xref: /linux/include/linux/hugetlb.h (revision 3c2d42b8ee345b17a4ba56b0f6492d1ff4c1178e)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_HUGETLB_H
3 #define _LINUX_HUGETLB_H
4 
5 #include <linux/mm.h>
6 #include <linux/mm_types.h>
7 #include <linux/mmdebug.h>
8 #include <linux/fs.h>
9 #include <linux/hugetlb_inline.h>
10 #include <linux/cgroup.h>
11 #include <linux/page_ref.h>
12 #include <linux/list.h>
13 #include <linux/kref.h>
14 #include <linux/pgtable.h>
15 #include <linux/gfp.h>
16 #include <linux/userfaultfd_k.h>
17 #include <linux/nodemask.h>
18 
19 struct mmu_gather;
20 struct node;
21 
22 void free_huge_folio(struct folio *folio);
23 
24 #ifdef CONFIG_HUGETLB_PAGE
25 
26 #include <linux/pagemap.h>
27 #include <linux/shm.h>
28 #include <asm/tlbflush.h>
29 
30 /*
31  * For HugeTLB page, there are more metadata to save in the struct page. But
32  * the head struct page cannot meet our needs, so we have to abuse other tail
33  * struct page to store the metadata.
34  */
35 #define __NR_USED_SUBPAGE 3
36 
37 struct hugepage_subpool {
38 	spinlock_t lock;
39 	long count;
40 	long max_hpages;	/* Maximum huge pages or -1 if no maximum. */
41 	long used_hpages;	/* Used count against maximum, includes */
42 				/* both allocated and reserved pages. */
43 	struct hstate *hstate;
44 	long min_hpages;	/* Minimum huge pages or -1 if no minimum. */
45 	long rsv_hpages;	/* Pages reserved against global pool to */
46 				/* satisfy minimum size. */
47 };
48 
49 struct resv_map {
50 	struct kref refs;
51 	spinlock_t lock;
52 	struct list_head regions;
53 	long adds_in_progress;
54 	struct list_head region_cache;
55 	long region_cache_count;
56 	struct rw_semaphore rw_sema;
57 #ifdef CONFIG_CGROUP_HUGETLB
58 	/*
59 	 * On private mappings, the counter to uncharge reservations is stored
60 	 * here. If these fields are 0, then either the mapping is shared, or
61 	 * cgroup accounting is disabled for this resv_map.
62 	 */
63 	struct page_counter *reservation_counter;
64 	unsigned long pages_per_hpage;
65 	struct cgroup_subsys_state *css;
66 #endif
67 };
68 
69 /*
70  * Region tracking -- allows tracking of reservations and instantiated pages
71  *                    across the pages in a mapping.
72  *
73  * The region data structures are embedded into a resv_map and protected
74  * by a resv_map's lock.  The set of regions within the resv_map represent
75  * reservations for huge pages, or huge pages that have already been
76  * instantiated within the map.  The from and to elements are huge page
77  * indices into the associated mapping.  from indicates the starting index
78  * of the region.  to represents the first index past the end of  the region.
79  *
80  * For example, a file region structure with from == 0 and to == 4 represents
81  * four huge pages in a mapping.  It is important to note that the to element
82  * represents the first element past the end of the region. This is used in
83  * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
84  *
85  * Interval notation of the form [from, to) will be used to indicate that
86  * the endpoint from is inclusive and to is exclusive.
87  */
88 struct file_region {
89 	struct list_head link;
90 	long from;
91 	long to;
92 #ifdef CONFIG_CGROUP_HUGETLB
93 	/*
94 	 * On shared mappings, each reserved region appears as a struct
95 	 * file_region in resv_map. These fields hold the info needed to
96 	 * uncharge each reservation.
97 	 */
98 	struct page_counter *reservation_counter;
99 	struct cgroup_subsys_state *css;
100 #endif
101 };
102 
103 struct hugetlb_vma_lock {
104 	struct kref refs;
105 	struct rw_semaphore rw_sema;
106 	struct vm_area_struct *vma;
107 };
108 
109 extern struct resv_map *resv_map_alloc(void);
110 void resv_map_release(struct kref *ref);
111 
112 extern spinlock_t hugetlb_lock;
113 extern int hugetlb_max_hstate __read_mostly;
114 #define for_each_hstate(h) \
115 	for ((h) = hstates; (h) < &hstates[hugetlb_max_hstate]; (h)++)
116 
117 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
118 						long min_hpages);
119 void hugepage_put_subpool(struct hugepage_subpool *spool);
120 
121 void hugetlb_dup_vma_private(struct vm_area_struct *vma);
122 void clear_vma_resv_huge_pages(struct vm_area_struct *vma);
123 int move_hugetlb_page_tables(struct vm_area_struct *vma,
124 			     struct vm_area_struct *new_vma,
125 			     unsigned long old_addr, unsigned long new_addr,
126 			     unsigned long len);
127 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
128 			    struct vm_area_struct *, struct vm_area_struct *);
129 void unmap_hugepage_range(struct vm_area_struct *,
130 			  unsigned long start, unsigned long end,
131 			  struct folio *, zap_flags_t);
