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1/*
2 * mm/fadvise.c
3 *
4 * Copyright (C) 2002, Linus Torvalds
5 *
6 * 11Jan2003 Andrew Morton
7 * Initial version.
8 */
9
10#include <linux/kernel.h>
11#include <linux/file.h>
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/pagemap.h>
15#include <linux/backing-dev.h>
16#include <linux/pagevec.h>
17#include <linux/fadvise.h>
18#include <linux/writeback.h>
19#include <linux/syscalls.h>
20#include <linux/swap.h>
21
22#include <asm/unistd.h>
23
24/*
25 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
26 * deactivate the pages and clear PG_Referenced.
27 */
28SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
29{
30 struct fd f = fdget(fd);
31 struct inode *inode;
32 struct address_space *mapping;
33 struct backing_dev_info *bdi;
34 loff_t endbyte; /* inclusive */
35 pgoff_t start_index;
36 pgoff_t end_index;
37 unsigned long nrpages;
38 int ret = 0;
39
40 if (!f.file)
41 return -EBADF;
42
43 inode = file_inode(f.file);
44 if (S_ISFIFO(inode->i_mode)) {
45 ret = -ESPIPE;
46 goto out;
47 }
48
49 mapping = f.file->f_mapping;
50 if (!mapping || len < 0) {
51 ret = -EINVAL;
52 goto out;
53 }
54
55 if (IS_DAX(inode)) {
56 switch (advice) {
57 case POSIX_FADV_NORMAL:
58 case POSIX_FADV_RANDOM:
59 case POSIX_FADV_SEQUENTIAL:
60 case POSIX_FADV_WILLNEED:
61 case POSIX_FADV_NOREUSE:
62 case POSIX_FADV_DONTNEED:
63 /* no bad return value, but ignore advice */
64 break;
65 default:
66 ret = -EINVAL;
67 }
68 goto out;
69 }
70
71 /* Careful about overflows. Len == 0 means "as much as possible" */
72 endbyte = offset + len;
73 if (!len || endbyte < len)
74 endbyte = -1;
75 else
76 endbyte--; /* inclusive */
77
78 bdi = inode_to_bdi(mapping->host);
79
80 switch (advice) {
81 case POSIX_FADV_NORMAL:
82 f.file->f_ra.ra_pages = bdi->ra_pages;
83 spin_lock(&f.file->f_lock);
84 f.file->f_mode &= ~FMODE_RANDOM;
85 spin_unlock(&f.file->f_lock);
86 break;
87 case POSIX_FADV_RANDOM:
88 spin_lock(&f.file->f_lock);
89 f.file->f_mode |= FMODE_RANDOM;
90 spin_unlock(&f.file->f_lock);
91 break;
92 case POSIX_FADV_SEQUENTIAL:
93 f.file->f_ra.ra_pages = bdi->ra_pages * 2;
94 spin_lock(&f.file->f_lock);
95 f.file->f_mode &= ~FMODE_RANDOM;
96 spin_unlock(&f.file->f_lock);
97 break;
98 case POSIX_FADV_WILLNEED:
99 /* First and last PARTIAL page! */
100 start_index = offset >> PAGE_SHIFT;
101 end_index = endbyte >> PAGE_SHIFT;
102
103 /* Careful about overflow on the "+1" */
104 nrpages = end_index - start_index + 1;
105 if (!nrpages)
106 nrpages = ~0UL;
107
108 /*
109 * Ignore return value because fadvise() shall return
110 * success even if filesystem can't retrieve a hint,
111 */
112 force_page_cache_readahead(mapping, f.file, start_index,
113 nrpages);
114 break;
115 case POSIX_FADV_NOREUSE:
116 break;
117 case POSIX_FADV_DONTNEED:
118 if (!inode_write_congested(mapping->host))
119 __filemap_fdatawrite_range(mapping, offset, endbyte,
120 WB_SYNC_NONE);
121
122 /*
123 * First and last FULL page! Partial pages are deliberately
124 * preserved on the expectation that it is better to preserve
125 * needed memory than to discard unneeded memory.
126 */
127 start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT;
128 end_index = (endbyte >> PAGE_SHIFT);
129
130 if (end_index >= start_index) {
131 unsigned long count = invalidate_mapping_pages(mapping,
132 start_index, end_index);
133
134 /*
135 * If fewer pages were invalidated than expected then
136 * it is possible that some of the pages were on
137 * a per-cpu pagevec for a remote CPU. Drain all
138 * pagevecs and try again.
139 */
140 if (count < (end_index - start_index + 1)) {
141 lru_add_drain_all();
142 invalidate_mapping_pages(mapping, start_index,
143 end_index);
144 }
145 }
146 break;
147 default:
148 ret = -EINVAL;
149 }
150out:
151 fdput(f);
152 return ret;
153}
154
155#ifdef __ARCH_WANT_SYS_FADVISE64
156
157SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice)
158{
159 return sys_fadvise64_64(fd, offset, len, advice);
160}
161
162#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 = -1;
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 if (!inode_write_congested(mapping->host))
113 __filemap_fdatawrite_range(mapping, offset, endbyte,
114 WB_SYNC_NONE);
115
116 /*
117 * First and last FULL page! Partial pages are deliberately
118 * preserved on the expectation that it is better to preserve
119 * needed memory than to discard unneeded memory.
120 */
121 start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT;
122 end_index = (endbyte >> PAGE_SHIFT);
123 /*
124 * The page at end_index will be inclusively discarded according
125 * by invalidate_mapping_pages(), so subtracting 1 from
126 * end_index means we will skip the last page. But if endbyte
127 * is page aligned or is at the end of file, we should not skip
128 * that page - discarding the last page is safe enough.
129 */
130 if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK &&
131 endbyte != inode->i_size - 1) {
132 /* First page is tricky as 0 - 1 = -1, but pgoff_t
133 * is unsigned, so the end_index >= start_index
134 * check below would be true and we'll discard the whole
135 * file cache which is not what was asked.
136 */
137 if (end_index == 0)
138 break;
139
140 end_index--;
141 }
142
143 if (end_index >= start_index) {
144 unsigned long count;
145
146 /*
147 * It's common to FADV_DONTNEED right after
148 * the read or write that instantiates the
149 * pages, in which case there will be some
150 * sitting on the local LRU cache. Try to
151 * avoid the expensive remote drain and the
152 * second cache tree walk below by flushing
153 * them out right away.
154 */
155 lru_add_drain();
156
157 count = invalidate_mapping_pages(mapping,
158 start_index, end_index);
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 (count < (end_index - start_index + 1)) {
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#endif