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 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 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 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 */ 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 */ 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 */ 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 */ 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 */ 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 } 134 135 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 */ 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 */ 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 } 236 237 static inline void mapping_set_unevictable(struct address_space *mapping) 238 { 239 set_bit(AS_UNEVICTABLE, &mapping->flags); 240 } 241 242 static inline void mapping_clear_unevictable(struct address_space *mapping) 243 { 244 clear_bit(AS_UNEVICTABLE, &mapping->flags); 245 } 246 247 static inline bool mapping_unevictable(struct address_space *mapping) 248 { 249 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags); 250 } 251 252 static inline void mapping_set_exiting(struct address_space *mapping) 253 { 254 set_bit(AS_EXITING, &mapping->flags); 255 } 256 257 static inline int mapping_exiting(struct address_space *mapping) 258 { 259 return test_bit(AS_EXITING, &mapping->flags); 260 } 261 262 static inline void mapping_set_no_writeback_tags(struct address_space *mapping) 263 { 264 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 265 } 266 267 static inline int mapping_use_writeback_tags(struct address_space *mapping) 268 { 269 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 270 } 271 272 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. */ 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 */ 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 */ 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 */ 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 } 318 319 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 } 327 328 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 } 337 338 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 */ 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 } 371 372 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 */ 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 */ 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 */ 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 */ 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 */ 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 } 458 459 static inline void attach_page_private(struct page *page, void *data) 460 { 461 folio_attach_private(page_folio(page), data); 462 } 463 464 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 472 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order) 473 { 474 return folio_alloc(gfp, order); 475 } 476 #endif 477 478 static inline struct page *__page_cache_alloc(gfp_t gfp) 479 { 480 return &filemap_alloc_folio(gfp, 0)->page; 481 } 482 483 static inline struct page *page_cache_alloc(struct address_space *x) 484 { 485 return __page_cache_alloc(mapping_gfp_mask(x)); 486 } 487 488 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 */ 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 */ 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 */ 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 } 565 566 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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); 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 */ 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); 752 753 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 } 758 759 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 */ 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 */ 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 */ 800 static inline loff_t page_offset(struct page *page) 801 { 802 return ((loff_t)page->index) << PAGE_SHIFT; 803 } 804 805 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 */ 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 */ 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 */ 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); 844 845 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 }; 867 868 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 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 1032 static inline void wait_on_page_locked(struct page *page) 1033 { 1034 folio_wait_locked(page_folio(page)); 1035 } 1036 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); 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); 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); 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 */ 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 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 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 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 */ 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 */ 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 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 */ 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 */ 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 */ 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 */ 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 */ 1375 static inline size_t readahead_batch_length(struct readahead_control *rac) 1376 { 1377 return rac->_batch_count * PAGE_SIZE; 1378 } 1379 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 */ 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 */ 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 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 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