132 void __unmap_hugepage_range(struct mmu_gather *tlb,
133 			  struct vm_area_struct *vma,
134 			  unsigned long start, unsigned long end,
135 			  struct folio *, zap_flags_t zap_flags);
136 void hugetlb_report_meminfo(struct seq_file *);
137 int hugetlb_report_node_meminfo(char *buf, int len, int nid);
138 void hugetlb_show_meminfo_node(int nid);
139 unsigned long hugetlb_total_pages(void);
140 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
141 			unsigned long address, unsigned int flags);
142 #ifdef CONFIG_USERFAULTFD
143 int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
144 			     struct vm_area_struct *dst_vma,
145 			     unsigned long dst_addr,
146 			     unsigned long src_addr,
147 			     uffd_flags_t flags,
148 			     struct folio **foliop);
149 #endif /* CONFIG_USERFAULTFD */
150 long hugetlb_reserve_pages(struct inode *inode, long from, long to,
151 			   struct vm_area_struct *vma, vma_flags_t vma_flags);
152 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
153 						long freed);
154 bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list);
155 int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
156 void folio_putback_hugetlb(struct folio *folio);
157 void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason);
158 void hugetlb_fix_reserve_counts(struct inode *inode);
159 extern struct mutex *hugetlb_fault_mutex_table;
160 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);
161 
162 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
163 		      unsigned long addr, pud_t *pud);
164 bool hugetlbfs_pagecache_present(struct hstate *h,
165 				 struct vm_area_struct *vma,
166 				 unsigned long address);
167 
168 struct address_space *hugetlb_folio_mapping_lock_write(struct folio *folio);
169 
170 extern int movable_gigantic_pages __read_mostly;
171 extern int sysctl_hugetlb_shm_group __read_mostly;
172 extern struct list_head huge_boot_pages[MAX_NUMNODES];
173 
174 void hugetlb_bootmem_alloc(void);
175 extern nodemask_t hugetlb_bootmem_nodes;
176 void hugetlb_bootmem_set_nodes(void);
177 
178 /* arch callbacks */
179 
180 #ifndef CONFIG_HIGHPTE
181 /*
182  * pte_offset_huge() and pte_alloc_huge() are helpers for those architectures
183  * which may go down to the lowest PTE level in their huge_pte_offset() and
184  * huge_pte_alloc(): to avoid reliance on pte_offset_map() without pte_unmap().
185  */
186 static inline pte_t *pte_offset_huge(pmd_t *pmd, unsigned long address)
187 {
188 	return pte_offset_kernel(pmd, address);
189 }
190 static inline pte_t *pte_alloc_huge(struct mm_struct *mm, pmd_t *pmd,
191 				    unsigned long address)
192 {
193 	return pte_alloc(mm, pmd) ? NULL : pte_offset_huge(pmd, address);
194 }
195 #endif
196 
197 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
198 			unsigned long addr, unsigned long sz);
199 /*
200  * huge_pte_offset(): Walk the hugetlb pgtable until the last level PTE.
201  * Returns the pte_t* if found, or NULL if the address is not mapped.
202  *
203  * IMPORTANT: we should normally not directly call this function, instead
204  * this is only a common interface to implement arch-specific
205  * walker. Please use hugetlb_walk() instead, because that will attempt to
206  * verify the locking for you.
207  *
208  * Since this function will walk all the pgtable pages (including not only
209  * high-level pgtable page, but also PUD entry that can be unshared
210  * concurrently for VM_SHARED), the caller of this function should be
211  * responsible of its thread safety.  One can follow this rule:
212  *
213  *  (1) For private mappings: pmd unsharing is not possible, so holding the
214  *      mmap_lock for either read or write is sufficient. Most callers
215  *      already hold the mmap_lock, so normally, no special action is
216  *      required.
217  *
218  *  (2) For shared mappings: pmd unsharing is possible (so the PUD-ranged
219  *      pgtable page can go away from under us!  It can be done by a pmd
220  *      unshare with a follow up munmap() on the other process), then we
221  *      need either:
222  *
223  *     (2.1) hugetlb vma lock read or write held, to make sure pmd unshare
224  *           won't happen upon the range (it also makes sure the pte_t we
225  *           read is the right and stable one), or,
226  *
227  *     (2.2) hugetlb mapping i_mmap_rwsem lock held read or write, to make
228  *           sure even if unshare happened the racy unmap() will wait until
229  *           i_mmap_rwsem is released.
230  *
231  * Option (2.1) is the safest, which guarantees pte stability from pmd
232  * sharing pov, until the vma lock released.  Option (2.2) doesn't protect
233  * a concurrent pmd unshare, but it makes sure the pgtable page is safe to
234  * access.
