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
19struct folio_batch;
20
21unsigned long invalidate_mapping_pages(struct address_space *mapping,
22 pgoff_t start, pgoff_t end);
23
24static 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(mapping: inode->i_mapping, start: 0, end: -1);
29}
30int invalidate_inode_pages2(struct address_space *mapping);
31int invalidate_inode_pages2_range(struct address_space *mapping,
32 pgoff_t start, pgoff_t end);
33int kiocb_invalidate_pages(struct kiocb *iocb, size_t count);
34void kiocb_invalidate_post_direct_write(struct kiocb *iocb, size_t count);
35
36int write_inode_now(struct inode *, int sync);
37int filemap_fdatawrite(struct address_space *);
38int filemap_flush(struct address_space *);
39int filemap_fdatawait_keep_errors(struct address_space *mapping);
40int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
41int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
42 loff_t start_byte, loff_t end_byte);
43
44static inline int filemap_fdatawait(struct address_space *mapping)
45{
46 return filemap_fdatawait_range(mapping, lstart: 0, LLONG_MAX);
47}
48
49bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend);
50int filemap_write_and_wait_range(struct address_space *mapping,
51 loff_t lstart, loff_t lend);
52int __filemap_fdatawrite_range(struct address_space *mapping,
53 loff_t start, loff_t end, int sync_mode);
54int filemap_fdatawrite_range(struct address_space *mapping,
55 loff_t start, loff_t end);
56int filemap_check_errors(struct address_space *mapping);
57void __filemap_set_wb_err(struct address_space *mapping, int err);
58int filemap_fdatawrite_wbc(struct address_space *mapping,
59 struct writeback_control *wbc);
60int kiocb_write_and_wait(struct kiocb *iocb, size_t count);
61
62static inline int filemap_write_and_wait(struct address_space *mapping)
63{
64 return filemap_write_and_wait_range(mapping, lstart: 0, LLONG_MAX);
65}
66
67/**
68 * filemap_set_wb_err - set a writeback error on an address_space
69 * @mapping: mapping in which to set writeback error
70 * @err: error to be set in mapping
71 *
72 * When writeback fails in some way, we must record that error so that
73 * userspace can be informed when fsync and the like are called. We endeavor
74 * to report errors on any file that was open at the time of the error. Some
75 * internal callers also need to know when writeback errors have occurred.
76 *
77 * When a writeback error occurs, most filesystems will want to call
78 * filemap_set_wb_err to record the error in the mapping so that it will be
79 * automatically reported whenever fsync is called on the file.
80 */
81static inline void filemap_set_wb_err(struct address_space *mapping, int err)
82{
83 /* Fastpath for common case of no error */
84 if (unlikely(err))
85 __filemap_set_wb_err(mapping, err);
86}
87
88/**
89 * filemap_check_wb_err - has an error occurred since the mark was sampled?
90 * @mapping: mapping to check for writeback errors
91 * @since: previously-sampled errseq_t
92 *
93 * Grab the errseq_t value from the mapping, and see if it has changed "since"
94 * the given value was sampled.
95 *
96 * If it has then report the latest error set, otherwise return 0.
97 */
98static inline int filemap_check_wb_err(struct address_space *mapping,
99 errseq_t since)
100{
101 return errseq_check(eseq: &mapping->wb_err, since);
102}
103
104/**
105 * filemap_sample_wb_err - sample the current errseq_t to test for later errors
106 * @mapping: mapping to be sampled
107 *
108 * Writeback errors are always reported relative to a particular sample point
109 * in the past. This function provides those sample points.
110 */
111static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
112{
113 return errseq_sample(eseq: &mapping->wb_err);
114}
115
116/**
117 * file_sample_sb_err - sample the current errseq_t to test for later errors
118 * @file: file pointer to be sampled
119 *
120 * Grab the most current superblock-level errseq_t value for the given
121 * struct file.
122 */
123static inline errseq_t file_sample_sb_err(struct file *file)
124{
125 return errseq_sample(eseq: &file->f_path.dentry->d_sb->s_wb_err);
126}
127
128/*
129 * Flush file data before changing attributes. Caller must hold any locks
130 * required to prevent further writes to this file until we're done setting
131 * flags.
132 */
133static inline int inode_drain_writes(struct inode *inode)
134{
135 inode_dio_wait(inode);
136 return filemap_write_and_wait(mapping: inode->i_mapping);
137}
138
139static inline bool mapping_empty(struct address_space *mapping)
140{
141 return xa_empty(xa: &mapping->i_pages);
142}
143
144/*
145 * mapping_shrinkable - test if page cache state allows inode reclaim
146 * @mapping: the page cache mapping
147 *
148 * This checks the mapping's cache state for the pupose of inode
149 * reclaim and LRU management.
150 *
151 * The caller is expected to hold the i_lock, but is not required to
152 * hold the i_pages lock, which usually protects cache state. That's
153 * because the i_lock and the list_lru lock that protect the inode and
154 * its LRU state don't nest inside the irq-safe i_pages lock.
155 *
156 * Cache deletions are performed under the i_lock, which ensures that
157 * when an inode goes empty, it will reliably get queued on the LRU.
158 *
159 * Cache additions do not acquire the i_lock and may race with this
160 * check, in which case we'll report the inode as shrinkable when it
161 * has cache pages. This is okay: the shrinker also checks the
162 * refcount and the referenced bit, which will be elevated or set in
163 * the process of adding new cache pages to an inode.
164 */
165static inline bool mapping_shrinkable(struct address_space *mapping)
166{
167 void *head;
168
169 /*
170 * On highmem systems, there could be lowmem pressure from the
171 * inodes before there is highmem pressure from the page
172 * cache. Make inodes shrinkable regardless of cache state.
173 */
174 if (IS_ENABLED(CONFIG_HIGHMEM))
175 return true;
176
177 /* Cache completely empty? Shrink away. */
178 head = rcu_access_pointer(mapping->i_pages.xa_head);
179 if (!head)
180 return true;
181
182 /*
183 * The xarray stores single offset-0 entries directly in the
184 * head pointer, which allows non-resident page cache entries
185 * to escape the shadow shrinker's list of xarray nodes. The
186 * inode shrinker needs to pick them up under memory pressure.
