1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PAGEMAP_H
3 #define _LINUX_PAGEMAP_H
4
5 /*
6 * Copyright 1995 Linus Torvalds
7 */
8 #include <linux/mm.h>
9 #include <linux/fs.h>
10 #include <linux/list.h>
11 #include <linux/highmem.h>
12 #include <linux/compiler.h>
13 #include <linux/uaccess.h>
14 #include <linux/gfp.h>
15 #include <linux/bitops.h>
16 #include <linux/hardirq.h> /* for in_interrupt() */
17 #include <linux/hugetlb_inline.h>
18
19 struct folio_batch;
20
21 unsigned long invalidate_mapping_pages(struct address_space *mapping,
22 pgoff_t start, pgoff_t end);
23
invalidate_remote_inode(struct inode * inode)24 static inline void invalidate_remote_inode(struct inode *inode)
25 {
26 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
27 S_ISLNK(inode->i_mode))
28 invalidate_mapping_pages(inode->i_mapping, 0, -1);
29 }
30 int invalidate_inode_pages2(struct address_space *mapping);
31 int invalidate_inode_pages2_range(struct address_space *mapping,
32 pgoff_t start, pgoff_t end);
33 int write_inode_now(struct inode *, int sync);
34 int filemap_fdatawrite(struct address_space *);
35 int filemap_flush(struct address_space *);
36 int filemap_fdatawait_keep_errors(struct address_space *mapping);
37 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
38 int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
39 loff_t start_byte, loff_t end_byte);
40
filemap_fdatawait(struct address_space * mapping)41 static inline int filemap_fdatawait(struct address_space *mapping)
42 {
43 return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
44 }
45
46 bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend);
47 int filemap_write_and_wait_range(struct address_space *mapping,
48 loff_t lstart, loff_t lend);
49 int __filemap_fdatawrite_range(struct address_space *mapping,
50 loff_t start, loff_t end, int sync_mode);
51 int filemap_fdatawrite_range(struct address_space *mapping,
52 loff_t start, loff_t end);
53 int filemap_check_errors(struct address_space *mapping);
54 void __filemap_set_wb_err(struct address_space *mapping, int err);
55 int filemap_fdatawrite_wbc(struct address_space *mapping,
56 struct writeback_control *wbc);
57
filemap_write_and_wait(struct address_space * mapping)58 static inline int filemap_write_and_wait(struct address_space *mapping)
59 {
60 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX);
61 }
62
63 /**
64 * filemap_set_wb_err - set a writeback error on an address_space
65 * @mapping: mapping in which to set writeback error
66 * @err: error to be set in mapping
67 *
68 * When writeback fails in some way, we must record that error so that
69 * userspace can be informed when fsync and the like are called. We endeavor
70 * to report errors on any file that was open at the time of the error. Some
71 * internal callers also need to know when writeback errors have occurred.
72 *
73 * When a writeback error occurs, most filesystems will want to call
74 * filemap_set_wb_err to record the error in the mapping so that it will be
75 * automatically reported whenever fsync is called on the file.
76 */
filemap_set_wb_err(struct address_space * mapping,int err)77 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
78 {
79 /* Fastpath for common case of no error */
80 if (unlikely(err))
81 __filemap_set_wb_err(mapping, err);
82 }
83
84 /**
85 * filemap_check_wb_err - has an error occurred since the mark was sampled?
86 * @mapping: mapping to check for writeback errors
87 * @since: previously-sampled errseq_t
88 *
89 * Grab the errseq_t value from the mapping, and see if it has changed "since"
90 * the given value was sampled.
91 *
92 * If it has then report the latest error set, otherwise return 0.
93 */
filemap_check_wb_err(struct address_space * mapping,errseq_t since)94 static inline int filemap_check_wb_err(struct address_space *mapping,
95 errseq_t since)
96 {
97 return errseq_check(&mapping->wb_err, since);
98 }
99
100 /**
101 * filemap_sample_wb_err - sample the current errseq_t to test for later errors
102 * @mapping: mapping to be sampled
103 *
104 * Writeback errors are always reported relative to a particular sample point
105 * in the past. This function provides those sample points.
106 */
filemap_sample_wb_err(struct address_space * mapping)107 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
108 {
109 return errseq_sample(&mapping->wb_err);
110 }
111
112 /**
113 * file_sample_sb_err - sample the current errseq_t to test for later errors
114 * @file: file pointer to be sampled
115 *
116 * Grab the most current superblock-level errseq_t value for the given
117 * struct file.
118 */
file_sample_sb_err(struct file * file)119 static inline errseq_t file_sample_sb_err(struct file *file)
120 {
121 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err);
122 }
123
124 /*
125 * Flush file data before changing attributes. Caller must hold any locks
126 * required to prevent further writes to this file until we're done setting
127 * flags.
128 */
inode_drain_writes(struct inode * inode)129 static inline int inode_drain_writes(struct inode *inode)
130 {
131 inode_dio_wait(inode);
132 return filemap_write_and_wait(inode->i_mapping);
133 }
134
mapping_empty(struct address_space * mapping)135 static inline bool mapping_empty(struct address_space *mapping)
136 {
137 return xa_empty(&mapping->i_pages);
138 }
139
140 /*
141 * mapping_shrinkable - test if page cache state allows inode reclaim
142 * @mapping: the page cache mapping
143 *
144 * This checks the mapping's cache state for the pupose of inode
145 * reclaim and LRU management.
146 *
147 * The caller is expected to hold the i_lock, but is not required to
148 * hold the i_pages lock, which usually protects cache state. That's
149 * because the i_lock and the list_lru lock that protect the inode and
150 * its LRU state don't nest inside the irq-safe i_pages lock.
151 *
152 * Cache deletions are performed under the i_lock, which ensures that
153 * when an inode goes empty, it will reliably get queued on the LRU.
154 *
155 * Cache additions do not acquire the i_lock and may race with this
156 * check, in which case we'll report the inode as shrinkable when it
157 * has cache pages. This is okay: the shrinker also checks the
158 * refcount and the referenced bit, which will be elevated or set in
159 * the process of adding new cache pages to an inode.
160 */
mapping_shrinkable(struct address_space * mapping)161 static inline bool mapping_shrinkable(struct address_space *mapping)
162 {
163 void *head;
164
165 /*
166 * On highmem systems, there could be lowmem pressure from the
167 * inodes before there is highmem pressure from the page
168 * cache. Make inodes shrinkable regardless of cache state.