235  */
236 pte_t *huge_pte_offset(struct mm_struct *mm,
237 		       unsigned long addr, unsigned long sz);
238 unsigned long hugetlb_mask_last_page(struct hstate *h);
239 int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma,
240 		unsigned long addr, pte_t *ptep);
241 void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma);
242 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
243 				unsigned long *start, unsigned long *end);
244 
245 extern void __hugetlb_zap_begin(struct vm_area_struct *vma,
246 				unsigned long *begin, unsigned long *end);
247 extern void __hugetlb_zap_end(struct vm_area_struct *vma,
248 			      struct zap_details *details);
249 
250 static inline void hugetlb_zap_begin(struct vm_area_struct *vma,
251 				     unsigned long *start, unsigned long *end)
252 {
253 	if (is_vm_hugetlb_page(vma))
254 		__hugetlb_zap_begin(vma, start, end);
255 }
256 
257 static inline void hugetlb_zap_end(struct vm_area_struct *vma,
258 				   struct zap_details *details)
259 {
260 	if (is_vm_hugetlb_page(vma))
261 		__hugetlb_zap_end(vma, details);
262 }
263 
264 void hugetlb_vma_lock_read(struct vm_area_struct *vma);
265 void hugetlb_vma_unlock_read(struct vm_area_struct *vma);
266 void hugetlb_vma_lock_write(struct vm_area_struct *vma);
267 void hugetlb_vma_unlock_write(struct vm_area_struct *vma);
268 int hugetlb_vma_trylock_write(struct vm_area_struct *vma);
269 void hugetlb_vma_assert_locked(struct vm_area_struct *vma);
270 void hugetlb_vma_lock_release(struct kref *kref);
271 long hugetlb_change_protection(struct vm_area_struct *vma,
272 		unsigned long address, unsigned long end, pgprot_t newprot,
273 		unsigned long cp_flags);
274 void hugetlb_unshare_all_pmds(struct vm_area_struct *vma);
275 void fixup_hugetlb_reservations(struct vm_area_struct *vma);
276 void hugetlb_split(struct vm_area_struct *vma, unsigned long addr);
277 
278 unsigned int arch_hugetlb_cma_order(void);
279 
280 #else /* !CONFIG_HUGETLB_PAGE */
281 
282 static inline void hugetlb_dup_vma_private(struct vm_area_struct *vma)
283 {
284 }
285 
286 static inline void clear_vma_resv_huge_pages(struct vm_area_struct *vma)
287 {
288 }
289 
290 static inline unsigned long hugetlb_total_pages(void)
291 {
292 	return 0;
293 }
294 
295 static inline struct address_space *hugetlb_folio_mapping_lock_write(
296 							struct folio *folio)
297 {
298 	return NULL;
299 }
300 
301 static inline int huge_pmd_unshare(struct mmu_gather *tlb,
302 		struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
303 {
304 	return 0;
305 }
306 
307 static inline void huge_pmd_unshare_flush(struct mmu_gather *tlb,
308 		struct vm_area_struct *vma)
309 {
310 }
311 
312 static inline void adjust_range_if_pmd_sharing_possible(
313 				struct vm_area_struct *vma,
314 				unsigned long *start, unsigned long *end)
315 {
316 }
317 
318 static inline void hugetlb_zap_begin(
319 				struct vm_area_struct *vma,
320 				unsigned long *start, unsigned long *end)
321 {
322 }
323 
324 static inline void hugetlb_zap_end(
325 				struct vm_area_struct *vma,
326 				struct zap_details *details)
327 {
328 }
329 
330 static inline int copy_hugetlb_page_range(struct mm_struct *dst,
331 					  struct mm_struct *src,
332 					  struct vm_area_struct *dst_vma,
333 					  struct vm_area_struct *src_vma)
334 {
335 	BUG();
336 	return 0;
337 }
338 
339 static inline int move_hugetlb_page_tables(struct vm_area_struct *vma,
340 					   struct vm_area_struct *new_vma,
341 					   unsigned long old_addr,
342 					   unsigned long new_addr,
343 					   unsigned long len)
344 {
345 	BUG();
346 	return 0;
347 }
348 
349 static inline void hugetlb_report_meminfo(struct seq_file *m)
350 {
351 }
352 
353 static inline int hugetlb_report_node_meminfo(char *buf, int len, int nid)
354 {
355 	return 0;
356 }
357 
358 static inline void hugetlb_show_meminfo_node(int nid)
359 {
360 }
361 
362 static inline void hugetlb_vma_lock_read(struct vm_area_struct *vma)
363 {
364 }
365 
366 static inline void hugetlb_vma_unlock_read(struct vm_area_struct *vma)
367 {
368 }
369 
370 static inline void hugetlb_vma_lock_write(struct vm_area_struct *vma)
371 {
372 }
373 
374 static inline void hugetlb_vma_unlock_write(struct vm_area_struct *vma)
375 {
376 }
377 
378 static inline int hugetlb_vma_trylock_write(struct vm_area_struct *vma)
379 {
380 	return 1;
381 }
382 
383 static inline void hugetlb_vma_assert_locked(struct vm_area_struct *vma)
384 {
385 }
386 
387 static inline int is_hugepage_only_range(struct mm_struct *mm,
388 					unsigned long addr, unsigned long len)
389 {
390 	return 0;
391 }
392 
393 #ifdef CONFIG_USERFAULTFD
394 static inline int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
395 					   struct vm_area_struct *dst_vma,
396 					   unsigned long dst_addr,
397 					   unsigned long src_addr,
398 					   uffd_flags_t flags,
399 					   struct folio **foliop)
400 {
401 	BUG();
402 	return 0;
403 }
404 #endif /* CONFIG_USERFAULTFD */
405 
406 static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
407 					unsigned long sz)
408 {
409 	return NULL;
410 }
411 
412 static inline bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list)
413 {
414 	return false;
415 }
416 
417 static inline int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
418 {
419 	return 0;
420 }
421 
422 static inline void folio_putback_hugetlb(struct folio *folio)
423 {
424 }
425 