187 */
188 if (!xa_is_node(entry: head) && xa_is_value(entry: head))
189 return true;
190
191 return false;
192}
193
194/*
195 * Bits in mapping->flags.
196 */
197enum mapping_flags {
198 AS_EIO = 0, /* IO error on async write */
199 AS_ENOSPC = 1, /* ENOSPC on async write */
200 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
201 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
202 AS_EXITING = 4, /* final truncate in progress */
203 /* writeback related tags are not used */
204 AS_NO_WRITEBACK_TAGS = 5,
205 AS_LARGE_FOLIO_SUPPORT = 6,
206 AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */
207};
208
209/**
210 * mapping_set_error - record a writeback error in the address_space
211 * @mapping: the mapping in which an error should be set
212 * @error: the error to set in the mapping
213 *
214 * When writeback fails in some way, we must record that error so that
215 * userspace can be informed when fsync and the like are called. We endeavor
216 * to report errors on any file that was open at the time of the error. Some
217 * internal callers also need to know when writeback errors have occurred.
218 *
219 * When a writeback error occurs, most filesystems will want to call
220 * mapping_set_error to record the error in the mapping so that it can be
221 * reported when the application calls fsync(2).
222 */
223static inline void mapping_set_error(struct address_space *mapping, int error)
224{
225 if (likely(!error))
226 return;
227
228 /* Record in wb_err for checkers using errseq_t based tracking */
229 __filemap_set_wb_err(mapping, err: error);
230
231 /* Record it in superblock */
232 if (mapping->host)
233 errseq_set(eseq: &mapping->host->i_sb->s_wb_err, err: error);
234
235 /* Record it in flags for now, for legacy callers */
236 if (error == -ENOSPC)
237 set_bit(nr: AS_ENOSPC, addr: &mapping->flags);
238 else
239 set_bit(nr: AS_EIO, addr: &mapping->flags);
240}
241
242static inline void mapping_set_unevictable(struct address_space *mapping)
243{
244 set_bit(nr: AS_UNEVICTABLE, addr: &mapping->flags);
245}
246
247static inline void mapping_clear_unevictable(struct address_space *mapping)
248{
249 clear_bit(nr: AS_UNEVICTABLE, addr: &mapping->flags);
250}
251
252static inline bool mapping_unevictable(struct address_space *mapping)
253{
254 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
255}
256
257static inline void mapping_set_exiting(struct address_space *mapping)
258{
259 set_bit(nr: AS_EXITING, addr: &mapping->flags);
260}
261
262static inline int mapping_exiting(struct address_space *mapping)
263{
264 return test_bit(AS_EXITING, &mapping->flags);
265}
266
267static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
268{
269 set_bit(nr: AS_NO_WRITEBACK_TAGS, addr: &mapping->flags);
270}
271
272static inline int mapping_use_writeback_tags(struct address_space *mapping)
273{
274 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
275}
276
277static inline bool mapping_release_always(const struct address_space *mapping)
278{
279 return test_bit(AS_RELEASE_ALWAYS, &mapping->flags);
280}
281
282static inline void mapping_set_release_always(struct address_space *mapping)
283{
284 set_bit(nr: AS_RELEASE_ALWAYS, addr: &mapping->flags);
285}
286
287static inline void mapping_clear_release_always(struct address_space *mapping)
288{
289 clear_bit(nr: AS_RELEASE_ALWAYS, addr: &mapping->flags);
290}
291
292static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
293{
294 return mapping->gfp_mask;
295}
296
297/* Restricts the given gfp_mask to what the mapping allows. */
298static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
299 gfp_t gfp_mask)
300{
301 return mapping_gfp_mask(mapping) & gfp_mask;
302}
303
304/*
305 * This is non-atomic. Only to be used before the mapping is activated.
306 * Probably needs a barrier...
307 */
308static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
309{
310 m->gfp_mask = mask;
311}
312
313/**
314 * mapping_set_large_folios() - Indicate the file supports large folios.
315 * @mapping: The file.
316 *
317 * The filesystem should call this function in its inode constructor to
318 * indicate that the VFS can use large folios to cache the contents of
319 * the file.
320 *
321 * Context: This should not be called while the inode is active as it
322 * is non-atomic.
323 */
324static inline void mapping_set_large_folios(struct address_space *mapping)
325{
326 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
327}
328
329/*
330 * Large folio support currently depends on THP. These dependencies are
331 * being worked on but are not yet fixed.
332 */
333static inline bool mapping_large_folio_support(struct address_space *mapping)
334{
335 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
336 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
337}
338
339static inline int filemap_nr_thps(struct address_space *mapping)
340{
341#ifdef CONFIG_READ_ONLY_THP_FOR_FS
342 return atomic_read(v: &mapping->nr_thps);
343#else
344 return 0;
345#endif
346}
347
348static inline void filemap_nr_thps_inc(struct address_space *mapping)
349{
350#ifdef CONFIG_READ_ONLY_THP_FOR_FS
351 if (!mapping_large_folio_support(mapping))
352 atomic_inc(v: &mapping->nr_thps);
353#else
354 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
355#endif
356}
357
358static inline void filemap_nr_thps_dec(struct address_space *mapping)
359{
360#ifdef CONFIG_READ_ONLY_THP_FOR_FS
361 if (!mapping_large_folio_support(mapping))
362 atomic_dec(v: &mapping->nr_thps);
363#else
364 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
365#endif
366}
367
368struct address_space *page_mapping(struct page *);
369struct address_space *folio_mapping(struct folio *);
370struct address_space *swapcache_mapping(struct folio *);
371
372/**
373 * folio_file_mapping - Find the mapping this folio belongs to.
374 * @folio: The folio.
375 *
376 * For folios which are in the page cache, return the mapping that this
377 * page belongs to. Folios in the swap cache return the mapping of the
378 * swap file or swap device where the data is stored. This is different
379 * from the mapping returned by folio_mapping(). The only reason to
380 * use it is if, like NFS, you return 0 from ->activate_swapfile.
381 *
382 * Do not call this for folios which aren't in the page cache or swap cache.
383 */
384static inline struct address_space *folio_file_mapping(struct folio *folio)
385{
386 if (unlikely(folio_test_swapcache(folio)))
387 return swapcache_mapping(folio);
388
389 return folio->mapping;
390}
391
392/**
393 * folio_flush_mapping - Find the file mapping this folio belongs to.
