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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * mm/fadvise.c | |
4 | * | |
5 | * Copyright (C) 2002, Linus Torvalds | |
6 | * | |
e1f8e874 | 7 | * 11Jan2003 Andrew Morton |
1da177e4 LT |
8 | * Initial version. |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/file.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/pagemap.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/pagevec.h> | |
18 | #include <linux/fadvise.h> | |
ebcf28e1 | 19 | #include <linux/writeback.h> |
1da177e4 | 20 | #include <linux/syscalls.h> |
67d46b29 | 21 | #include <linux/swap.h> |
1da177e4 LT |
22 | |
23 | #include <asm/unistd.h> | |
24 | ||
cee9a0c4 MWO |
25 | #include "internal.h" |
26 | ||
1da177e4 LT |
27 | /* |
28 | * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could | |
29 | * deactivate the pages and clear PG_Referenced. | |
30 | */ | |
9d5b7c95 | 31 | |
cf1ea059 | 32 | int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice) |
1da177e4 | 33 | { |
e748dcd0 | 34 | struct inode *inode; |
1da177e4 LT |
35 | struct address_space *mapping; |
36 | struct backing_dev_info *bdi; | |
ebcf28e1 | 37 | loff_t endbyte; /* inclusive */ |
1da177e4 LT |
38 | pgoff_t start_index; |
39 | pgoff_t end_index; | |
40 | unsigned long nrpages; | |
1da177e4 | 41 | |
45cd0faa AG |
42 | inode = file_inode(file); |
43 | if (S_ISFIFO(inode->i_mode)) | |
44 | return -ESPIPE; | |
1da177e4 | 45 | |
45cd0faa AG |
46 | mapping = file->f_mapping; |
47 | if (!mapping || len < 0) | |
48 | return -EINVAL; | |
1da177e4 | 49 | |
3a77d214 SB |
50 | bdi = inode_to_bdi(mapping->host); |
51 | ||
52 | if (IS_DAX(inode) || (bdi == &noop_backing_dev_info)) { | |
b5beb1ca MY |
53 | switch (advice) { |
54 | case POSIX_FADV_NORMAL: | |
55 | case POSIX_FADV_RANDOM: | |
56 | case POSIX_FADV_SEQUENTIAL: | |
57 | case POSIX_FADV_WILLNEED: | |
58 | case POSIX_FADV_NOREUSE: | |
59 | case POSIX_FADV_DONTNEED: | |
60 | /* no bad return value, but ignore advice */ | |
61 | break; | |
62 | default: | |
45cd0faa | 63 | return -EINVAL; |
b5beb1ca | 64 | } |
45cd0faa | 65 | return 0; |
b5beb1ca | 66 | } |
fe77ba6f | 67 | |
a718e28f AR |
68 | /* |
69 | * Careful about overflows. Len == 0 means "as much as possible". Use | |
70 | * unsigned math because signed overflows are undefined and UBSan | |
71 | * complains. | |
72 | */ | |
73 | endbyte = (u64)offset + (u64)len; | |
1da177e4 | 74 | if (!len || endbyte < len) |
3cd629e5 | 75 | endbyte = LLONG_MAX; |
ebcf28e1 AM |
76 | else |
77 | endbyte--; /* inclusive */ | |
1da177e4 | 78 | |
1da177e4 LT |
79 | switch (advice) { |
80 | case POSIX_FADV_NORMAL: | |
45cd0faa AG |
81 | file->f_ra.ra_pages = bdi->ra_pages; |
82 | spin_lock(&file->f_lock); | |
17e81022 | 83 | file->f_mode &= ~(FMODE_RANDOM | FMODE_NOREUSE); |
45cd0faa | 84 | spin_unlock(&file->f_lock); |
1da177e4 LT |
85 | break; |
86 | case POSIX_FADV_RANDOM: | |
45cd0faa AG |
87 | spin_lock(&file->f_lock); |
88 | file->f_mode |= FMODE_RANDOM; | |
89 | spin_unlock(&file->f_lock); | |
1da177e4 LT |
90 | break; |
91 | case POSIX_FADV_SEQUENTIAL: | |
45cd0faa AG |
92 | file->f_ra.ra_pages = bdi->ra_pages * 2; |
93 | spin_lock(&file->f_lock); | |
94 | file->f_mode &= ~FMODE_RANDOM; | |
95 | spin_unlock(&file->f_lock); | |
1da177e4 LT |
96 | break; |
97 | case POSIX_FADV_WILLNEED: | |
1da177e4 | 98 | /* First and last PARTIAL page! */ |
09cbfeaf KS |
99 | start_index = offset >> PAGE_SHIFT; |
100 | end_index = endbyte >> PAGE_SHIFT; | |
1da177e4 LT |
101 | |
102 | /* Careful about overflow on the "+1" */ | |
103 | nrpages = end_index - start_index + 1; | |
104 | if (!nrpages) | |
105 | nrpages = ~0UL; | |
3d3727cd | 106 | |
45cd0faa | 107 | force_page_cache_readahead(mapping, file, start_index, nrpages); |
1da177e4 | 108 | break; |
60c371bc | 109 | case POSIX_FADV_NOREUSE: |
17e81022 YZ |
110 | spin_lock(&file->f_lock); |
111 | file->f_mode |= FMODE_NOREUSE; | |
112 | spin_unlock(&file->f_lock); | |
60c371bc | 113 | break; |
1da177e4 | 114 | case POSIX_FADV_DONTNEED: |
fe55d563 N |
115 | __filemap_fdatawrite_range(mapping, offset, endbyte, |
116 | WB_SYNC_NONE); | |
1da177e4 | 117 | |
441c228f MG |
118 | /* |