426 static inline void move_hugetlb_state(struct folio *old_folio,
427 					struct folio *new_folio, int reason)
428 {
429 }
430 
431 static inline long hugetlb_change_protection(
432 			struct vm_area_struct *vma, unsigned long address,
433 			unsigned long end, pgprot_t newprot,
434 			unsigned long cp_flags)
435 {
436 	return 0;
437 }
438 
439 static inline void __unmap_hugepage_range(struct mmu_gather *tlb,
440 			struct vm_area_struct *vma, unsigned long start,
441 			unsigned long end, struct folio *folio,
442 			zap_flags_t zap_flags)
443 {
444 	BUG();
445 }
446 
447 static inline vm_fault_t hugetlb_fault(struct mm_struct *mm,
448 			struct vm_area_struct *vma, unsigned long address,
449 			unsigned int flags)
450 {
451 	BUG();
452 	return 0;
453 }
454 
455 static inline void hugetlb_unshare_all_pmds(struct vm_area_struct *vma) { }
456 
457 static inline void fixup_hugetlb_reservations(struct vm_area_struct *vma)
458 {
459 }
460 
461 static inline void hugetlb_split(struct vm_area_struct *vma, unsigned long addr) {}
462 
463 #endif /* !CONFIG_HUGETLB_PAGE */
464 
465 #ifndef pgd_write
466 static inline int pgd_write(pgd_t pgd)
467 {
468 	BUG();
469 	return 0;
470 }
471 #endif
472 
473 #define HUGETLB_ANON_FILE "anon_hugepage"
474 
475 enum {
476 	/*
477 	 * The file will be used as an shm file so shmfs accounting rules
478 	 * apply
479 	 */
480 	HUGETLB_SHMFS_INODE     = 1,
481 	/*
482 	 * The file is being created on the internal vfs mount and shmfs
483 	 * accounting rules do not apply
484 	 */
485 	HUGETLB_ANONHUGE_INODE  = 2,
486 };
487 
488 #ifdef CONFIG_HUGETLBFS
489 struct hugetlbfs_sb_info {
490 	long	max_inodes;   /* inodes allowed */
491 	long	free_inodes;  /* inodes free */
492 	spinlock_t	stat_lock;
493 	struct hstate *hstate;
494 	struct hugepage_subpool *spool;
495 	kuid_t	uid;
496 	kgid_t	gid;
497 	umode_t mode;
498 };
499 
500 static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
501 {
502 	return sb->s_fs_info;
503 }
504 
505 struct hugetlbfs_inode_info {
506 	struct inode vfs_inode;
507 	struct resv_map *resv_map;
508 	unsigned int seals;
509 };
510 
511 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
512 {
513 	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
514 }
515 
516 extern const struct vm_operations_struct hugetlb_vm_ops;
517 struct file *hugetlb_file_setup(const char *name, size_t size, vma_flags_t acct,
518 				int creat_flags, int page_size_log);
519 
520 static inline bool is_file_hugepages(const struct file *file)
521 {
522 	return file->f_op->fop_flags & FOP_HUGE_PAGES;
523 }
524 
525 static inline struct hstate *hstate_inode(struct inode *i)
526 {
527 	return HUGETLBFS_SB(i->i_sb)->hstate;
528 }
529 #else /* !CONFIG_HUGETLBFS */
530 
531 #define is_file_hugepages(file)			false
532 static inline struct file *
533 hugetlb_file_setup(const char *name, size_t size, vma_flags_t acctflag,
534 		int creat_flags, int page_size_log)
535 {
536 	return ERR_PTR(-ENOSYS);
537 }
538 
539 static inline struct hstate *hstate_inode(struct inode *i)
540 {
541 	return NULL;
542 }
543 #endif /* !CONFIG_HUGETLBFS */
544 
545 unsigned long
546 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
547 				    unsigned long len, unsigned long pgoff,
548 				    unsigned long flags);
549 
550 /*
551  * huegtlb page specific state flags.  These flags are located in page.private
552  * of the hugetlb head page.  Functions created via the below macros should be
553  * used to manipulate these flags.
554  *
555  * HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
556  *	allocation time.  Cleared when page is fully instantiated.  Free
557  *	routine checks flag to restore a reservation on error paths.
558  *	Synchronization:  Examined or modified by code that knows it has
559  *	the only reference to page.  i.e. After allocation but before use
560  *	or when the page is being freed.
561  * HPG_migratable  - Set after a newly allocated page is added to the page
562  *	cache and/or page tables.  Indicates the page is a candidate for
563  *	migration.
564  *	Synchronization:  Initially set after new page allocation with no
565  *	locking.  When examined and modified during migration processing
566  *	(isolate, migrate, putback) the hugetlb_lock is held.
567  * HPG_temporary - Set on a page that is temporarily allocated from the buddy
568  *	allocator.  Typically used for migration target pages when no pages
569  *	are available in the pool.  The hugetlb free page path will
570  *	immediately free pages with this flag set to the buddy allocator.
571  *	Synchronization: Can be set after huge page allocation from buddy when
572  *	code knows it has only reference.  All other examinations and
573  *	modifications require hugetlb_lock.
574  * HPG_freed - Set when page is on the free lists.
575  *	Synchronization: hugetlb_lock held for examination and modification.
576  * HPG_vmemmap_optimized - Set when the vmemmap pages of the page are freed.
577  * HPG_raw_hwp_unreliable - Set when the hugetlb page has a hwpoison sub-page
578  *     that is not tracked by raw_hwp_page list.
579  */
580 enum hugetlb_page_flags {
581 	HPG_restore_reserve = 0,
582 	HPG_migratable,
583 	HPG_temporary,
584 	HPG_freed,
585 	HPG_vmemmap_optimized,
586 	HPG_raw_hwp_unreliable,
587 	HPG_cma,
588 	__NR_HPAGEFLAGS,
589 };
590 
591 /*
592  * Macros to create test, set and clear function definitions for
593  * hugetlb specific page flags.