394 * @folio: The folio.
395 *
396 * For folios which are in the page cache, return the mapping that this
397 * page belongs to. Anonymous folios return NULL, even if they're in
398 * the swap cache. Other kinds of folio also return NULL.
399 *
400 * This is ONLY used by architecture cache flushing code. If you aren't
401 * writing cache flushing code, you want either folio_mapping() or
402 * folio_file_mapping().
403 */
404static inline struct address_space *folio_flush_mapping(struct folio *folio)
405{
406 if (unlikely(folio_test_swapcache(folio)))
407 return NULL;
408
409 return folio_mapping(folio);
410}
411
412static inline struct address_space *page_file_mapping(struct page *page)
413{
414 return folio_file_mapping(page_folio(page));
415}
416
417/**
418 * folio_inode - Get the host inode for this folio.
419 * @folio: The folio.
420 *
421 * For folios which are in the page cache, return the inode that this folio
422 * belongs to.
423 *
424 * Do not call this for folios which aren't in the page cache.
425 */
426static inline struct inode *folio_inode(struct folio *folio)
427{
428 return folio->mapping->host;
429}
430
431/**
432 * folio_attach_private - Attach private data to a folio.
433 * @folio: Folio to attach data to.
434 * @data: Data to attach to folio.
435 *
436 * Attaching private data to a folio increments the page's reference count.
437 * The data must be detached before the folio will be freed.
438 */
439static inline void folio_attach_private(struct folio *folio, void *data)
440{
441 folio_get(folio);
442 folio->private = data;
443 folio_set_private(folio);
444}
445
446/**
447 * folio_change_private - Change private data on a folio.
448 * @folio: Folio to change the data on.
449 * @data: Data to set on the folio.
450 *
451 * Change the private data attached to a folio and return the old
452 * data. The page must previously have had data attached and the data
453 * must be detached before the folio will be freed.
454 *
455 * Return: Data that was previously attached to the folio.
456 */
457static inline void *folio_change_private(struct folio *folio, void *data)
458{
459 void *old = folio_get_private(folio);
460
461 folio->private = data;
462 return old;
463}
464
465/**
466 * folio_detach_private - Detach private data from a folio.
467 * @folio: Folio to detach data from.
468 *
469 * Removes the data that was previously attached to the folio and decrements
470 * the refcount on the page.
471 *
472 * Return: Data that was attached to the folio.
473 */
474static inline void *folio_detach_private(struct folio *folio)
475{
476 void *data = folio_get_private(folio);
477
478 if (!folio_test_private(folio))
479 return NULL;
480 folio_clear_private(folio);
481 folio->private = NULL;
482 folio_put(folio);
483
484 return data;
485}
486
487static inline void attach_page_private(struct page *page, void *data)
488{
489 folio_attach_private(page_folio(page), data);
490}
491
492static inline void *detach_page_private(struct page *page)
493{
494 return folio_detach_private(page_folio(page));
495}
496
497/*
498 * There are some parts of the kernel which assume that PMD entries
499 * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then,
500 * limit the maximum allocation order to PMD size. I'm not aware of any
501 * assumptions about maximum order if THP are disabled, but 8 seems like
502 * a good order (that's 1MB if you're using 4kB pages)
503 */
504#ifdef CONFIG_TRANSPARENT_HUGEPAGE
505#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER
506#else
507#define MAX_PAGECACHE_ORDER 8
508#endif
509
510#ifdef CONFIG_NUMA
511struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
512#else
513static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
514{
515 return folio_alloc(gfp, order);
516}
517#endif
518
519static inline struct page *__page_cache_alloc(gfp_t gfp)
520{
521 return &filemap_alloc_folio(gfp, order: 0)->page;
522}
523
524static inline struct page *page_cache_alloc(struct address_space *x)
525{
526 return __page_cache_alloc(gfp: mapping_gfp_mask(mapping: x));
527}
528
529static inline gfp_t readahead_gfp_mask(struct address_space *x)
530{
531 return mapping_gfp_mask(mapping: x) | __GFP_NORETRY | __GFP_NOWARN;
532}
533
534typedef int filler_t(struct file *, struct folio *);
535
536pgoff_t page_cache_next_miss(struct address_space *mapping,
537 pgoff_t index, unsigned long max_scan);
538pgoff_t page_cache_prev_miss(struct address_space *mapping,
539 pgoff_t index, unsigned long max_scan);
540
541/**
542 * typedef fgf_t - Flags for getting folios from the page cache.
543 *
544 * Most users of the page cache will not need to use these flags;
545 * there are convenience functions such as filemap_get_folio() and
546 * filemap_lock_folio(). For users which need more control over exactly
547 * what is done with the folios, these flags to __filemap_get_folio()
548 * are available.
549 *
550 * * %FGP_ACCESSED - The folio will be marked accessed.
551 * * %FGP_LOCK - The folio is returned locked.
552 * * %FGP_CREAT - If no folio is present then a new folio is allocated,
553 * added to the page cache and the VM's LRU list. The folio is
554 * returned locked.
555 * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
556 * folio is already in cache. If the folio was allocated, unlock it
557 * before returning so the caller can do the same dance.
558 * * %FGP_WRITE - The folio will be written to by the caller.
559 * * %FGP_NOFS - __GFP_FS will get cleared in gfp.
560 * * %FGP_NOWAIT - Don't block on the folio lock.
561 * * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
562 * * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
563 * implementation.
564 */
565typedef unsigned int __bitwise fgf_t;
566
567#define FGP_ACCESSED ((__force fgf_t)0x00000001)
568#define FGP_LOCK ((__force fgf_t)0x00000002)
569#define FGP_CREAT ((__force fgf_t)0x00000004)
570#define FGP_WRITE ((__force fgf_t)0x00000008)
571#define FGP_NOFS ((__force fgf_t)0x00000010)
572#define FGP_NOWAIT ((__force fgf_t)0x00000020)
573#define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
574#define FGP_STABLE ((__force fgf_t)0x00000080)
575#define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
576
577#define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
578
579/**
580 * fgf_set_order - Encode a length in the fgf_t flags.
581 * @size: The suggested size of the folio to create.