169 */
170 if (IS_ENABLED(CONFIG_HIGHMEM))
171 return true;
172
173 /* Cache completely empty? Shrink away. */
174 head = rcu_access_pointer(mapping->i_pages.xa_head);
175 if (!head)
176 return true;
177
178 /*
179 * The xarray stores single offset-0 entries directly in the
180 * head pointer, which allows non-resident page cache entries
181 * to escape the shadow shrinker's list of xarray nodes. The
182 * inode shrinker needs to pick them up under memory pressure.
183 */
184 if (!xa_is_node(head) && xa_is_value(head))
185 return true;
186
187 return false;
188 }
189
190 /*
191 * Bits in mapping->flags.
192 */
193 enum mapping_flags {
194 AS_EIO = 0, /* IO error on async write */
195 AS_ENOSPC = 1, /* ENOSPC on async write */
196 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
197 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
198 AS_EXITING = 4, /* final truncate in progress */
199 /* writeback related tags are not used */
200 AS_NO_WRITEBACK_TAGS = 5,
201 AS_LARGE_FOLIO_SUPPORT = 6,
202 };
203
204 /**
205 * mapping_set_error - record a writeback error in the address_space
206 * @mapping: the mapping in which an error should be set
207 * @error: the error to set in the mapping
208 *
209 * When writeback fails in some way, we must record that error so that
210 * userspace can be informed when fsync and the like are called. We endeavor
211 * to report errors on any file that was open at the time of the error. Some
212 * internal callers also need to know when writeback errors have occurred.
213 *
214 * When a writeback error occurs, most filesystems will want to call
215 * mapping_set_error to record the error in the mapping so that it can be
216 * reported when the application calls fsync(2).
217 */
mapping_set_error(struct address_space * mapping,int error)218 static inline void mapping_set_error(struct address_space *mapping, int error)
219 {
220 if (likely(!error))
221 return;
222
223 /* Record in wb_err for checkers using errseq_t based tracking */
224 __filemap_set_wb_err(mapping, error);
225
226 /* Record it in superblock */
227 if (mapping->host)
228 errseq_set(&mapping->host->i_sb->s_wb_err, error);
229
230 /* Record it in flags for now, for legacy callers */
231 if (error == -ENOSPC)
232 set_bit(AS_ENOSPC, &mapping->flags);
233 else
234 set_bit(AS_EIO, &mapping->flags);
235 }
236
mapping_set_unevictable(struct address_space * mapping)237 static inline void mapping_set_unevictable(struct address_space *mapping)
238 {
239 set_bit(AS_UNEVICTABLE, &mapping->flags);
240 }
241
mapping_clear_unevictable(struct address_space * mapping)242 static inline void mapping_clear_unevictable(struct address_space *mapping)
243 {
244 clear_bit(AS_UNEVICTABLE, &mapping->flags);
245 }
246
mapping_unevictable(struct address_space * mapping)247 static inline bool mapping_unevictable(struct address_space *mapping)
248 {
249 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
250 }
251
mapping_set_exiting(struct address_space * mapping)252 static inline void mapping_set_exiting(struct address_space *mapping)
253 {
254 set_bit(AS_EXITING, &mapping->flags);
255 }
256
mapping_exiting(struct address_space * mapping)257 static inline int mapping_exiting(struct address_space *mapping)
258 {
259 return test_bit(AS_EXITING, &mapping->flags);
260 }
261
mapping_set_no_writeback_tags(struct address_space * mapping)262 static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
263 {
264 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
265 }
266
mapping_use_writeback_tags(struct address_space * mapping)267 static inline int mapping_use_writeback_tags(struct address_space *mapping)
268 {
269 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
270 }
271
mapping_gfp_mask(struct address_space * mapping)272 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
273 {
274 return mapping->gfp_mask;
275 }
276
277 /* Restricts the given gfp_mask to what the mapping allows. */
mapping_gfp_constraint(struct address_space * mapping,gfp_t gfp_mask)278 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
279 gfp_t gfp_mask)
280 {
281 return mapping_gfp_mask(mapping) & gfp_mask;
282 }
283
284 /*
285 * This is non-atomic. Only to be used before the mapping is activated.
286 * Probably needs a barrier...
287 */
mapping_set_gfp_mask(struct address_space * m,gfp_t mask)288 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
289 {
290 m->gfp_mask = mask;
291 }
292
293 /**
294 * mapping_set_large_folios() - Indicate the file supports large folios.
295 * @mapping: The file.
296 *
297 * The filesystem should call this function in its inode constructor to
298 * indicate that the VFS can use large folios to cache the contents of
299 * the file.
300 *
301 * Context: This should not be called while the inode is active as it
302 * is non-atomic.
303 */
mapping_set_large_folios(struct address_space * mapping)304 static inline void mapping_set_large_folios(struct address_space *mapping)
305 {
306 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
307 }
308
309 /*
310 * Large folio support currently depends on THP. These dependencies are
311 * being worked on but are not yet fixed.
312 */
mapping_large_folio_support(struct address_space * mapping)313 static inline bool mapping_large_folio_support(struct address_space *mapping)
314 {
315 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
316 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
317 }
318
filemap_nr_thps(struct address_space * mapping)319 static inline int filemap_nr_thps(struct address_space *mapping)
320 {
321 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
322 return atomic_read(&mapping->nr_thps);
323 #else
324 return 0;
325 #endif
326 }
327
filemap_nr_thps_inc(struct address_space * mapping)328 static inline void filemap_nr_thps_inc(struct address_space *mapping)
329 {
330 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
331 if (!mapping_large_folio_support(mapping))
332 atomic_inc(&mapping->nr_thps);
333 #else
334 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
335 #endif
336 }
337
filemap_nr_thps_dec(struct address_space * mapping)338 static inline void filemap_nr_thps_dec(struct address_space *mapping)
339 {
340 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
341 if (!mapping_large_folio_support(mapping))
342 atomic_dec(&mapping->nr_thps);
343 #else
344 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
345 #endif
346 }
347
348 struct address_space *page_mapping(struct page *);
349 struct address_space *folio_mapping(struct folio *);
350 struct address_space *swapcache_mapping(struct folio *);
351
352 /**
353 * folio_file_mapping - Find the mapping this folio belongs to.
354 * @folio: The folio.
355 *
356 * For folios which are in the page cache, return the mapping that this
357 * page belongs to. Folios in the swap cache return the mapping of the
358 * swap file or swap device where the data is stored. This is different
359 * from the mapping returned by folio_mapping(). The only reason to
360 * use it is if, like NFS, you return 0 from ->activate_swapfile.
361 *
362 * Do not call this for folios which aren't in the page cache or swap cache.