594  */
595 #ifdef CONFIG_HUGETLB_PAGE
596 #define TESTHPAGEFLAG(uname, flname)				\
597 static __always_inline						\
598 bool folio_test_hugetlb_##flname(struct folio *folio)		\
599 	{	void *private = &folio->private;		\
600 		return test_bit(HPG_##flname, private);		\
601 	}
602 
603 #define SETHPAGEFLAG(uname, flname)				\
604 static __always_inline						\
605 void folio_set_hugetlb_##flname(struct folio *folio)		\
606 	{	void *private = &folio->private;		\
607 		set_bit(HPG_##flname, private);			\
608 	}
609 
610 #define CLEARHPAGEFLAG(uname, flname)				\
611 static __always_inline						\
612 void folio_clear_hugetlb_##flname(struct folio *folio)		\
613 	{	void *private = &folio->private;		\
614 		clear_bit(HPG_##flname, private);		\
615 	}
616 #else
617 #define TESTHPAGEFLAG(uname, flname)				\
618 static inline bool						\
619 folio_test_hugetlb_##flname(struct folio *folio)		\
620 	{ return 0; }
621 
622 #define SETHPAGEFLAG(uname, flname)				\
623 static inline void						\
624 folio_set_hugetlb_##flname(struct folio *folio) 		\
625 	{ }
626 
627 #define CLEARHPAGEFLAG(uname, flname)				\
628 static inline void						\
629 folio_clear_hugetlb_##flname(struct folio *folio)		\
630 	{ }
631 #endif
632 
633 #define HPAGEFLAG(uname, flname)				\
634 	TESTHPAGEFLAG(uname, flname)				\
635 	SETHPAGEFLAG(uname, flname)				\
636 	CLEARHPAGEFLAG(uname, flname)				\
637 
638 /*
639  * Create functions associated with hugetlb page flags
640  */
641 HPAGEFLAG(RestoreReserve, restore_reserve)
642 HPAGEFLAG(Migratable, migratable)
643 HPAGEFLAG(Temporary, temporary)
644 HPAGEFLAG(Freed, freed)
645 HPAGEFLAG(VmemmapOptimized, vmemmap_optimized)
646 HPAGEFLAG(RawHwpUnreliable, raw_hwp_unreliable)
647 HPAGEFLAG(Cma, cma)
648 
649 #ifdef CONFIG_HUGETLB_PAGE
650 
651 #define HSTATE_NAME_LEN 32
652 /* Defines one hugetlb page size */
653 struct hstate {
654 	struct mutex resize_lock;
655 	struct lock_class_key resize_key;
656 	int next_nid_to_alloc;
657 	int next_nid_to_free;
658 	unsigned int order;
659 	unsigned int demote_order;
660 	unsigned long mask;
661 	unsigned long max_huge_pages;
662 	unsigned long nr_huge_pages;
663 	unsigned long free_huge_pages;
664 	unsigned long resv_huge_pages;
665 	unsigned long surplus_huge_pages;
666 	unsigned long nr_overcommit_huge_pages;
667 	struct list_head hugepage_activelist;
668 	struct list_head hugepage_freelists[MAX_NUMNODES];
669 	unsigned int max_huge_pages_node[MAX_NUMNODES];
670 	unsigned int nr_huge_pages_node[MAX_NUMNODES];
671 	unsigned int free_huge_pages_node[MAX_NUMNODES];
672 	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
673 	char name[HSTATE_NAME_LEN];
674 };
675 
676 struct cma;
677 
678 struct huge_bootmem_page {
679 	struct list_head list;
680 	struct hstate *hstate;
681 	unsigned long flags;
682 	struct cma *cma;
683 };
684 
685 #define HUGE_BOOTMEM_HVO		0x0001
686 #define HUGE_BOOTMEM_ZONES_VALID	0x0002
687 #define HUGE_BOOTMEM_CMA		0x0004
688 
689 bool hugetlb_bootmem_page_zones_valid(int nid, struct huge_bootmem_page *m);
690 
691 int isolate_or_dissolve_huge_folio(struct folio *folio, struct list_head *list);
692 int replace_free_hugepage_folios(unsigned long start_pfn, unsigned long end_pfn);
693 void wait_for_freed_hugetlb_folios(void);
694 struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
695 				unsigned long addr, bool cow_from_owner);
696 struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
697 				nodemask_t *nmask, gfp_t gfp_mask,
698 				bool allow_alloc_fallback);
699 struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
700 					  nodemask_t *nmask, gfp_t gfp_mask);
701 
702 int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,
703 			pgoff_t idx);
704 void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
705 				unsigned long address, struct folio *folio);
706 
707 /* arch callback */
708 int __init __alloc_bootmem_huge_page(struct hstate *h, int nid);
709 int __init alloc_bootmem_huge_page(struct hstate *h, int nid);
710 bool __init hugetlb_node_alloc_supported(void);
711 
712 void __init hugetlb_add_hstate(unsigned order);
713 bool __init arch_hugetlb_valid_size(unsigned long size);
714 struct hstate *size_to_hstate(unsigned long size);
715 
716 #ifndef HUGE_MAX_HSTATE
717 #define HUGE_MAX_HSTATE 1
718 #endif
719 
720 extern struct hstate hstates[HUGE_MAX_HSTATE];
721 extern unsigned int default_hstate_idx;
722 
723 #define default_hstate (hstates[default_hstate_idx])
724 
725 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
726 {
727 	return HUGETLBFS_SB(inode->i_sb)->spool;
728 }
729 
730 static inline struct hugepage_subpool *hugetlb_folio_subpool(struct folio *folio)
731 {
732 	return folio->_hugetlb_subpool;
733 }
734 
735 static inline void hugetlb_set_folio_subpool(struct folio *folio,
736 					struct hugepage_subpool *subpool)
737 {
738 	folio->_hugetlb_subpool = subpool;
739 }
740 
741 static inline struct hstate *hstate_file(struct file *f)
742 {
743 	return hstate_inode(file_inode(f));
744 }
745 
746 static inline struct hstate *hstate_sizelog(int page_size_log)
747 {
748 	if (!page_size_log)
749 		return &default_hstate;
750 
751 	if (page_size_log < BITS_PER_LONG)
752 		return size_to_hstate(1UL << page_size_log);
753 
754 	return NULL;
755 }
756 
757 static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
758 {
759 	return hstate_file(vma->vm_file);
760 }
761 
762 static inline unsigned long huge_page_size(const struct hstate *h)
763 {
764 	return (unsigned long)PAGE_SIZE << h->order;
765 }
766 
767 static inline unsigned long huge_page_mask(struct hstate *h)
768 {
769 	return h->mask;
770 }
771 
772 static inline unsigned int huge_page_order(struct hstate *h)
773 {
774 	return h->order;
775 }
776 
777 static inline unsigned huge_page_shift(struct hstate *h)
778 {
779 	return h->order + PAGE_SHIFT;
780 }
781 
782 /**
783  * hugetlb_linear_page_index() - linear_page_index() but in hugetlb
784  *				 page size granularity.