582 *
583 * The caller of __filemap_get_folio() can use this to suggest a preferred
584 * size for the folio that is created. If there is already a folio at
585 * the index, it will be returned, no matter what its size. If a folio
586 * is freshly created, it may be of a different size than requested
587 * due to alignment constraints, memory pressure, or the presence of
588 * other folios at nearby indices.
589 */
590static inline fgf_t fgf_set_order(size_t size)
591{
592 unsigned int shift = ilog2(size);
593
594 if (shift <= PAGE_SHIFT)
595 return 0;
596 return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
597}
598
599void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
600struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
601 fgf_t fgp_flags, gfp_t gfp);
602struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
603 fgf_t fgp_flags, gfp_t gfp);
604
605/**
606 * filemap_get_folio - Find and get a folio.
607 * @mapping: The address_space to search.
608 * @index: The page index.
609 *
610 * Looks up the page cache entry at @mapping & @index. If a folio is
611 * present, it is returned with an increased refcount.
612 *
613 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
614 * this index. Will not return a shadow, swap or DAX entry.
615 */
616static inline struct folio *filemap_get_folio(struct address_space *mapping,
617 pgoff_t index)
618{
619 return __filemap_get_folio(mapping, index, fgp_flags: 0, gfp: 0);
620}
621
622/**
623 * filemap_lock_folio - Find and lock a folio.
624 * @mapping: The address_space to search.
625 * @index: The page index.
626 *
627 * Looks up the page cache entry at @mapping & @index. If a folio is
628 * present, it is returned locked with an increased refcount.
629 *
630 * Context: May sleep.
631 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
632 * this index. Will not return a shadow, swap or DAX entry.
633 */
634static inline struct folio *filemap_lock_folio(struct address_space *mapping,
635 pgoff_t index)
636{
637 return __filemap_get_folio(mapping, index, FGP_LOCK, gfp: 0);
638}
639
640/**
641 * filemap_grab_folio - grab a folio from the page cache
642 * @mapping: The address space to search
643 * @index: The page index
644 *
645 * Looks up the page cache entry at @mapping & @index. If no folio is found,
646 * a new folio is created. The folio is locked, marked as accessed, and
647 * returned.
648 *
649 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found
650 * and failed to create a folio.
651 */
652static inline struct folio *filemap_grab_folio(struct address_space *mapping,
653 pgoff_t index)
654{
655 return __filemap_get_folio(mapping, index,
656 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
657 gfp: mapping_gfp_mask(mapping));
658}
659
660/**
661 * find_get_page - find and get a page reference
662 * @mapping: the address_space to search
663 * @offset: the page index
664 *
665 * Looks up the page cache slot at @mapping & @offset. If there is a
666 * page cache page, it is returned with an increased refcount.
667 *
668 * Otherwise, %NULL is returned.
669 */
670static inline struct page *find_get_page(struct address_space *mapping,
671 pgoff_t offset)
672{
673 return pagecache_get_page(mapping, index: offset, fgp_flags: 0, gfp: 0);
674}
675
676static inline struct page *find_get_page_flags(struct address_space *mapping,
677 pgoff_t offset, fgf_t fgp_flags)
678{
679 return pagecache_get_page(mapping, index: offset, fgp_flags, gfp: 0);
680}
681
682/**
683 * find_lock_page - locate, pin and lock a pagecache page
684 * @mapping: the address_space to search
685 * @index: the page index
686 *
687 * Looks up the page cache entry at @mapping & @index. If there is a
688 * page cache page, it is returned locked and with an increased
689 * refcount.
690 *
691 * Context: May sleep.
692 * Return: A struct page or %NULL if there is no page in the cache for this
693 * index.
694 */
695static inline struct page *find_lock_page(struct address_space *mapping,
696 pgoff_t index)
697{
698 return pagecache_get_page(mapping, index, FGP_LOCK, gfp: 0);
699}
700
701/**
702 * find_or_create_page - locate or add a pagecache page
703 * @mapping: the page's address_space
704 * @index: the page's index into the mapping
705 * @gfp_mask: page allocation mode
706 *
707 * Looks up the page cache slot at @mapping & @offset. If there is a
708 * page cache page, it is returned locked and with an increased
709 * refcount.
710 *
711 * If the page is not present, a new page is allocated using @gfp_mask
712 * and added to the page cache and the VM's LRU list. The page is
713 * returned locked and with an increased refcount.
714 *
715 * On memory exhaustion, %NULL is returned.
716 *
717 * find_or_create_page() may sleep, even if @gfp_flags specifies an
718 * atomic allocation!
719 */
720static inline struct page *find_or_create_page(struct address_space *mapping,
721 pgoff_t index, gfp_t gfp_mask)
722{
723 return pagecache_get_page(mapping, index,
724 FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
725 gfp: gfp_mask);
726}
727
728/**
729 * grab_cache_page_nowait - returns locked page at given index in given cache
730 * @mapping: target address_space
731 * @index: the page index
732 *
733 * Same as grab_cache_page(), but do not wait if the page is unavailable.
734 * This is intended for speculative data generators, where the data can
735 * be regenerated if the page couldn't be grabbed. This routine should
736 * be safe to call while holding the lock for another page.
737 *
738 * Clear __GFP_FS when allocating the page to avoid recursion into the fs
739 * and deadlock against the caller's locked page.
740 */
741static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
742 pgoff_t index)
743{
744 return pagecache_get_page(mapping, index,
745 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
746 gfp: mapping_gfp_mask(mapping));
747}
748
749#define swapcache_index(folio) __page_file_index(&(folio)->page)
750
751/**
752 * folio_index - File index of a folio.
753 * @folio: The folio.
754 *
755 * For a folio which is either in the page cache or the swap cache,
756 * return its index within the address_space it belongs to. If you know
757 * the page is definitely in the page cache, you can look at the folio's
758 * index directly.
759 *
760 * Return: The index (offset in units of pages) of a folio in its file.
761 */
762static inline pgoff_t folio_index(struct folio *folio)
763{
764 if (unlikely(folio_test_swapcache(folio)))
765 return swapcache_index(folio);
766 return folio->index;
767}
768
769/**
770 * folio_next_index - Get the index of the next folio.
771 * @folio: The current folio.