363 */
folio_file_mapping(struct folio * folio)364 static inline struct address_space *folio_file_mapping(struct folio *folio)
365 {
366 if (unlikely(folio_test_swapcache(folio)))
367 return swapcache_mapping(folio);
368
369 return folio->mapping;
370 }
371
page_file_mapping(struct page * page)372 static inline struct address_space *page_file_mapping(struct page *page)
373 {
374 return folio_file_mapping(page_folio(page));
375 }
376
377 /*
378 * For file cache pages, return the address_space, otherwise return NULL
379 */
page_mapping_file(struct page * page)380 static inline struct address_space *page_mapping_file(struct page *page)
381 {
382 struct folio *folio = page_folio(page);
383
384 if (unlikely(folio_test_swapcache(folio)))
385 return NULL;
386 return folio_mapping(folio);
387 }
388
389 /**
390 * folio_inode - Get the host inode for this folio.
391 * @folio: The folio.
392 *
393 * For folios which are in the page cache, return the inode that this folio
394 * belongs to.
395 *
396 * Do not call this for folios which aren't in the page cache.
397 */
folio_inode(struct folio * folio)398 static inline struct inode *folio_inode(struct folio *folio)
399 {
400 return folio->mapping->host;
401 }
402
403 /**
404 * folio_attach_private - Attach private data to a folio.
405 * @folio: Folio to attach data to.
406 * @data: Data to attach to folio.
407 *
408 * Attaching private data to a folio increments the page's reference count.
409 * The data must be detached before the folio will be freed.
410 */
folio_attach_private(struct folio * folio,void * data)411 static inline void folio_attach_private(struct folio *folio, void *data)
412 {
413 folio_get(folio);
414 folio->private = data;
415 folio_set_private(folio);
416 }
417
418 /**
419 * folio_change_private - Change private data on a folio.
420 * @folio: Folio to change the data on.
421 * @data: Data to set on the folio.
422 *
423 * Change the private data attached to a folio and return the old
424 * data. The page must previously have had data attached and the data
425 * must be detached before the folio will be freed.
426 *
427 * Return: Data that was previously attached to the folio.
428 */
folio_change_private(struct folio * folio,void * data)429 static inline void *folio_change_private(struct folio *folio, void *data)
430 {
431 void *old = folio_get_private(folio);
432
433 folio->private = data;
434 return old;
435 }
436
437 /**
438 * folio_detach_private - Detach private data from a folio.
439 * @folio: Folio to detach data from.
440 *
441 * Removes the data that was previously attached to the folio and decrements
442 * the refcount on the page.
443 *
444 * Return: Data that was attached to the folio.
445 */
folio_detach_private(struct folio * folio)446 static inline void *folio_detach_private(struct folio *folio)
447 {
448 void *data = folio_get_private(folio);
449
450 if (!folio_test_private(folio))
451 return NULL;
452 folio_clear_private(folio);
453 folio->private = NULL;
454 folio_put(folio);
455
456 return data;
457 }
458
attach_page_private(struct page * page,void * data)459 static inline void attach_page_private(struct page *page, void *data)
460 {
461 folio_attach_private(page_folio(page), data);
462 }
463
detach_page_private(struct page * page)464 static inline void *detach_page_private(struct page *page)
465 {
466 return folio_detach_private(page_folio(page));
467 }
468
469 #ifdef CONFIG_NUMA
470 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
471 #else
filemap_alloc_folio(gfp_t gfp,unsigned int order)472 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
473 {
474 return folio_alloc(gfp, order);
475 }
476 #endif
477
__page_cache_alloc(gfp_t gfp)478 static inline struct page *__page_cache_alloc(gfp_t gfp)
479 {
480 return &filemap_alloc_folio(gfp, 0)->page;
481 }
482
page_cache_alloc(struct address_space * x)483 static inline struct page *page_cache_alloc(struct address_space *x)
484 {
485 return __page_cache_alloc(mapping_gfp_mask(x));
486 }
487
readahead_gfp_mask(struct address_space * x)488 static inline gfp_t readahead_gfp_mask(struct address_space *x)
489 {
490 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
491 }
492
493 typedef int filler_t(struct file *, struct folio *);
494
495 pgoff_t page_cache_next_miss(struct address_space *mapping,
496 pgoff_t index, unsigned long max_scan);
497 pgoff_t page_cache_prev_miss(struct address_space *mapping,
498 pgoff_t index, unsigned long max_scan);
499
500 #define FGP_ACCESSED 0x00000001
501 #define FGP_LOCK 0x00000002
502 #define FGP_CREAT 0x00000004
503 #define FGP_WRITE 0x00000008
504 #define FGP_NOFS 0x00000010
505 #define FGP_NOWAIT 0x00000020
506 #define FGP_FOR_MMAP 0x00000040
507 #define FGP_HEAD 0x00000080
508 #define FGP_ENTRY 0x00000100
509 #define FGP_STABLE 0x00000200
510
511 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
512 int fgp_flags, gfp_t gfp);
513 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
514 int fgp_flags, gfp_t gfp);
515
516 /**
517 * filemap_get_folio - Find and get a folio.
518 * @mapping: The address_space to search.
519 * @index: The page index.
520 *
521 * Looks up the page cache entry at @mapping & @index. If a folio is
522 * present, it is returned with an increased refcount.
523 *
524 * Otherwise, %NULL is returned.
525 */
filemap_get_folio(struct address_space * mapping,pgoff_t index)526 static inline struct folio *filemap_get_folio(struct address_space *mapping,
527 pgoff_t index)
528 {
529 return __filemap_get_folio(mapping, index, 0, 0);
530 }
531
532 /**
533 * filemap_lock_folio - Find and lock a folio.
534 * @mapping: The address_space to search.
535 * @index: The page index.
536 *
537 * Looks up the page cache entry at @mapping & @index. If a folio is
538 * present, it is returned locked with an increased refcount.
539 *
540 * Context: May sleep.
541 * Return: A folio or %NULL if there is no folio in the cache for this
542 * index. Will not return a shadow, swap or DAX entry.
543 */
filemap_lock_folio(struct address_space * mapping,pgoff_t index)544 static inline struct folio *filemap_lock_folio(struct address_space *mapping,
545 pgoff_t index)
546 {
547 return __filemap_get_folio(mapping, index, FGP_LOCK, 0);
548 }
549
550 /**
551 * find_get_page - find and get a page reference
552 * @mapping: the address_space to search
553 * @offset: the page index
554 *
555 * Looks up the page cache slot at @mapping & @offset. If there is a
556 * page cache page, it is returned with an increased refcount.
557 *
558 * Otherwise, %NULL is returned.
