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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/*
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
21#include <asm/unistd.h>
22
23/*
24 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
25 * deactivate the pages and clear PG_Referenced.
26 */
27SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
28{
29 struct file *file = fget(fd);
30 struct address_space *mapping;
31 struct backing_dev_info *bdi;
32 loff_t endbyte; /* inclusive */
33 pgoff_t start_index;
34 pgoff_t end_index;
35 unsigned long nrpages;
36 int ret = 0;
37
38 if (!file)
39 return -EBADF;
40
41 if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
42 ret = -ESPIPE;
43 goto out;
44 }
45
46 mapping = file->f_mapping;
47 if (!mapping || len < 0) {
48 ret = -EINVAL;
49 goto out;
50 }
51
52 if (mapping->a_ops->get_xip_mem) {
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 ret = -EINVAL;
64 }
65 goto out;
66 }
67
68 /* Careful about overflows. Len == 0 means "as much as possible" */
69 endbyte = offset + len;
70 if (!len || endbyte < len)
71 endbyte = -1;
72 else
73 endbyte--; /* inclusive */
74
75 bdi = mapping->backing_dev_info;
76
77 switch (advice) {
78 case POSIX_FADV_NORMAL:
79 file->f_ra.ra_pages = bdi->ra_pages;
80 spin_lock(&file->f_lock);
81 file->f_mode &= ~FMODE_RANDOM;
82 spin_unlock(&file->f_lock);
83 break;
84 case POSIX_FADV_RANDOM:
85 spin_lock(&file->f_lock);
86 file->f_mode |= FMODE_RANDOM;
87 spin_unlock(&file->f_lock);
88 break;
89 case POSIX_FADV_SEQUENTIAL:
90 file->f_ra.ra_pages = bdi->ra_pages * 2;
91 spin_lock(&file->f_lock);
92 file->f_mode &= ~FMODE_RANDOM;
93 spin_unlock(&file->f_lock);
94 break;
95 case POSIX_FADV_WILLNEED:
96 if (!mapping->a_ops->readpage) {
97 ret = -EINVAL;
98 break;
99 }
100
101 /* First and last PARTIAL page! */
102 start_index = offset >> PAGE_CACHE_SHIFT;
103 end_index = endbyte >> PAGE_CACHE_SHIFT;
104
105 /* Careful about overflow on the "+1" */
106 nrpages = end_index - start_index + 1;
107 if (!nrpages)
108 nrpages = ~0UL;
109
110 ret = force_page_cache_readahead(mapping, file,
111 start_index,
112 nrpages);
113 if (ret > 0)
114 ret = 0;
115 break;
116 case POSIX_FADV_NOREUSE:
117 break;
118 case POSIX_FADV_DONTNEED:
119 if (!bdi_write_congested(mapping->backing_dev_info))
120 filemap_flush(mapping);
121
122 /* First and last FULL page! */
123 start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
124 end_index = (endbyte >> PAGE_CACHE_SHIFT);
125
126 if (end_index >= start_index)
127 invalidate_mapping_pages(mapping, start_index,
128 end_index);
129 break;
130 default:
131 ret = -EINVAL;
132 }
133out:
134 fput(file);
135 return ret;
136}
137#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
138asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice)
139{
140 return SYSC_fadvise64_64((int) fd, offset, len, (int) advice);
141}
142SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64);
143#endif
144
145#ifdef __ARCH_WANT_SYS_FADVISE64
146
147SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice)
148{
149 return sys_fadvise64_64(fd, offset, len, advice);
150}
151#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
152asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice)
153{
154 return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice);
155}
156SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64);
157#endif
158
159#endif