772 *
773 * Return: The index of the folio which follows this folio in the file.
774 */
775static inline pgoff_t folio_next_index(struct folio *folio)
776{
777 return folio->index + folio_nr_pages(folio);
778}
779
780/**
781 * folio_file_page - The page for a particular index.
782 * @folio: The folio which contains this index.
783 * @index: The index we want to look up.
784 *
785 * Sometimes after looking up a folio in the page cache, we need to
786 * obtain the specific page for an index (eg a page fault).
787 *
788 * Return: The page containing the file data for this index.
789 */
790static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
791{
792 return folio_page(folio, index & (folio_nr_pages(folio) - 1));
793}
794
795/**
796 * folio_contains - Does this folio contain this index?
797 * @folio: The folio.
798 * @index: The page index within the file.
799 *
800 * Context: The caller should have the page locked in order to prevent
801 * (eg) shmem from moving the page between the page cache and swap cache
802 * and changing its index in the middle of the operation.
803 * Return: true or false.
804 */
805static inline bool folio_contains(struct folio *folio, pgoff_t index)
806{
807 return index - folio_index(folio) < folio_nr_pages(folio);
808}
809
810/*
811 * Given the page we found in the page cache, return the page corresponding
812 * to this index in the file
813 */
814static inline struct page *find_subpage(struct page *head, pgoff_t index)
815{
816 /* HugeTLBfs wants the head page regardless */
817 if (PageHuge(page: head))
818 return head;
819
820 return head + (index & (thp_nr_pages(page: head) - 1));
821}
822
823unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
824 pgoff_t end, struct folio_batch *fbatch);
825unsigned filemap_get_folios_contig(struct address_space *mapping,
826 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
827unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
828 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch);
829
830struct page *grab_cache_page_write_begin(struct address_space *mapping,
831 pgoff_t index);
832
833/*
834 * Returns locked page at given index in given cache, creating it if needed.
835 */
836static inline struct page *grab_cache_page(struct address_space *mapping,
837 pgoff_t index)
838{
839 return find_or_create_page(mapping, index, gfp_mask: mapping_gfp_mask(mapping));
840}
841
842struct folio *read_cache_folio(struct address_space *, pgoff_t index,
843 filler_t *filler, struct file *file);
844struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
845 gfp_t flags);
846struct page *read_cache_page(struct address_space *, pgoff_t index,
847 filler_t *filler, struct file *file);
848extern struct page * read_cache_page_gfp(struct address_space *mapping,
849 pgoff_t index, gfp_t gfp_mask);
850
851static inline struct page *read_mapping_page(struct address_space *mapping,
852 pgoff_t index, struct file *file)
853{
854 return read_cache_page(mapping, index, NULL, file);
855}
856
857static inline struct folio *read_mapping_folio(struct address_space *mapping,
858 pgoff_t index, struct file *file)
859{
860 return read_cache_folio(mapping, index, NULL, file);
861}
862
863/*
864 * Get the offset in PAGE_SIZE (even for hugetlb pages).
865 */
866static inline pgoff_t page_to_pgoff(struct page *page)
867{
868 struct page *head;
869
870 if (likely(!PageTransTail(page)))
871 return page->index;
872
873 head = compound_head(page);
874 /*
875 * We don't initialize ->index for tail pages: calculate based on
876 * head page
877 */
878 return head->index + page - head;
879}
880
881/*
882 * Return byte-offset into filesystem object for page.
883 */
884static inline loff_t page_offset(struct page *page)
885{
886 return ((loff_t)page->index) << PAGE_SHIFT;
887}
888
889static inline loff_t page_file_offset(struct page *page)
890{
891 return ((loff_t)page_index(page)) << PAGE_SHIFT;
892}
893
894/**
895 * folio_pos - Returns the byte position of this folio in its file.
896 * @folio: The folio.
897 */
898static inline loff_t folio_pos(struct folio *folio)
899{
900 return page_offset(page: &folio->page);
901}
902
903/**
904 * folio_file_pos - Returns the byte position of this folio in its file.
905 * @folio: The folio.
906 *
907 * This differs from folio_pos() for folios which belong to a swap file.
908 * NFS is the only filesystem today which needs to use folio_file_pos().
909 */
910static inline loff_t folio_file_pos(struct folio *folio)
911{
912 return page_file_offset(page: &folio->page);
913}
914
915/*
916 * Get the offset in PAGE_SIZE (even for hugetlb folios).
917 */
918static inline pgoff_t folio_pgoff(struct folio *folio)
919{
920 return folio->index;
921}
922
923static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
924 unsigned long address)
925{
926 pgoff_t pgoff;
927 pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
928 pgoff += vma->vm_pgoff;
929 return pgoff;
930}
931
932struct wait_page_key {
933 struct folio *folio;
934 int bit_nr;
935 int page_match;
936};
937
938struct wait_page_queue {
939 struct folio *folio;
940 int bit_nr;
941 wait_queue_entry_t wait;
942};
943
944static inline bool wake_page_match(struct wait_page_queue *wait_page,
945 struct wait_page_key *key)
946{
947 if (wait_page->folio != key->folio)
948 return false;
949 key->page_match = 1;
950
951 if (wait_page->bit_nr != key->bit_nr)
952 return false;
953
954 return true;
955}
956
957void __folio_lock(struct folio *folio);
958int __folio_lock_killable(struct folio *folio);
959vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
960void unlock_page(struct page *page);
961void folio_unlock(struct folio *folio);
962
963/**
964 * folio_trylock() - Attempt to lock a folio.
965 * @folio: The folio to attempt to lock.
966 *
967 * Sometimes it is undesirable to wait for a folio to be unlocked (eg
968 * when the locks are being taken in the wrong order, or if making
969 * progress through a batch of folios is more important than processing
970 * them in order). Usually folio_lock() is the correct function to call.
971 *
972 * Context: Any context.
973 * Return: Whether the lock was successfully acquired.
974 */
975static inline bool folio_trylock(struct folio *folio)
976{
977 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
978}
979
980/*
981 * Return true if the page was successfully locked
982 */
983static inline int trylock_page(struct page *page)
984{
985 return folio_trylock(page_folio(page));
986}
987
988/**
989 * folio_lock() - Lock this folio.
990 * @folio: The folio to lock.