559 */
find_get_page(struct address_space * mapping,pgoff_t offset)560 static inline struct page *find_get_page(struct address_space *mapping,
561 pgoff_t offset)
562 {
563 return pagecache_get_page(mapping, offset, 0, 0);
564 }
565
find_get_page_flags(struct address_space * mapping,pgoff_t offset,int fgp_flags)566 static inline struct page *find_get_page_flags(struct address_space *mapping,
567 pgoff_t offset, int fgp_flags)
568 {
569 return pagecache_get_page(mapping, offset, fgp_flags, 0);
570 }
571
572 /**
573 * find_lock_page - locate, pin and lock a pagecache page
574 * @mapping: the address_space to search
575 * @index: the page index
576 *
577 * Looks up the page cache entry at @mapping & @index. If there is a
578 * page cache page, it is returned locked and with an increased
579 * refcount.
580 *
581 * Context: May sleep.
582 * Return: A struct page or %NULL if there is no page in the cache for this
583 * index.
584 */
find_lock_page(struct address_space * mapping,pgoff_t index)585 static inline struct page *find_lock_page(struct address_space *mapping,
586 pgoff_t index)
587 {
588 return pagecache_get_page(mapping, index, FGP_LOCK, 0);
589 }
590
591 /**
592 * find_or_create_page - locate or add a pagecache page
593 * @mapping: the page's address_space
594 * @index: the page's index into the mapping
595 * @gfp_mask: page allocation mode
596 *
597 * Looks up the page cache slot at @mapping & @offset. If there is a
598 * page cache page, it is returned locked and with an increased
599 * refcount.
600 *
601 * If the page is not present, a new page is allocated using @gfp_mask
602 * and added to the page cache and the VM's LRU list. The page is
603 * returned locked and with an increased refcount.
604 *
605 * On memory exhaustion, %NULL is returned.
606 *
607 * find_or_create_page() may sleep, even if @gfp_flags specifies an
608 * atomic allocation!
609 */
find_or_create_page(struct address_space * mapping,pgoff_t index,gfp_t gfp_mask)610 static inline struct page *find_or_create_page(struct address_space *mapping,
611 pgoff_t index, gfp_t gfp_mask)
612 {
613 return pagecache_get_page(mapping, index,
614 FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
615 gfp_mask);
616 }
617
618 /**
619 * grab_cache_page_nowait - returns locked page at given index in given cache
620 * @mapping: target address_space
621 * @index: the page index
622 *
623 * Same as grab_cache_page(), but do not wait if the page is unavailable.
624 * This is intended for speculative data generators, where the data can
625 * be regenerated if the page couldn't be grabbed. This routine should
626 * be safe to call while holding the lock for another page.
627 *
628 * Clear __GFP_FS when allocating the page to avoid recursion into the fs
629 * and deadlock against the caller's locked page.
630 */
grab_cache_page_nowait(struct address_space * mapping,pgoff_t index)631 static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
632 pgoff_t index)
633 {
634 return pagecache_get_page(mapping, index,
635 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
636 mapping_gfp_mask(mapping));
637 }
638
639 #define swapcache_index(folio) __page_file_index(&(folio)->page)
640
641 /**
642 * folio_index - File index of a folio.
643 * @folio: The folio.
644 *
645 * For a folio which is either in the page cache or the swap cache,
646 * return its index within the address_space it belongs to. If you know
647 * the page is definitely in the page cache, you can look at the folio's
648 * index directly.
649 *
650 * Return: The index (offset in units of pages) of a folio in its file.
651 */
folio_index(struct folio * folio)652 static inline pgoff_t folio_index(struct folio *folio)
653 {
654 if (unlikely(folio_test_swapcache(folio)))
655 return swapcache_index(folio);
656 return folio->index;
657 }
658
659 /**
660 * folio_next_index - Get the index of the next folio.
661 * @folio: The current folio.
662 *
663 * Return: The index of the folio which follows this folio in the file.
664 */
folio_next_index(struct folio * folio)665 static inline pgoff_t folio_next_index(struct folio *folio)
666 {
667 return folio->index + folio_nr_pages(folio);
668 }
669
670 /**
671 * folio_file_page - The page for a particular index.
672 * @folio: The folio which contains this index.
673 * @index: The index we want to look up.
674 *
675 * Sometimes after looking up a folio in the page cache, we need to
676 * obtain the specific page for an index (eg a page fault).
677 *
678 * Return: The page containing the file data for this index.
679 */
folio_file_page(struct folio * folio,pgoff_t index)680 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
681 {
682 /* HugeTLBfs indexes the page cache in units of hpage_size */
683 if (folio_test_hugetlb(folio))
684 return &folio->page;
685 return folio_page(folio, index & (folio_nr_pages(folio) - 1));
686 }
687
688 /**
689 * folio_contains - Does this folio contain this index?
690 * @folio: The folio.
691 * @index: The page index within the file.
692 *
693 * Context: The caller should have the page locked in order to prevent
694 * (eg) shmem from moving the page between the page cache and swap cache
695 * and changing its index in the middle of the operation.
696 * Return: true or false.
697 */
folio_contains(struct folio * folio,pgoff_t index)698 static inline bool folio_contains(struct folio *folio, pgoff_t index)
699 {
700 /* HugeTLBfs indexes the page cache in units of hpage_size */
701 if (folio_test_hugetlb(folio))
702 return folio->index == index;
703 return index - folio_index(folio) < folio_nr_pages(folio);
704 }
705
706 /*
707 * Given the page we found in the page cache, return the page corresponding
708 * to this index in the file
709 */
find_subpage(struct page * head,pgoff_t index)710 static inline struct page *find_subpage(struct page *head, pgoff_t index)
711 {
712 /* HugeTLBfs wants the head page regardless */
713 if (PageHuge(head))
714 return head;
715
716 return head + (index & (thp_nr_pages(head) - 1));
717 }
718
719 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
720 pgoff_t end, struct folio_batch *fbatch);
721 unsigned filemap_get_folios_contig(struct address_space *mapping,
722 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
723 unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
724 pgoff_t end, xa_mark_t tag, unsigned int nr_pages,
725 struct page **pages);
find_get_pages_tag(struct address_space * mapping,pgoff_t * index,xa_mark_t tag,unsigned int nr_pages,struct page ** pages)726 static inline unsigned find_get_pages_tag(struct address_space *mapping,
727 pgoff_t *index, xa_mark_t tag, unsigned int nr_pages,
728 struct page **pages)
729 {
730 return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
731 nr_pages, pages);
732 }
733
734 struct page *grab_cache_page_write_begin(struct address_space *mapping,
735 pgoff_t index);
736
737 /*
738 * Returns locked page at given index in given cache, creating it if needed.
