read(¤t->mm->mmap_sem); | |
27 | rc = get_user_pages(current, current->mm, (unsigned long)data, | |
28 | num_pages, 0, 0, pages, NULL); | |
29 | up_read(¤t->mm->mmap_sem); | |
30 | if (rc < 0) | |
31 | goto fail; | |
32 | return pages; | |
33 | ||
34 | fail: | |
35 | kfree(pages); | |
36 | return ERR_PTR(rc); | |
37 | } | |
38 | EXPORT_SYMBOL(ceph_get_direct_page_vector); | |
39 | ||
40 | void ceph_put_page_vector(struct page **pages, int num_pages) | |
41 | { | |
42 | int i; | |
43 | ||
44 | for (i = 0; i < num_pages; i++) | |
45 | put_page(pages[i]); | |
46 | kfree(pages); | |
47 | } | |
48 | EXPORT_SYMBOL(ceph_put_page_vector); | |
49 | ||
50 | void ceph_release_page_vector(struct page **pages, int num_pages) | |
51 | { | |
52 | int i; | |
53 | ||
54 | for (i = 0; i < num_pages; i++) | |
55 | __free_pages(pages[i], 0); | |
56 | kfree(pages); | |
57 | } | |
58 | EXPORT_SYMBOL(ceph_release_page_vector); | |
59 | ||
60 | /* | |
61 | * allocate a vector new pages | |
62 | */ | |
63 | struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags) | |
64 | { | |
65 | struct page **pages; | |
66 | int i; | |
67 | ||
68 | pages = kmalloc(sizeof(*pages) * num_pages, flags); | |
69 | if (!pages) | |
70 | return ERR_PTR(-ENOMEM); | |
71 | for (i = 0; i < num_pages; i++) { | |
72 | pages[i] = __page_cache_alloc(flags); | |
73 | if (pages[i] == NULL) { | |
74 | ceph_release_page_vector(pages, i); | |
75 | return ERR_PTR(-ENOMEM); | |
76 | } | |
77 | } | |
78 | return pages; | |
79 | } | |
80 | EXPORT_SYMBOL(ceph_alloc_page_vector); | |
81 | ||
82 | /* | |
83 | * copy user data into a page vector | |
84 | */ | |
85 | int ceph_copy_user_to_page_vector(struct page **pages, | |
86 | const char __user *data, | |
87 | loff_t off, size_t len) | |
88 | { | |
89 | int i = 0; | |
90 | int po = off & ~PAGE_CACHE_MASK; | |
91 | int left = len; | |
92 | int l, bad; | |
93 | ||
94 | while (left > 0) { | |
95 | l = min_t(int, PAGE_CACHE_SIZE-po, left); | |
96 | bad = copy_from_user(page_address(pages[i]) + po, data, l); | |
97 | if (bad == l) | |
98 | return -EFAULT; | |
99 | data += l - bad; | |
100 | left -= l - bad; | |
101 | po += l - bad; | |
102 | if (po == PAGE_CACHE_SIZE) { | |
103 | po = 0; | |
104 | i++; | |
105 | } | |
106 | } | |
107 | return len; | |
108 | } | |
109 | EXPORT_SYMBOL(ceph_copy_user_to_page_vector); | |
110 | ||
111 | int ceph_copy_to_page_vector(struct page **pages, | |
112 | const char *data, | |
113 | loff_t off, size_t len) | |
114 | { | |
115 | int i = 0; | |
116 | size_t po = off & ~PAGE_CACHE_MASK; | |
117 | size_t left = len; | |
118 | size_t l; | |
119 | ||
120 | while (left > 0) { | |
121 | l = min_t(size_t, PAGE_CACHE_SIZE-po, left); | |
122 | memcpy(page_address(pages[i]) + po, data, l); | |
123 | data += l; | |
124 | left -= l; | |
125 | po += l; | |
126 | if (po == PAGE_CACHE_SIZE) { | |
127 | po = 0; | |
128 | i++; | |
129 | } | |
130 | } | |
131 | return len; | |
132 | } | |
133 | EXPORT_SYMBOL(ceph_copy_to_page_vector); | |
134 | ||
135 | int ceph_copy_from_page_vector(struct page **pages, | |
136 | char *data, | |
137 | loff_t off, size_t len) | |
138 | { | |
139 | int i = 0; | |
140 | size_t po = off & ~PAGE_CACHE_MASK; | |
141 | size_t left = len; | |
142 | size_t l; | |
143 | ||
144 | while (left > 0) { | |
145 | l = min_t(size_t, PAGE_CACHE_SIZE-po, left); | |
146 | memcpy(data, page_address(pages[i]) + po, l); | |
147 | data += l; | |
148 | left -= l; | |
149 | po += l; | |
150 | if (po == PAGE_CACHE_SIZE) { | |
151 | po = 0; | |
152 | i++; | |
153 | } | |
154 | } | |
155 | return len; | |
156 | } | |
157 | EXPORT_SYMBOL(ceph_copy_from_page_vector); | |
158 | ||
159 | /* | |
160 | * copy user data from a page vector into a user pointer | |
161 | */ | |
162 | int ceph_copy_page_vector_to_user(struct page **pages, | |
163 | char __user *data, | |
164 | loff_t off, size_t len) | |
165 | { | |
166 | int i = 0; | |
167 | int po = off & ~PAGE_CACHE_MASK; | |
168 | int left = len; | |
169 | int l, bad; | |
170 | ||
171 | while (left > 0) { | |
172 | l = min_t(int, left, PAGE_CACHE_SIZE-po); | |
173 | bad = copy_to_user(data, page_address(pages[i]) + po, l); | |
174 | if (bad == l) | |
175 | return -EFAULT; | |
176 | data += l - bad; | |
177 | left -= l - bad; | |
178 | if (po) { | |
179 | po += l - bad; | |
180 | if (po == PAGE_CACHE_SIZE) | |
181 | po = 0; | |
182 | } | |
183 | i++; | |
184 | } | |
185 | return len; | |
186 | } | |
187 | EXPORT_SYMBOL(ceph_copy_page_vector_to_user); | |
188 | ||
189 | /* | |
190 | * Zero an extent within a page vector. Offset is relative to the | |
191 | * start of the first page. | |
192 | */ | |
193 | void ceph_zero_page_vector_range(int off, int len, struct page **pages) | |
194 | { | |
195 | int i = off >> PAGE_CACHE_SHIFT; | |
196 | ||
197 | off &= ~PAGE_CACHE_MASK; | |
198 | ||
199 | dout("zero_page_vector_page %u~%u\n", off, len); | |
200 | ||
201 | /* leading partial page? */ | |
202 | if (off) { | |
203 | int end = min((int)PAGE_CACHE_SIZE, off + len); | |
204 | dout("zeroing %d %p head from %d\n", i, pages[i], | |
205 | (int)off); | |
206 | zero_user_segment(pages[i], off, end); | |
207 | len -= (end - off); | |
208 | i++; | |
209 | } | |
210 | while (len >= PAGE_CACHE_SIZE) { | |
211 | dout("zeroing %d %p len=%d\n", i, pages[i], len); | |
212 | zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE); | |
213 | len -= PAGE_CACHE_SIZE; | |
214 | i++; | |
215 | } | |
216 | /* trailing partial page? */ | |
217 | if (len) { | |
218 | dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len); | |
219 | zero_user_segment(pages[i], 0, len); | |
220 | } | |
221 | } | |
222 | EXPORT_SYMBOL(ceph_zero_page_vector_range); | |
223 |