991 *
992 * The folio lock protects against many things, probably more than it
993 * should. It is primarily held while a folio is being brought uptodate,
994 * either from its backing file or from swap. It is also held while a
995 * folio is being truncated from its address_space, so holding the lock
996 * is sufficient to keep folio->mapping stable.
997 *
998 * The folio lock is also held while write() is modifying the page to
999 * provide POSIX atomicity guarantees (as long as the write does not
1000 * cross a page boundary). Other modifications to the data in the folio
1001 * do not hold the folio lock and can race with writes, eg DMA and stores
1002 * to mapped pages.
1003 *
1004 * Context: May sleep. If you need to acquire the locks of two or
1005 * more folios, they must be in order of ascending index, if they are
1006 * in the same address_space. If they are in different address_spaces,
1007 * acquire the lock of the folio which belongs to the address_space which
1008 * has the lowest address in memory first.
1009 */
1010static inline void folio_lock(struct folio *folio)
1011{
1012 might_sleep();
1013 if (!folio_trylock(folio))
1014 __folio_lock(folio);
1015}
1016
1017/**
1018 * lock_page() - Lock the folio containing this page.
1019 * @page: The page to lock.
1020 *
1021 * See folio_lock() for a description of what the lock protects.
1022 * This is a legacy function and new code should probably use folio_lock()
1023 * instead.
1024 *
1025 * Context: May sleep. Pages in the same folio share a lock, so do not
1026 * attempt to lock two pages which share a folio.
1027 */
1028static inline void lock_page(struct page *page)
1029{
1030 struct folio *folio;
1031 might_sleep();
1032
1033 folio = page_folio(page);
1034 if (!folio_trylock(folio))
1035 __folio_lock(folio);
1036}
1037
1038/**
1039 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
1040 * @folio: The folio to lock.
1041 *
1042 * Attempts to lock the folio, like folio_lock(), except that the sleep
1043 * to acquire the lock is interruptible by a fatal signal.
1044 *
1045 * Context: May sleep; see folio_lock().
1046 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
1047 */
1048static inline int folio_lock_killable(struct folio *folio)
1049{
1050 might_sleep();
1051 if (!folio_trylock(folio))
1052 return __folio_lock_killable(folio);
1053 return 0;
1054}
1055
1056/*
1057 * folio_lock_or_retry - Lock the folio, unless this would block and the
1058 * caller indicated that it can handle a retry.
1059 *
1060 * Return value and mmap_lock implications depend on flags; see
1061 * __folio_lock_or_retry().
1062 */
1063static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
1064 struct vm_fault *vmf)
1065{
1066 might_sleep();
1067 if (!folio_trylock(folio))
1068 return __folio_lock_or_retry(folio, vmf);
1069 return 0;
1070}
1071
1072/*
1073 * This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
1074 * and should not be used directly.
1075 */
1076void folio_wait_bit(struct folio *folio, int bit_nr);
1077int folio_wait_bit_killable(struct folio *folio, int bit_nr);
1078
1079/*
1080 * Wait for a folio to be unlocked.
1081 *
1082 * This must be called with the caller "holding" the folio,
1083 * ie with increased folio reference count so that the folio won't
1084 * go away during the wait.
1085 */
1086static inline void folio_wait_locked(struct folio *folio)
1087{
1088 if (folio_test_locked(folio))
1089 folio_wait_bit(folio, bit_nr: PG_locked);
1090}
1091
1092static inline int folio_wait_locked_killable(struct folio *folio)
1093{
1094 if (!folio_test_locked(folio))
1095 return 0;
1096 return folio_wait_bit_killable(folio, bit_nr: PG_locked);
1097}
1098
1099static inline void wait_on_page_locked(struct page *page)
1100{
1101 folio_wait_locked(page_folio(page));
1102}
1103
1104void folio_end_read(struct folio *folio, bool success);
1105void wait_on_page_writeback(struct page *page);
1106void folio_wait_writeback(struct folio *folio);
1107int folio_wait_writeback_killable(struct folio *folio);
1108void end_page_writeback(struct page *page);
1109void folio_end_writeback(struct folio *folio);
1110void wait_for_stable_page(struct page *page);
1111void folio_wait_stable(struct folio *folio);
1112void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
1113static inline void __set_page_dirty(struct page *page,
1114 struct address_space *mapping, int warn)
1115{
1116 __folio_mark_dirty(page_folio(page), mapping, warn);
1117}
1118void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
1119void __folio_cancel_dirty(struct folio *folio);
1120static inline void folio_cancel_dirty(struct folio *folio)
1121{
1122 /* Avoid atomic ops, locking, etc. when not actually needed. */
1123 if (folio_test_dirty(folio))
1124 __folio_cancel_dirty(folio);
1125}
1126bool folio_clear_dirty_for_io(struct folio *folio);
1127bool clear_page_dirty_for_io(struct page *page);
1128void folio_invalidate(struct folio *folio, size_t offset, size_t length);
1129int __set_page_dirty_nobuffers(struct page *page);
1130bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
1131
1132#ifdef CONFIG_MIGRATION
1133int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
1134 struct folio *src, enum migrate_mode mode);
1135#else
1136#define filemap_migrate_folio NULL
1137#endif
1138void folio_end_private_2(struct folio *folio);
1139void folio_wait_private_2(struct folio *folio);
1140int folio_wait_private_2_killable(struct folio *folio);
1141
1142/*
1143 * Add an arbitrary waiter to a page's wait queue
1144 */
1145void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
1146
1147/*
1148 * Fault in userspace address range.