739 */
grab_cache_page(struct address_space * mapping,pgoff_t index)740 static inline struct page *grab_cache_page(struct address_space *mapping,
741 pgoff_t index)
742 {
743 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
744 }
745
746 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
747 filler_t *filler, struct file *file);
748 struct page *read_cache_page(struct address_space *, pgoff_t index,
749 filler_t *filler, struct file *file);
750 extern struct page * read_cache_page_gfp(struct address_space *mapping,
751 pgoff_t index, gfp_t gfp_mask);
752
read_mapping_page(struct address_space * mapping,pgoff_t index,struct file * file)753 static inline struct page *read_mapping_page(struct address_space *mapping,
754 pgoff_t index, struct file *file)
755 {
756 return read_cache_page(mapping, index, NULL, file);
757 }
758
read_mapping_folio(struct address_space * mapping,pgoff_t index,struct file * file)759 static inline struct folio *read_mapping_folio(struct address_space *mapping,
760 pgoff_t index, struct file *file)
761 {
762 return read_cache_folio(mapping, index, NULL, file);
763 }
764
765 /*
766 * Get index of the page within radix-tree (but not for hugetlb pages).
767 * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
768 */
page_to_index(struct page * page)769 static inline pgoff_t page_to_index(struct page *page)
770 {
771 struct page *head;
772
773 if (likely(!PageTransTail(page)))
774 return page->index;
775
776 head = compound_head(page);
777 /*
778 * We don't initialize ->index for tail pages: calculate based on
779 * head page
780 */
781 return head->index + page - head;
782 }
783
784 extern pgoff_t hugetlb_basepage_index(struct page *page);
785
786 /*
787 * Get the offset in PAGE_SIZE (even for hugetlb pages).
788 * (TODO: hugetlb pages should have ->index in PAGE_SIZE)
789 */
page_to_pgoff(struct page * page)790 static inline pgoff_t page_to_pgoff(struct page *page)
791 {
792 if (unlikely(PageHuge(page)))
793 return hugetlb_basepage_index(page);
794 return page_to_index(page);
795 }
796
797 /*
798 * Return byte-offset into filesystem object for page.
799 */
page_offset(struct page * page)800 static inline loff_t page_offset(struct page *page)
801 {
802 return ((loff_t)page->index) << PAGE_SHIFT;
803 }
804
page_file_offset(struct page * page)805 static inline loff_t page_file_offset(struct page *page)
806 {
807 return ((loff_t)page_index(page)) << PAGE_SHIFT;
808 }
809
810 /**
811 * folio_pos - Returns the byte position of this folio in its file.
812 * @folio: The folio.
813 */
folio_pos(struct folio * folio)814 static inline loff_t folio_pos(struct folio *folio)
815 {
816 return page_offset(&folio->page);
817 }
818
819 /**
820 * folio_file_pos - Returns the byte position of this folio in its file.
821 * @folio: The folio.
822 *
823 * This differs from folio_pos() for folios which belong to a swap file.
824 * NFS is the only filesystem today which needs to use folio_file_pos().
825 */
folio_file_pos(struct folio * folio)826 static inline loff_t folio_file_pos(struct folio *folio)
827 {
828 return page_file_offset(&folio->page);
829 }
830
831 /*
832 * Get the offset in PAGE_SIZE (even for hugetlb folios).
833 * (TODO: hugetlb folios should have ->index in PAGE_SIZE)
834 */
folio_pgoff(struct folio * folio)835 static inline pgoff_t folio_pgoff(struct folio *folio)
836 {
837 if (unlikely(folio_test_hugetlb(folio)))
838 return hugetlb_basepage_index(&folio->page);
839 return folio->index;
840 }
841
842 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
843 unsigned long address);
844
linear_page_index(struct vm_area_struct * vma,unsigned long address)845 static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
846 unsigned long address)
847 {
848 pgoff_t pgoff;
849 if (unlikely(is_vm_hugetlb_page(vma)))
850 return linear_hugepage_index(vma, address);
851 pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
852 pgoff += vma->vm_pgoff;
853 return pgoff;
854 }
855
856 struct wait_page_key {
857 struct folio *folio;
858 int bit_nr;
859 int page_match;
860 };
861
862 struct wait_page_queue {
863 struct folio *folio;
864 int bit_nr;
865 wait_queue_entry_t wait;
866 };
867
wake_page_match(struct wait_page_queue * wait_page,struct wait_page_key * key)868 static inline bool wake_page_match(struct wait_page_queue *wait_page,
869 struct wait_page_key *key)
870 {
871 if (wait_page->folio != key->folio)
872 return false;
873 key->page_match = 1;
874
875 if (wait_page->bit_nr != key->bit_nr)
876 return false;
877
878 return true;
879 }
880
881 void __folio_lock(struct folio *folio);
882 int __folio_lock_killable(struct folio *folio);
883 bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
884 unsigned int flags);
885 void unlock_page(struct page *page);
886 void folio_unlock(struct folio *folio);
887
888 /**
889 * folio_trylock() - Attempt to lock a folio.
890 * @folio: The folio to attempt to lock.
891 *
892 * Sometimes it is undesirable to wait for a folio to be unlocked (eg
893 * when the locks are being taken in the wrong order, or if making
894 * progress through a batch of folios is more important than processing
895 * them in order). Usually folio_lock() is the correct function to call.
896 *
897 * Context: Any context.
898 * Return: Whether the lock was successfully acquired.
899 */
folio_trylock(struct folio * folio)900 static inline bool folio_trylock(struct folio *folio)
901 {
902 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
903 }
904
905 /*
906 * Return true if the page was successfully locked
907 */
trylock_page(struct page * page)908 static inline int trylock_page(struct page *page)
909 {
910 return folio_trylock(page_folio(page));
911 }
912
913 /**
914 * folio_lock() - Lock this folio.
915 * @folio: The folio to lock.
916 *
917 * The folio lock protects against many things, probably more than it
918 * should. It is primarily held while a folio is being brought uptodate,
919 * either from its backing file or from swap. It is also held while a
920 * folio is being truncated from its address_space, so holding the lock
921 * is sufficient to keep folio->mapping stable.
922 *
923 * The folio lock is also held while write() is modifying the page to
924 * provide POSIX atomicity guarantees (as long as the write does not
925 * cross a page boundary). Other modifications to the data in the folio
926 * do not hold the folio lock and can race with writes, eg DMA and stores
927 * to mapped pages.
928 *
929 * Context: May sleep. If you need to acquire the locks of two or
930 * more folios, they must be in order of ascending index, if they are
931 * in the same address_space. If they are in different address_spaces,
932 * acquire the lock of the folio which belongs to the address_space which
933 * has the lowest address in memory first.
934 */
folio_lock(struct folio * folio)935 static inline void folio_lock(struct folio *folio)
936 {
937 might_sleep();
938 if (!folio_trylock(folio))
939 __folio_lock(folio);
940 }
941
942 /**
943 * lock_page() - Lock the folio containing this page.
