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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 LT |
74 | if (!len || endbyte < len) |
75 | endbyte = -1; | |
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); | |
83 | file->f_mode &= ~FMODE_RANDOM; | |
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 AM |
109 | case POSIX_FADV_NOREUSE: |
110 | break; | |
1da177e4 | 111 | case POSIX_FADV_DONTNEED: |
fe55d563 N |
112 | __filemap_fdatawrite_range(mapping, offset, endbyte, |
113 | WB_SYNC_NONE); | |
1da177e4 | 114 | |
441c228f MG |
115 | /* |
116 | * First and last FULL page! Partial pages are deliberately | |
117 | * preserved on the expectation that it is better to preserve | |
118 | * needed memory than to discard unneeded memory. | |
119 | */ | |
09cbfeaf KS |
120 | start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT; |
121 | end_index = (endbyte >> PAGE_SHIFT); | |
a7ab400d | 122 | /* |
123 | * The page at end_index will be inclusively discarded according | |
124 | * by invalidate_mapping_pages(), so subtracting 1 from | |
125 | * end_index means we will skip the last page. But if endbyte | |
126 | * is page aligned or is at the end of file, we should not skip | |
127 | * that page - discarding the last page is safe enough. | |
128 | */ | |
129 | if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK && | |
130 | endbyte != inode->i_size - 1) { | |
18aba41c OD |
131 | /* First page is tricky as 0 - 1 = -1, but pgoff_t |
132 | * is unsigned, so the end_index >= start_index | |
133 | * check below would be true and we'll discard the whole | |
134 | * file cache which is not what was asked. | |
135 | */ | |
136 | if (end_index == 0) | |
137 | break; | |
138 | ||
139 | end_index--; | |
140 | } | |
1da177e4 | 141 | |
67d46b29 | 142 | if (end_index >= start_index) { |
eb1d7a65 | 143 | unsigned long nr_pagevec = 0; |
4dd72b4a JW |
144 | |
145 | /* | |
146 | * It's common to FADV_DONTNEED right after | |
147 | * the read or write that instantiates the | |
148 | * pages, in which case there will be some | |
149 | * sitting on the local LRU cache. Try to | |
150 | * avoid the expensive remote drain and the | |
151 | * second cache tree walk below by flushing | |
152 | * them out right away. | |
153 | */ | |
154 | lru_add_drain(); | |
155 | ||
eb1d7a65 YS |
156 | invalidate_mapping_pagevec(mapping, |
157 | start_index, end_index, | |
158 | &nr_pagevec); | |
67d46b29 MG |
159 | |
160 | /* | |
161 | * If fewer pages were invalidated than expected then | |
162 | * it is possible that some of the pages were on | |
163 | * a per-cpu pagevec for a remote CPU. Drain all | |
164 | * pagevecs and try again. | |
165 | */ | |
eb1d7a65 | 166 | if (nr_pagevec) { |
67d46b29 MG |
167 | lru_add_drain_all(); |
168 | invalidate_mapping_pages(mapping, start_index, | |
ebcf28e1 | 169 | end_index); |
67d46b29 MG |
170 | } |
171 | } | |
ebcf28e1 | 172 | break; |
1da177e4 | 173 | default: |
45cd0faa | 174 | return -EINVAL; |
1da177e4 | 175 | } |
45cd0faa AG |
176 | return 0; |
177 | } | |
cf1ea059 | 178 | EXPORT_SYMBOL(generic_fadvise); |
45cd0faa AG |
179 | |
180 | int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice) | |
181 | { | |
182 | if (file->f_op->fadvise) | |
183 | return file->f_op->fadvise(file, offset, len, advice); | |
184 | ||
185 | return generic_fadvise(file, offset, len, advice); | |
186 | } | |
187 | EXPORT_SYMBOL(vfs_fadvise); | |
188 | ||
3d8f7615 AG |
189 | #ifdef CONFIG_ADVISE_SYSCALLS |
190 | ||
45cd0faa AG |
191 | int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) |
192 | { | |
193 | struct fd f = fdget(fd); | |
194 | int ret; | |
195 | ||
196 | if (!f.file) | |
197 | return -EBADF; | |
198 | ||
199 | ret = vfs_fadvise(f.file, offset, len, advice); | |
200 | ||
2903ff01 | 201 | fdput(f); |
1da177e4 LT |
202 | return ret; |
203 | } | |
204 | ||
9d5b7c95 DB |
205 | SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice) |
206 | { | |
207 | return ksys_fadvise64_64(fd, offset, len, advice); | |
208 | } | |
209 | ||
1da177e4 LT |
210 | #ifdef __ARCH_WANT_SYS_FADVISE64 |
211 | ||
4a0fd5bf | 212 | SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice) |
1da177e4 | 213 | { |
9d5b7c95 | 214 | return ksys_fadvise64_64(fd, offset, len, advice); |
1da177e4 LT |
215 | } |
216 | ||
217 | #endif | |
3d8f7615 | 218 | #endif |