1149 */
1150size_t fault_in_writeable(char __user *uaddr, size_t size);
1151size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
1152size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
1153size_t fault_in_readable(const char __user *uaddr, size_t size);
1154
1155int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
1156 pgoff_t index, gfp_t gfp);
1157int filemap_add_folio(struct address_space *mapping, struct folio *folio,
1158 pgoff_t index, gfp_t gfp);
1159void filemap_remove_folio(struct folio *folio);
1160void __filemap_remove_folio(struct folio *folio, void *shadow);
1161void replace_page_cache_folio(struct folio *old, struct folio *new);
1162void delete_from_page_cache_batch(struct address_space *mapping,
1163 struct folio_batch *fbatch);
1164bool filemap_release_folio(struct folio *folio, gfp_t gfp);
1165loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
1166 int whence);
1167
1168/* Must be non-static for BPF error injection */
1169int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
1170 pgoff_t index, gfp_t gfp, void **shadowp);
1171
1172bool filemap_range_has_writeback(struct address_space *mapping,
1173 loff_t start_byte, loff_t end_byte);
1174
1175/**
1176 * filemap_range_needs_writeback - check if range potentially needs writeback
1177 * @mapping: address space within which to check
1178 * @start_byte: offset in bytes where the range starts
1179 * @end_byte: offset in bytes where the range ends (inclusive)
1180 *
1181 * Find at least one page in the range supplied, usually used to check if
1182 * direct writing in this range will trigger a writeback. Used by O_DIRECT
1183 * read/write with IOCB_NOWAIT, to see if the caller needs to do
1184 * filemap_write_and_wait_range() before proceeding.
1185 *
1186 * Return: %true if the caller should do filemap_write_and_wait_range() before
1187 * doing O_DIRECT to a page in this range, %false otherwise.
1188 */
1189static inline bool filemap_range_needs_writeback(struct address_space *mapping,
1190 loff_t start_byte,
1191 loff_t end_byte)
1192{
1193 if (!mapping->nrpages)
1194 return false;
1195 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
1196 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
1197 return false;
1198 return filemap_range_has_writeback(mapping, start_byte, end_byte);
1199}
1200
1201/**
1202 * struct readahead_control - Describes a readahead request.
1203 *
1204 * A readahead request is for consecutive pages. Filesystems which
1205 * implement the ->readahead method should call readahead_page() or
1206 * readahead_page_batch() in a loop and attempt to start I/O against
1207 * each page in the request.
1208 *
1209 * Most of the fields in this struct are private and should be accessed
1210 * by the functions below.
1211 *
1212 * @file: The file, used primarily by network filesystems for authentication.
1213 * May be NULL if invoked internally by the filesystem.
1214 * @mapping: Readahead this filesystem object.
1215 * @ra: File readahead state. May be NULL.
1216 */
1217struct readahead_control {
1218 struct file *file;
1219 struct address_space *mapping;
1220 struct file_ra_state *ra;
1221/* private: use the readahead_* accessors instead */
1222 pgoff_t _index;
1223 unsigned int _nr_pages;
1224 unsigned int _batch_count;
1225 bool _workingset;
1226 unsigned long _pflags;
1227};
1228
1229#define DEFINE_READAHEAD(ractl, f, r, m, i) \
1230 struct readahead_control ractl = { \
1231 .file = f, \
1232 .mapping = m, \
1233 .ra = r, \
1234 ._index = i, \
1235 }
1236
1237#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
1238
1239void page_cache_ra_unbounded(struct readahead_control *,
1240 unsigned long nr_to_read, unsigned long lookahead_count);
1241void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
1242void page_cache_async_ra(struct readahead_control *, struct folio *,
1243 unsigned long req_count);
1244void readahead_expand(struct readahead_control *ractl,
1245 loff_t new_start, size_t new_len);
1246
1247/**
1248 * page_cache_sync_readahead - generic file readahead
1249 * @mapping: address_space which holds the pagecache and I/O vectors
1250 * @ra: file_ra_state which holds the readahead state
1251 * @file: Used by the filesystem for authentication.
1252 * @index: Index of first page to be read.
1253 * @req_count: Total number of pages being read by the caller.
1254 *
1255 * page_cache_sync_readahead() should be called when a cache miss happened:
1256 * it will submit the read. The readahead logic may decide to piggyback more
1257 * pages onto the read request if access patterns suggest it will improve
1258 * performance.
1259 */
1260static inline
1261void page_cache_sync_readahead(struct address_space *mapping,
1262 struct file_ra_state *ra, struct file *file, pgoff_t index,
1263 unsigned long req_count)
1264{
1265 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1266 page_cache_sync_ra(&ractl, req_count);
1267}
1268
1269/**
1270 * page_cache_async_readahead - file readahead for marked pages
1271 * @mapping: address_space which holds the pagecache and I/O vectors
1272 * @ra: file_ra_state which holds the readahead state
1273 * @file: Used by the filesystem for authentication.
1274 * @folio: The folio at @index which triggered the readahead call.
1275 * @index: Index of first page to be read.
1276 * @req_count: Total number of pages being read by the caller.
1277 *
1278 * page_cache_async_readahead() should be called when a page is used which
1279 * is marked as PageReadahead; this is a marker to suggest that the application
1280 * has used up enough of the readahead window that we should start pulling in
1281 * more pages.
1282 */
1283static inline
1284void page_cache_async_readahead(struct address_space *mapping,
1285 struct file_ra_state *ra, struct file *file,
1286 struct folio *folio, pgoff_t index, unsigned long req_count)
1287{
1288 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1289 page_cache_async_ra(&ractl, folio, req_count);
1290}
1291
1292static inline struct folio *__readahead_folio(struct readahead_control *ractl)
1293{
1294 struct folio *folio;
1295
1296 BUG_ON(ractl->_batch_count > ractl->_nr_pages);
1297 ractl->_nr_pages -= ractl->_batch_count;
1298 ractl->_index += ractl->_batch_count;
1299
1300 if (!ractl->_nr_pages) {
1301 ractl->_batch_count = 0;
1302 return NULL;
1303 }
1304
1305 folio = xa_load(&ractl->mapping->i_pages, index: ractl->_index);
1306 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
1307 ractl->_batch_count = folio_nr_pages(folio);
1308
1309 return folio;
1310}
1311
1312/**
1313 * readahead_page - Get the next page to read.
1314 * @ractl: The current readahead request.
1315 *
1316 * Context: The page is locked and has an elevated refcount. The caller
1317 * should decreases the refcount once the page has been submitted for I/O
1318 * and unlock the page once all I/O to that page has completed.
1319 * Return: A pointer to the next page, or %NULL if we are done.
1320 */
1321static inline struct page *readahead_page(struct readahead_control *ractl)
1322{
1323 struct folio *folio = __readahead_folio(ractl);
1324
1325 return &folio->page;
1326}
1327
1328/**
1329 * readahead_folio - Get the next folio to read.
1330 * @ractl: The current readahead request.