944 * @page: The page to lock.
945 *
946 * See folio_lock() for a description of what the lock protects.
947 * This is a legacy function and new code should probably use folio_lock()
948 * instead.
949 *
950 * Context: May sleep. Pages in the same folio share a lock, so do not
951 * attempt to lock two pages which share a folio.
952 */
lock_page(struct page * page)953 static inline void lock_page(struct page *page)
954 {
955 struct folio *folio;
956 might_sleep();
957
958 folio = page_folio(page);
959 if (!folio_trylock(folio))
960 __folio_lock(folio);
961 }
962
963 /**
964 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
965 * @folio: The folio to lock.
966 *
967 * Attempts to lock the folio, like folio_lock(), except that the sleep
968 * to acquire the lock is interruptible by a fatal signal.
969 *
970 * Context: May sleep; see folio_lock().
971 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
972 */
folio_lock_killable(struct folio * folio)973 static inline int folio_lock_killable(struct folio *folio)
974 {
975 might_sleep();
976 if (!folio_trylock(folio))
977 return __folio_lock_killable(folio);
978 return 0;
979 }
980
981 /*
982 * lock_page_killable is like lock_page but can be interrupted by fatal
983 * signals. It returns 0 if it locked the page and -EINTR if it was
984 * killed while waiting.
985 */
lock_page_killable(struct page * page)986 static inline int lock_page_killable(struct page *page)
987 {
988 return folio_lock_killable(page_folio(page));
989 }
990
991 /*
992 * folio_lock_or_retry - Lock the folio, unless this would block and the
993 * caller indicated that it can handle a retry.
994 *
995 * Return value and mmap_lock implications depend on flags; see
996 * __folio_lock_or_retry().
997 */
folio_lock_or_retry(struct folio * folio,struct mm_struct * mm,unsigned int flags)998 static inline bool folio_lock_or_retry(struct folio *folio,
999 struct mm_struct *mm, unsigned int flags)
1000 {
1001 might_sleep();
1002 return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags);
1003 }
1004
1005 /*
1006 * This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
1007 * and should not be used directly.
1008 */
1009 void folio_wait_bit(struct folio *folio, int bit_nr);
1010 int folio_wait_bit_killable(struct folio *folio, int bit_nr);
1011
1012 /*
1013 * Wait for a folio to be unlocked.
1014 *
1015 * This must be called with the caller "holding" the folio,
1016 * ie with increased folio reference count so that the folio won't
1017 * go away during the wait.
1018 */
folio_wait_locked(struct folio * folio)1019 static inline void folio_wait_locked(struct folio *folio)
1020 {
1021 if (folio_test_locked(folio))
1022 folio_wait_bit(folio, PG_locked);
1023 }
1024
folio_wait_locked_killable(struct folio * folio)1025 static inline int folio_wait_locked_killable(struct folio *folio)
1026 {
1027 if (!folio_test_locked(folio))
1028 return 0;
1029 return folio_wait_bit_killable(folio, PG_locked);
1030 }
1031
wait_on_page_locked(struct page * page)1032 static inline void wait_on_page_locked(struct page *page)
1033 {
1034 folio_wait_locked(page_folio(page));
1035 }
1036
wait_on_page_locked_killable(struct page * page)1037 static inline int wait_on_page_locked_killable(struct page *page)
1038 {
1039 return folio_wait_locked_killable(page_folio(page));
1040 }
1041
1042 void wait_on_page_writeback(struct page *page);
1043 void folio_wait_writeback(struct folio *folio);
1044 int folio_wait_writeback_killable(struct folio *folio);
1045 void end_page_writeback(struct page *page);
1046 void folio_end_writeback(struct folio *folio);
1047 void wait_for_stable_page(struct page *page);
1048 void folio_wait_stable(struct folio *folio);
1049 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
__set_page_dirty(struct page * page,struct address_space * mapping,int warn)1050 static inline void __set_page_dirty(struct page *page,
1051 struct address_space *mapping, int warn)
1052 {
1053 __folio_mark_dirty(page_folio(page), mapping, warn);
1054 }
1055 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
1056 void __folio_cancel_dirty(struct folio *folio);
folio_cancel_dirty(struct folio * folio)1057 static inline void folio_cancel_dirty(struct folio *folio)
1058 {
1059 /* Avoid atomic ops, locking, etc. when not actually needed. */
1060 if (folio_test_dirty(folio))
1061 __folio_cancel_dirty(folio);
1062 }
1063 bool folio_clear_dirty_for_io(struct folio *folio);
1064 bool clear_page_dirty_for_io(struct page *page);
1065 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
1066 int __must_check folio_write_one(struct folio *folio);
write_one_page(struct page * page)1067 static inline int __must_check write_one_page(struct page *page)
1068 {
1069 return folio_write_one(page_folio(page));
1070 }
1071
1072 int __set_page_dirty_nobuffers(struct page *page);
1073 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
1074
1075 #ifdef CONFIG_MIGRATION
1076 int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
1077 struct folio *src, enum migrate_mode mode);
1078 #else
1079 #define filemap_migrate_folio NULL
1080 #endif
1081 void page_endio(struct page *page, bool is_write, int err);
1082
1083 void folio_end_private_2(struct folio *folio);
1084 void folio_wait_private_2(struct folio *folio);
1085 int folio_wait_private_2_killable(struct folio *folio);
1086
1087 /*
1088 * Add an arbitrary waiter to a page's wait queue
1089 */
1090 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
1091
1092 /*
1093 * Fault in userspace address range.
1094 */
1095 size_t fault_in_writeable(char __user *uaddr, size_t size);
1096 size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
1097 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
1098 size_t fault_in_readable(const char __user *uaddr, size_t size);
1099
1100 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
1101 pgoff_t index, gfp_t gfp);
1102 int filemap_add_folio(struct address_space *mapping, struct folio *folio,
1103 pgoff_t index, gfp_t gfp);
1104 void filemap_remove_folio(struct folio *folio);
1105 void delete_from_page_cache(struct page *page);
1106 void __filemap_remove_folio(struct folio *folio, void *shadow);
1107 void replace_page_cache_page(struct page *old, struct page *new);
1108 void delete_from_page_cache_batch(struct address_space *mapping,
1109 struct folio_batch *fbatch);
1110 int try_to_release_page(struct page *page, gfp_t gfp);
1111 bool filemap_release_folio(struct folio *folio, gfp_t gfp);
1112 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
1113 int whence);
1114
1115 /* Must be non-static for BPF error injection */
1116 int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
1117 pgoff_t index, gfp_t gfp, void **shadowp);
1118
1119 bool filemap_range_has_writeback(struct address_space *mapping,
1120 loff_t start_byte, loff_t end_byte);
1121
1122 /**
1123 * filemap_range_needs_writeback - check if range potentially needs writeback
1124 * @mapping: address space within which to check
1125 * @start_byte: offset in bytes where the range starts
1126 * @end_byte: offset in bytes where the range ends (inclusive)
1127 *
1128 * Find at least one page in the range supplied, usually used to check if
1129 * direct writing in this range will trigger a writeback. Used by O_DIRECT
1130 * read/write with IOCB_NOWAIT, to see if the caller needs to do
1131 * filemap_write_and_wait_range() before proceeding.
