Merge branch 'core/urgent' into core/entry
[platform/kernel/linux-rpi.git] / mm / fadvise.c
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
32 int 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 nr_pagevec = 0;
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                         invalidate_mapping_pagevec(mapping,
158                                                 start_index, end_index,
159                                                 &nr_pagevec);
160
161                         /*
162                          * If fewer pages were invalidated than expected then
163                          * it is possible that some of the pages were on
164                          * a per-cpu pagevec for a remote CPU. Drain all
165                          * pagevecs and try again.
166                          */
167                         if (nr_pagevec) {
168                                 lru_add_drain_all();
169                                 invalidate_mapping_pages(mapping, start_index,
170                                                 end_index);
171                         }
172                 }
173                 break;
174         default:
175                 return -EINVAL;
176         }
177         return 0;
178 }
179 EXPORT_SYMBOL(generic_fadvise);
180
181 int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
182 {
183         if (file->f_op->fadvise)
184                 return file->f_op->fadvise(file, offset, len, advice);
185
186         return generic_fadvise(file, offset, len, advice);
187 }
188 EXPORT_SYMBOL(vfs_fadvise);
189
190 #ifdef CONFIG_ADVISE_SYSCALLS
191
192 int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
193 {
194         struct fd f = fdget(fd);
195         int ret;
196
197         if (!f.file)
198                 return -EBADF;
199
200         ret = vfs_fadvise(f.file, offset, len, advice);
201
202         fdput(f);
203         return ret;
204 }
205
206 SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
207 {
208         return ksys_fadvise64_64(fd, offset, len, advice);
209 }
210
211 #ifdef __ARCH_WANT_SYS_FADVISE64
212
213 SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice)
214 {
215         return ksys_fadvise64_64(fd, offset, len, advice);
216 }
217
218 #endif
219 #endif