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