1132 *
1133 * Return: %true if the caller should do filemap_write_and_wait_range() before
1134 * doing O_DIRECT to a page in this range, %false otherwise.
1135 */
filemap_range_needs_writeback(struct address_space * mapping,loff_t start_byte,loff_t end_byte)1136 static inline bool filemap_range_needs_writeback(struct address_space *mapping,
1137 loff_t start_byte,
1138 loff_t end_byte)
1139 {
1140 if (!mapping->nrpages)
1141 return false;
1142 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
1143 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
1144 return false;
1145 return filemap_range_has_writeback(mapping, start_byte, end_byte);
1146 }
1147
1148 /**
1149 * struct readahead_control - Describes a readahead request.
1150 *
1151 * A readahead request is for consecutive pages. Filesystems which
1152 * implement the ->readahead method should call readahead_page() or
1153 * readahead_page_batch() in a loop and attempt to start I/O against
1154 * each page in the request.
1155 *
1156 * Most of the fields in this struct are private and should be accessed
1157 * by the functions below.
1158 *
1159 * @file: The file, used primarily by network filesystems for authentication.
1160 * May be NULL if invoked internally by the filesystem.
1161 * @mapping: Readahead this filesystem object.
1162 * @ra: File readahead state. May be NULL.
1163 */
1164 struct readahead_control {
1165 struct file *file;
1166 struct address_space *mapping;
1167 struct file_ra_state *ra;
1168 /* private: use the readahead_* accessors instead */
1169 pgoff_t _index;
1170 unsigned int _nr_pages;
1171 unsigned int _batch_count;
1172 bool _workingset;
1173 unsigned long _pflags;
1174 };
1175
1176 #define DEFINE_READAHEAD(ractl, f, r, m, i) \
1177 struct readahead_control ractl = { \
1178 .file = f, \
1179 .mapping = m, \
1180 .ra = r, \
1181 ._index = i, \
1182 }
1183
1184 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
1185
1186 void page_cache_ra_unbounded(struct readahead_control *,
1187 unsigned long nr_to_read, unsigned long lookahead_count);
1188 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
1189 void page_cache_async_ra(struct readahead_control *, struct folio *,
1190 unsigned long req_count);
1191 void readahead_expand(struct readahead_control *ractl,
1192 loff_t new_start, size_t new_len);
1193
1194 /**
1195 * page_cache_sync_readahead - generic file readahead
1196 * @mapping: address_space which holds the pagecache and I/O vectors
1197 * @ra: file_ra_state which holds the readahead state
1198 * @file: Used by the filesystem for authentication.
1199 * @index: Index of first page to be read.
1200 * @req_count: Total number of pages being read by the caller.
1201 *
1202 * page_cache_sync_readahead() should be called when a cache miss happened:
1203 * it will submit the read. The readahead logic may decide to piggyback more
1204 * pages onto the read request if access patterns suggest it will improve
1205 * performance.
1206 */
1207 static inline
page_cache_sync_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,pgoff_t index,unsigned long req_count)1208 void page_cache_sync_readahead(struct address_space *mapping,
1209 struct file_ra_state *ra, struct file *file, pgoff_t index,
1210 unsigned long req_count)
1211 {
1212 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1213 page_cache_sync_ra(&ractl, req_count);
1214 }
1215
1216 /**
1217 * page_cache_async_readahead - file readahead for marked pages
1218 * @mapping: address_space which holds the pagecache and I/O vectors
1219 * @ra: file_ra_state which holds the readahead state
1220 * @file: Used by the filesystem for authentication.
1221 * @folio: The folio at @index which triggered the readahead call.
1222 * @index: Index of first page to be read.
1223 * @req_count: Total number of pages being read by the caller.
1224 *
1225 * page_cache_async_readahead() should be called when a page is used which
1226 * is marked as PageReadahead; this is a marker to suggest that the application
1227 * has used up enough of the readahead window that we should start pulling in
1228 * more pages.
1229 */
1230 static inline
page_cache_async_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,struct folio * folio,pgoff_t index,unsigned long req_count)1231 void page_cache_async_readahead(struct address_space *mapping,
1232 struct file_ra_state *ra, struct file *file,
1233 struct folio *folio, pgoff_t index, unsigned long req_count)
1234 {
1235 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1236 page_cache_async_ra(&ractl, folio, req_count);
1237 }
1238
__readahead_folio(struct readahead_control * ractl)1239 static inline struct folio *__readahead_folio(struct readahead_control *ractl)
1240 {
1241 struct folio *folio;
1242
1243 BUG_ON(ractl->_batch_count > ractl->_nr_pages);
1244 ractl->_nr_pages -= ractl->_batch_count;
1245 ractl->_index += ractl->_batch_count;
1246
1247 if (!ractl->_nr_pages) {
1248 ractl->_batch_count = 0;
1249 return NULL;
1250 }
1251
1252 folio = xa_load(&ractl->mapping->i_pages, ractl->_index);
1253 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
1254 ractl->_batch_count = folio_nr_pages(folio);
1255
1256 return folio;
1257 }
1258
1259 /**
1260 * readahead_page - Get the next page to read.
1261 * @ractl: The current readahead request.
1262 *
1263 * Context: The page is locked and has an elevated refcount. The caller
1264 * should decreases the refcount once the page has been submitted for I/O
1265 * and unlock the page once all I/O to that page has completed.
1266 * Return: A pointer to the next page, or %NULL if we are done.
1267 */
readahead_page(struct readahead_control * ractl)1268 static inline struct page *readahead_page(struct readahead_control *ractl)
1269 {
1270 struct folio *folio = __readahead_folio(ractl);
1271
1272 return &folio->page;
1273 }
1274
1275 /**
1276 * readahead_folio - Get the next folio to read.
1277 * @ractl: The current readahead request.
1278 *
1279 * Context: The folio is locked. The caller should unlock the folio once
1280 * all I/O to that folio has completed.
1281 * Return: A pointer to the next folio, or %NULL if we are done.