785  * @vma: the hugetlb VMA
786  * @address: the virtual address within the VMA
787  *
788  * Return: the page offset within the mapping in huge page units.
789  */
790 static inline pgoff_t hugetlb_linear_page_index(struct vm_area_struct *vma,
791 		unsigned long address)
792 {
793 	struct hstate *h = hstate_vma(vma);
794 
795 	return ((address - vma->vm_start) >> huge_page_shift(h)) +
796 		(vma->vm_pgoff >> huge_page_order(h));
797 }
798 
799 static inline bool order_is_gigantic(unsigned int order)
800 {
801 	return order > MAX_PAGE_ORDER;
802 }
803 
804 static inline bool hstate_is_gigantic(struct hstate *h)
805 {
806 	return order_is_gigantic(huge_page_order(h));
807 }
808 
809 static inline unsigned int pages_per_huge_page(const struct hstate *h)
810 {
811 	return 1 << h->order;
812 }
813 
814 static inline unsigned int blocks_per_huge_page(struct hstate *h)
815 {
816 	return huge_page_size(h) / 512;
817 }
818 
819 static inline struct folio *filemap_lock_hugetlb_folio(struct hstate *h,
820 				struct address_space *mapping, pgoff_t idx)
821 {
822 	return filemap_lock_folio(mapping, idx << huge_page_order(h));
823 }
824 
825 #include <asm/hugetlb.h>
826 
827 #ifndef is_hugepage_only_range
828 static inline int is_hugepage_only_range(struct mm_struct *mm,
829 					unsigned long addr, unsigned long len)
830 {
831 	return 0;
832 }
833 #define is_hugepage_only_range is_hugepage_only_range
834 #endif
835 
836 #ifndef arch_clear_hugetlb_flags
837 static inline void arch_clear_hugetlb_flags(struct folio *folio) { }
838 #define arch_clear_hugetlb_flags arch_clear_hugetlb_flags
839 #endif
840 
841 #ifndef arch_make_huge_pte
842 static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
843 				       vm_flags_t flags)
844 {
845 	return pte_mkhuge(entry);
846 }
847 #endif
848 
849 #ifndef arch_has_huge_bootmem_alloc
850 /*
851  * Some architectures do their own bootmem allocation, so they can't use
852  * early CMA allocation.
853  */
854 static inline bool arch_has_huge_bootmem_alloc(void)
855 {
856 	return false;
857 }
858 #endif
859 
860 static inline struct hstate *folio_hstate(struct folio *folio)
861 {
862 	VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
863 	return size_to_hstate(folio_size(folio));
864 }
865 
866 static inline unsigned hstate_index_to_shift(unsigned index)
867 {
868 	return hstates[index].order + PAGE_SHIFT;
869 }
870 
871 static inline int hstate_index(struct hstate *h)
872 {
873 	return h - hstates;
874 }
875 
876 int dissolve_free_hugetlb_folio(struct folio *folio);
877 int dissolve_free_hugetlb_folios(unsigned long start_pfn,
878 				    unsigned long end_pfn);
879 
880 #ifdef CONFIG_MEMORY_FAILURE
881 extern void folio_clear_hugetlb_hwpoison(struct folio *folio);
882 #else
883 static inline void folio_clear_hugetlb_hwpoison(struct folio *folio)
884 {
885 }
886 #endif
887 
888 #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
889 #ifndef arch_hugetlb_migration_supported
890 static inline bool arch_hugetlb_migration_supported(struct hstate *h)
891 {
892 	if ((huge_page_shift(h) == PMD_SHIFT) ||
893 		(huge_page_shift(h) == PUD_SHIFT) ||
894 			(huge_page_shift(h) == PGDIR_SHIFT))
895 		return true;
896 	else
897 		return false;
898 }
899 #endif
900 #else
901 static inline bool arch_hugetlb_migration_supported(struct hstate *h)
902 {
903 	return false;
904 }
905 #endif
906 
907 static inline bool hugepage_migration_supported(struct hstate *h)
908 {
909 	return arch_hugetlb_migration_supported(h);
910 }
911 
912 /*
913  * Movability check is different as compared to migration check.
914  * It determines whether or not a huge page should be placed on
915  * movable zone or not. Movability of any huge page should be
916  * required only if huge page size is supported for migration.
917  * There won't be any reason for the huge page to be movable if
918  * it is not migratable to start with. Also the size of the huge
919  * page should be large enough to be placed under a movable zone
920  * and still feasible enough to be migratable. Just the presence
921  * in movable zone does not make the migration feasible.
922  *
923  * So even though large huge page sizes like the gigantic ones
924  * are migratable they should not be movable because its not
925  * feasible to migrate them from movable zone.