1331 *
1332 * Context: The folio is locked. The caller should unlock the folio once
1333 * all I/O to that folio has completed.
1334 * Return: A pointer to the next folio, or %NULL if we are done.
1335 */
1336static inline struct folio *readahead_folio(struct readahead_control *ractl)
1337{
1338 struct folio *folio = __readahead_folio(ractl);
1339
1340 if (folio)
1341 folio_put(folio);
1342 return folio;
1343}
1344
1345static inline unsigned int __readahead_batch(struct readahead_control *rac,
1346 struct page **array, unsigned int array_sz)
1347{
1348 unsigned int i = 0;
1349 XA_STATE(xas, &rac->mapping->i_pages, 0);
1350 struct page *page;
1351
1352 BUG_ON(rac->_batch_count > rac->_nr_pages);
1353 rac->_nr_pages -= rac->_batch_count;
1354 rac->_index += rac->_batch_count;
1355 rac->_batch_count = 0;
1356
1357 xas_set(xas: &xas, index: rac->_index);
1358 rcu_read_lock();
1359 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
1360 if (xas_retry(xas: &xas, entry: page))
1361 continue;
1362 VM_BUG_ON_PAGE(!PageLocked(page), page);
1363 VM_BUG_ON_PAGE(PageTail(page), page);
1364 array[i++] = page;
1365 rac->_batch_count += thp_nr_pages(page);
1366 if (i == array_sz)
1367 break;
1368 }
1369 rcu_read_unlock();
1370
1371 return i;
1372}
1373
1374/**
1375 * readahead_page_batch - Get a batch of pages to read.
1376 * @rac: The current readahead request.
1377 * @array: An array of pointers to struct page.
1378 *
1379 * Context: The pages are locked and have an elevated refcount. The caller
1380 * should decreases the refcount once the page has been submitted for I/O
1381 * and unlock the page once all I/O to that page has completed.
1382 * Return: The number of pages placed in the array. 0 indicates the request
1383 * is complete.
1384 */
1385#define readahead_page_batch(rac, array) \
1386 __readahead_batch(rac, array, ARRAY_SIZE(array))
1387
1388/**
1389 * readahead_pos - The byte offset into the file of this readahead request.
1390 * @rac: The readahead request.
1391 */
1392static inline loff_t readahead_pos(struct readahead_control *rac)
1393{
1394 return (loff_t)rac->_index * PAGE_SIZE;
1395}
1396
1397/**
1398 * readahead_length - The number of bytes in this readahead request.
1399 * @rac: The readahead request.
1400 */
1401static inline size_t readahead_length(struct readahead_control *rac)
1402{
1403 return rac->_nr_pages * PAGE_SIZE;
1404}
1405
1406/**
1407 * readahead_index - The index of the first page in this readahead request.
1408 * @rac: The readahead request.
1409 */
1410static inline pgoff_t readahead_index(struct readahead_control *rac)
1411{
1412 return rac->_index;
1413}
1414
1415/**
1416 * readahead_count - The number of pages in this readahead request.
1417 * @rac: The readahead request.
1418 */
1419static inline unsigned int readahead_count(struct readahead_control *rac)
1420{
1421 return rac->_nr_pages;
1422}
1423
1424/**
1425 * readahead_batch_length - The number of bytes in the current batch.
1426 * @rac: The readahead request.
1427 */
1428static inline size_t readahead_batch_length(struct readahead_control *rac)
1429{
1430 return rac->_batch_count * PAGE_SIZE;
1431}
1432
1433static inline unsigned long dir_pages(struct inode *inode)
1434{
1435 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
1436 PAGE_SHIFT;
1437}
1438
1439/**
1440 * folio_mkwrite_check_truncate - check if folio was truncated
1441 * @folio: the folio to check
1442 * @inode: the inode to check the folio against
1443 *
1444 * Return: the number of bytes in the folio up to EOF,
1445 * or -EFAULT if the folio was truncated.
1446 */
1447static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
1448 struct inode *inode)
1449{
1450 loff_t size = i_size_read(inode);
1451 pgoff_t index = size >> PAGE_SHIFT;
1452 size_t offset = offset_in_folio(folio, size);
1453
1454 if (!folio->mapping)
1455 return -EFAULT;
1456
1457 /* folio is wholly inside EOF */
1458 if (folio_next_index(folio) - 1 < index)
1459 return folio_size(folio);
1460 /* folio is wholly past EOF */
1461 if (folio->index > index || !offset)
1462 return -EFAULT;
1463 /* folio is partially inside EOF */
1464 return offset;
1465}
1466
1467/**
1468 * page_mkwrite_check_truncate - check if page was truncated
1469 * @page: the page to check
1470 * @inode: the inode to check the page against
1471 *
1472 * Returns the number of bytes in the page up to EOF,
1473 * or -EFAULT if the page was truncated.
1474 */
1475static inline int page_mkwrite_check_truncate(struct page *page,
1476 struct inode *inode)
1477{
1478 loff_t size = i_size_read(inode);
1479 pgoff_t index = size >> PAGE_SHIFT;
1480 int offset = offset_in_page(size);
1481
1482 if (page->mapping != inode->i_mapping)
1483 return -EFAULT;
1484
1485 /* page is wholly inside EOF */
1486 if (page->index < index)
1487 return PAGE_SIZE;
1488 /* page is wholly past EOF */
1489 if (page->index > index || !offset)
1490 return -EFAULT;
1491 /* page is partially inside EOF */
1492 return offset;
1493}
1494
1495/**
1496 * i_blocks_per_folio - How many blocks fit in this folio.
1497 * @inode: The inode which contains the blocks.
1498 * @folio: The folio.
1499 *
1500 * If the block size is larger than the size of this folio, return zero.
1501 *
1502 * Context: The caller should hold a refcount on the folio to prevent it
1503 * from being split.
1504 * Return: The number of filesystem blocks covered by this folio.
1505 */
1506static inline
1507unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
1508{
1509 return folio_size(folio) >> inode->i_blkbits;
1510}
1511
1512static inline
1513unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
1514{
1515 return i_blocks_per_folio(inode, page_folio(page));
1516}
1517#endif /* _LINUX_PAGEMAP_H */
1518

source code of linux/include/linux/pagemap.h