119 | * First and last FULL page! Partial pages are deliberately | |
120 | * preserved on the expectation that it is better to preserve | |
121 | * needed memory than to discard unneeded memory. | |
122 | */ | |
09cbfeaf KS |
123 | start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT; |
124 | end_index = (endbyte >> PAGE_SHIFT); | |
a7ab400d | 125 | /* |
126 | * The page at end_index will be inclusively discarded according | |
127 | * by invalidate_mapping_pages(), so subtracting 1 from | |
128 | * end_index means we will skip the last page. But if endbyte | |
129 | * is page aligned or is at the end of file, we should not skip | |
130 | * that page - discarding the last page is safe enough. | |
131 | */ | |
132 | if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK && | |
133 | endbyte != inode->i_size - 1) { | |
18aba41c OD |
134 | /* First page is tricky as 0 - 1 = -1, but pgoff_t |
135 | * is unsigned, so the end_index >= start_index | |
136 | * check below would be true and we'll discard the whole | |
137 | * file cache which is not what was asked. | |
138 | */ | |
139 | if (end_index == 0) | |
140 | break; | |
141 | ||
142 | end_index--; | |
143 | } | |
1da177e4 | 144 | |
67d46b29 | 145 | if (end_index >= start_index) { |
eb1d7a65 | 146 | unsigned long nr_pagevec = 0; |
4dd72b4a JW |
147 | |
148 | /* | |
149 | * It's common to FADV_DONTNEED right after | |
150 | * the read or write that instantiates the | |
151 | * pages, in which case there will be some | |
152 | * sitting on the local LRU cache. Try to | |
153 | * avoid the expensive remote drain and the | |
154 | * second cache tree walk below by flushing | |
155 | * them out right away. | |
156 | */ | |
157 | lru_add_drain(); | |
158 | ||
eb1d7a65 YS |
159 | invalidate_mapping_pagevec(mapping, |
160 | start_index, end_index, | |
161 | &nr_pagevec); | |
67d46b29 MG |
162 | |
163 | /* | |
164 | * If fewer pages were invalidated than expected then | |
165 | * it is possible that some of the pages were on | |
166 | * a per-cpu pagevec for a remote CPU. Drain all | |
167 | * pagevecs and try again. | |
168 | */ | |
eb1d7a65 | 169 | if (nr_pagevec) { |
67d46b29 MG |
170 | lru_add_drain_all(); |
171 | invalidate_mapping_pages(mapping, start_index, | |
ebcf28e1 | 172 | end_index); |
67d46b29 MG |
173 | } |
174 | } | |
ebcf28e1 | 175 | break; |
1da177e4 | 176 | default: |
45cd0faa | 177 | return -EINVAL; |
1da177e4 | 178 | } |
45cd0faa AG |
179 | return 0; |
180 | } | |
cf1ea059 | 181 | EXPORT_SYMBOL(generic_fadvise); |
45cd0faa AG |
182 | |
183 | int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice) | |
184 | { | |
185 | if (file->f_op->fadvise) | |
186 | return file->f_op->fadvise(file, offset, len, advice); | |
187 | ||
188 | return generic_fadvise(file, offset, len, advice); | |
189 | } | |
190 | EXPORT_SYMBOL(vfs_fadvise); | |
191 | ||
3d8f7615 AG |
192 | #ifdef CONFIG_ADVISE_SYSCALLS |
193 | ||
45cd0faa AG |
194 | int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) |
195 | { | |
196 | struct fd f = fdget(fd); | |
197 | int ret; | |
198 | ||
199 | if (!f.file) | |
200 | return -EBADF; | |
201 | ||
202 | ret = vfs_fadvise(f.file, offset, len, advice); | |
203 | ||
2903ff01 | 204 | fdput(f); |
1da177e4 LT |
205 | return ret; |
206 | } | |
207 | ||
9d5b7c95 DB |
208 | SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice) |
209 | { | |
210 | return ksys_fadvise64_64(fd, offset, len, advice); | |
211 | } | |
212 | ||
1da177e4 LT |
213 | #ifdef __ARCH_WANT_SYS_FADVISE64 |
214 | ||
4a0fd5bf | 215 | SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice) |
1da177e4 | 216 | { |
9d5b7c95 | 217 | return ksys_fadvise64_64(fd, offset, len, advice); |
1da177e4 LT |
218 | } |
219 | ||
59c10c52 GR |
220 | #endif |
221 | ||
222 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FADVISE64_64) | |
223 | ||
224 | COMPAT_SYSCALL_DEFINE6(fadvise64_64, int, fd, compat_arg_u64_dual(offset), | |
225 | compat_arg_u64_dual(len), int, advice) | |
226 | { | |
227 | return ksys_fadvise64_64(fd, compat_arg_u64_glue(offset), | |
228 | compat_arg_u64_glue(len), advice); | |
229 | } | |
230 | ||
1da177e4 | 231 | #endif |
3d8f7615 | 232 | #endif |