926  */
927 static inline bool hugepage_movable_supported(struct hstate *h)
928 {
929 	if (!hugepage_migration_supported(h))
930 		return false;
931 
932 	if (hstate_is_gigantic(h) && !movable_gigantic_pages)
933 		return false;
934 	return true;
935 }
936 
937 /* Movability of hugepages depends on migration support. */
938 static inline gfp_t htlb_alloc_mask(struct hstate *h)
939 {
940 	gfp_t gfp = __GFP_COMP | __GFP_NOWARN;
941 
942 	gfp |= hugepage_movable_supported(h) ? GFP_HIGHUSER_MOVABLE : GFP_HIGHUSER;
943 
944 	return gfp;
945 }
946 
947 static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
948 {
949 	gfp_t modified_mask = htlb_alloc_mask(h);
950 
951 	/* Some callers might want to enforce node */
952 	modified_mask |= (gfp_mask & __GFP_THISNODE);
953 
954 	modified_mask |= (gfp_mask & __GFP_NOWARN);
955 
956 	return modified_mask;
957 }
958 
959 static inline bool htlb_allow_alloc_fallback(int reason)
960 {
961 	bool allowed_fallback = false;
962 
963 	/*
964 	 * Note: the memory offline, memory failure and migration syscalls will
965 	 * be allowed to fallback to other nodes due to lack of a better chioce,
966 	 * that might break the per-node hugetlb pool. While other cases will
967 	 * set the __GFP_THISNODE to avoid breaking the per-node hugetlb pool.
968 	 */
969 	switch (reason) {
970 	case MR_MEMORY_HOTPLUG:
971 	case MR_MEMORY_FAILURE:
972 	case MR_SYSCALL:
973 	case MR_MEMPOLICY_MBIND:
974 		allowed_fallback = true;
975 		break;
976 	default:
977 		break;
978 	}
979 
980 	return allowed_fallback;
981 }
982 
983 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
984 					   struct mm_struct *mm, pte_t *pte)
985 {
986 	const unsigned long size = huge_page_size(h);
987 
988 	VM_WARN_ON(size == PAGE_SIZE);
989 
990 	/*
991 	 * hugetlb must use the exact same PT locks as core-mm page table
992 	 * walkers would. When modifying a PTE table, hugetlb must take the
993 	 * PTE PT lock, when modifying a PMD table, hugetlb must take the PMD
994 	 * PT lock etc.
995 	 *
996 	 * The expectation is that any hugetlb folio smaller than a PMD is
997 	 * always mapped into a single PTE table and that any hugetlb folio
998 	 * smaller than a PUD (but at least as big as a PMD) is always mapped
999 	 * into a single PMD table.
1000 	 *
1001 	 * If that does not hold for an architecture, then that architecture
1002 	 * must disable split PT locks such that all *_lockptr() functions
1003 	 * will give us the same result: the per-MM PT lock.
1004 	 *
1005 	 * Note that with e.g., CONFIG_PGTABLE_LEVELS=2 where
1006 	 * PGDIR_SIZE==P4D_SIZE==PUD_SIZE==PMD_SIZE, we'd use pud_lockptr()
1007 	 * and core-mm would use pmd_lockptr(). However, in such configurations
1008 	 * split PMD locks are disabled -- they don't make sense on a single
1009 	 * PGDIR page table -- and the end result is the same.
1010 	 */
1011 	if (size >= PUD_SIZE)
1012 		return pud_lockptr(mm, (pud_t *) pte);
1013 	else if (size >= PMD_SIZE || IS_ENABLED(CONFIG_HIGHPTE))
1014 		return pmd_lockptr(mm, (pmd_t *) pte);
1015 	/* pte_alloc_huge() only applies with !CONFIG_HIGHPTE */
1016 	return ptep_lockptr(mm, pte);
1017 }
1018 
1019 #ifndef hugepages_supported
1020 /*
1021  * Some platform decide whether they support huge pages at boot
1022  * time. Some of them, such as powerpc, set HPAGE_SHIFT to 0
1023  * when there is no such support
1024  */
1025 #define hugepages_supported() (HPAGE_SHIFT != 0)
1026 #endif
1027 
1028 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
1029 
1030 static inline void hugetlb_count_init(struct mm_struct *mm)
1031 {
1032 	atomic_long_set(&mm->hugetlb_usage, 0);
1033 }
1034 
1035 static inline void hugetlb_count_add(long l, struct mm_struct *mm)
1036 {
1037 	atomic_long_add(l, &mm->hugetlb_usage);
1038 }
1039 
1040 static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
1041 {
1042 	atomic_long_sub(l, &mm->hugetlb_usage);
1043 }
1044 
1045 #ifndef huge_ptep_modify_prot_start
1046 #define huge_ptep_modify_prot_start huge_ptep_modify_prot_start
1047 static inline pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
1048 						unsigned long addr, pte_t *ptep)
1049 {
1050 	unsigned long psize = huge_page_size(hstate_vma(vma));
1051 
1052 	return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep, psize);
1053 }
1054 #endif
1055 
1056 #ifndef huge_ptep_modify_prot_commit
1057 #define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit
1058 static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
1059 						unsigned long addr, pte_t *ptep,
1060 						pte_t old_pte, pte_t pte)
1061 {
1062 	unsigned long psize = huge_page_size(hstate_vma(vma));
1063 
1064 	set_huge_pte_at(vma->vm_mm, addr, ptep, pte, psize);
1065 }
1066 #endif
1067 
1068 #ifdef CONFIG_NUMA
1069 void hugetlb_register_node(struct node *node);
1070 void hugetlb_unregister_node(struct node *node);
1071 #endif
1072 
1073 /*
1074  * Check if a given raw @page in a hugepage is HWPOISON.