1282 */
readahead_folio(struct readahead_control * ractl)1283 static inline struct folio *readahead_folio(struct readahead_control *ractl)
1284 {
1285 struct folio *folio = __readahead_folio(ractl);
1286
1287 if (folio)
1288 folio_put(folio);
1289 return folio;
1290 }
1291
__readahead_batch(struct readahead_control * rac,struct page ** array,unsigned int array_sz)1292 static inline unsigned int __readahead_batch(struct readahead_control *rac,
1293 struct page **array, unsigned int array_sz)
1294 {
1295 unsigned int i = 0;
1296 XA_STATE(xas, &rac->mapping->i_pages, 0);
1297 struct page *page;
1298
1299 BUG_ON(rac->_batch_count > rac->_nr_pages);
1300 rac->_nr_pages -= rac->_batch_count;
1301 rac->_index += rac->_batch_count;
1302 rac->_batch_count = 0;
1303
1304 xas_set(&xas, rac->_index);
1305 rcu_read_lock();
1306 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
1307 if (xas_retry(&xas, page))
1308 continue;
1309 VM_BUG_ON_PAGE(!PageLocked(page), page);
1310 VM_BUG_ON_PAGE(PageTail(page), page);
1311 array[i++] = page;
1312 rac->_batch_count += thp_nr_pages(page);
1313 if (i == array_sz)
1314 break;
1315 }
1316 rcu_read_unlock();
1317
1318 return i;
1319 }
1320
1321 /**
1322 * readahead_page_batch - Get a batch of pages to read.
1323 * @rac: The current readahead request.
1324 * @array: An array of pointers to struct page.
1325 *
1326 * Context: The pages are locked and have an elevated refcount. The caller
1327 * should decreases the refcount once the page has been submitted for I/O
1328 * and unlock the page once all I/O to that page has completed.
1329 * Return: The number of pages placed in the array. 0 indicates the request
1330 * is complete.
1331 */
1332 #define readahead_page_batch(rac, array) \
1333 __readahead_batch(rac, array, ARRAY_SIZE(array))
1334
1335 /**
1336 * readahead_pos - The byte offset into the file of this readahead request.
1337 * @rac: The readahead request.
1338 */
readahead_pos(struct readahead_control * rac)1339 static inline loff_t readahead_pos(struct readahead_control *rac)
1340 {
1341 return (loff_t)rac->_index * PAGE_SIZE;
1342 }
1343
1344 /**
1345 * readahead_length - The number of bytes in this readahead request.
1346 * @rac: The readahead request.
1347 */
readahead_length(struct readahead_control * rac)1348 static inline size_t readahead_length(struct readahead_control *rac)
1349 {
1350 return rac->_nr_pages * PAGE_SIZE;
1351 }
1352
1353 /**
1354 * readahead_index - The index of the first page in this readahead request.
1355 * @rac: The readahead request.
1356 */
readahead_index(struct readahead_control * rac)1357 static inline pgoff_t readahead_index(struct readahead_control *rac)
1358 {
1359 return rac->_index;
1360 }
1361
1362 /**
1363 * readahead_count - The number of pages in this readahead request.
1364 * @rac: The readahead request.
1365 */
readahead_count(struct readahead_control * rac)1366 static inline unsigned int readahead_count(struct readahead_control *rac)
1367 {
1368 return rac->_nr_pages;
1369 }
1370
1371 /**
1372 * readahead_batch_length - The number of bytes in the current batch.
1373 * @rac: The readahead request.
1374 */
readahead_batch_length(struct readahead_control * rac)1375 static inline size_t readahead_batch_length(struct readahead_control *rac)
1376 {
1377 return rac->_batch_count * PAGE_SIZE;
1378 }
1379
dir_pages(struct inode * inode)1380 static inline unsigned long dir_pages(struct inode *inode)
1381 {
1382 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
1383 PAGE_SHIFT;
1384 }
1385
1386 /**
1387 * folio_mkwrite_check_truncate - check if folio was truncated
1388 * @folio: the folio to check
1389 * @inode: the inode to check the folio against
1390 *
1391 * Return: the number of bytes in the folio up to EOF,
1392 * or -EFAULT if the folio was truncated.
1393 */
folio_mkwrite_check_truncate(struct folio * folio,struct inode * inode)1394 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
1395 struct inode *inode)
1396 {
1397 loff_t size = i_size_read(inode);
1398 pgoff_t index = size >> PAGE_SHIFT;
1399 size_t offset = offset_in_folio(folio, size);
1400
1401 if (!folio->mapping)
1402 return -EFAULT;
1403
1404 /* folio is wholly inside EOF */
1405 if (folio_next_index(folio) - 1 < index)
1406 return folio_size(folio);
1407 /* folio is wholly past EOF */
1408 if (folio->index > index || !offset)
1409 return -EFAULT;
1410 /* folio is partially inside EOF */
1411 return offset;
1412 }
1413
1414 /**
1415 * page_mkwrite_check_truncate - check if page was truncated
1416 * @page: the page to check
1417 * @inode: the inode to check the page against
1418 *
1419 * Returns the number of bytes in the page up to EOF,
1420 * or -EFAULT if the page was truncated.
1421 */
page_mkwrite_check_truncate(struct page * page,struct inode * inode)1422 static inline int page_mkwrite_check_truncate(struct page *page,
1423 struct inode *inode)
1424 {
1425 loff_t size = i_size_read(inode);
1426 pgoff_t index = size >> PAGE_SHIFT;
1427 int offset = offset_in_page(size);
1428
1429 if (page->mapping != inode->i_mapping)
1430 return -EFAULT;
1431
1432 /* page is wholly inside EOF */
1433 if (page->index < index)
1434 return PAGE_SIZE;
1435 /* page is wholly past EOF */
1436 if (page->index > index || !offset)
1437 return -EFAULT;
1438 /* page is partially inside EOF */
1439 return offset;
1440 }
1441
1442 /**
1443 * i_blocks_per_folio - How many blocks fit in this folio.
1444 * @inode: The inode which contains the blocks.
1445 * @folio: The folio.
1446 *
1447 * If the block size is larger than the size of this folio, return zero.
1448 *
1449 * Context: The caller should hold a refcount on the folio to prevent it
1450 * from being split.
1451 * Return: The number of filesystem blocks covered by this folio.
1452 */
1453 static inline
i_blocks_per_folio(struct inode * inode,struct folio * folio)1454 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
1455 {
1456 return folio_size(folio) >> inode->i_blkbits;
1457 }
1458
1459 static inline
i_blocks_per_page(struct inode * inode,struct page * page)1460 unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
1461 {
1462 return i_blocks_per_folio(inode, page_folio(page));
1463 }
1464 #endif /* _LINUX_PAGEMAP_H */
1465