1075  */
1076 bool is_raw_hwpoison_page_in_hugepage(struct page *page);
1077 
1078 static inline unsigned long huge_page_mask_align(struct file *file)
1079 {
1080 	return PAGE_MASK & ~huge_page_mask(hstate_file(file));
1081 }
1082 
1083 #else	/* CONFIG_HUGETLB_PAGE */
1084 struct hstate {};
1085 
1086 static inline unsigned long huge_page_mask_align(struct file *file)
1087 {
1088 	return 0;
1089 }
1090 
1091 static inline struct hugepage_subpool *hugetlb_folio_subpool(struct folio *folio)
1092 {
1093 	return NULL;
1094 }
1095 
1096 static inline struct folio *filemap_lock_hugetlb_folio(struct hstate *h,
1097 				struct address_space *mapping, pgoff_t idx)
1098 {
1099 	return NULL;
1100 }
1101 
1102 static inline int isolate_or_dissolve_huge_folio(struct folio *folio,
1103 						struct list_head *list)
1104 {
1105 	return -ENOMEM;
1106 }
1107 
1108 static inline int replace_free_hugepage_folios(unsigned long start_pfn,
1109 		unsigned long end_pfn)
1110 {
1111 	return 0;
1112 }
1113 
1114 static inline void wait_for_freed_hugetlb_folios(void)
1115 {
1116 }
1117 
1118 static inline struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
1119 					   unsigned long addr,
1120 					   bool cow_from_owner)
1121 {
1122 	return NULL;
1123 }
1124 
1125 static inline struct folio *
1126 alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
1127 			    nodemask_t *nmask, gfp_t gfp_mask)
1128 {
1129 	return NULL;
1130 }
1131 
1132 static inline struct folio *
1133 alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
1134 			nodemask_t *nmask, gfp_t gfp_mask,
1135 			bool allow_alloc_fallback)
1136 {
1137 	return NULL;
1138 }
1139 
1140 static inline int __alloc_bootmem_huge_page(struct hstate *h)
1141 {
1142 	return 0;
1143 }
1144 
1145 static inline struct hstate *hstate_file(struct file *f)
1146 {
1147 	return NULL;
1148 }
1149 
1150 static inline struct hstate *hstate_sizelog(int page_size_log)
1151 {
1152 	return NULL;
1153 }
1154 
1155 static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
1156 {
1157 	return NULL;
1158 }
1159 
1160 static inline struct hstate *folio_hstate(struct folio *folio)
1161 {
1162 	return NULL;
1163 }
1164 
1165 static inline struct hstate *size_to_hstate(unsigned long size)
1166 {
1167 	return NULL;
1168 }
1169 
1170 static inline unsigned long huge_page_size(struct hstate *h)
1171 {
1172 	return PAGE_SIZE;
1173 }
1174 
1175 static inline unsigned long huge_page_mask(struct hstate *h)
1176 {
1177 	return PAGE_MASK;
1178 }
1179 
1180 static inline unsigned int huge_page_order(struct hstate *h)
1181 {
1182 	return 0;
1183 }
1184 
1185 static inline unsigned int huge_page_shift(struct hstate *h)
1186 {
1187 	return PAGE_SHIFT;
1188 }
1189 
1190 static inline bool hstate_is_gigantic(struct hstate *h)
1191 {
1192 	return false;
1193 }
1194 
1195 static inline unsigned int pages_per_huge_page(struct hstate *h)
1196 {
1197 	return 1;
1198 }
1199 
1200 static inline unsigned hstate_index_to_shift(unsigned index)
1201 {
1202 	return 0;
1203 }
1204 
1205 static inline int hstate_index(struct hstate *h)
1206 {
1207 	return 0;
1208 }
1209 
1210 static inline int dissolve_free_hugetlb_folio(struct folio *folio)
1211 {
1212 	return 0;
1213 }
1214 
1215 static inline int dissolve_free_hugetlb_folios(unsigned long start_pfn,
1216 					   unsigned long end_pfn)
1217 {
1218 	return 0;
1219 }
1220 
1221 static inline bool hugepage_migration_supported(struct hstate *h)
1222 {
1223 	return false;
1224 }
1225 
1226 static inline bool hugepage_movable_supported(struct hstate *h)
1227 {
1228 	return false;
1229 }
1230 
1231 static inline gfp_t htlb_alloc_mask(struct hstate *h)
1232 {
1233 	return 0;
1234 }
1235 
1236 static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
1237 {
1238 	return 0;
1239 }
1240 
1241 static inline bool htlb_allow_alloc_fallback(int reason)
1242 {
1243 	return false;
1244 }
1245 
1246 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
1247 					   struct mm_struct *mm, pte_t *pte)
1248 {
1249 	return &mm->page_table_lock;
1250 }
1251 
1252 static inline void hugetlb_count_init(struct mm_struct *mm)
1253 {
1254 }
1255 
1256 static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
1257 {
1258 }
1259 
1260 static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
1261 {
1262 }
1263 
1264 static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
1265 					  unsigned long addr, pte_t *ptep)
1266 {
1267 #ifdef CONFIG_MMU
1268 	return ptep_get(ptep);
1269 #else
1270 	return *ptep;
1271 #endif
1272 }
1273 
1274 static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
1275 				   pte_t *ptep, pte_t pte, unsigned long sz)
1276 {
1277 }
1278 
1279 static inline void hugetlb_register_node(struct node *node)
1280 {
1281 }
1282 
1283 static inline void hugetlb_unregister_node(struct node *node)
1284 {
1285 }
1286 
1287 static inline bool hugetlbfs_pagecache_present(
1288     struct hstate *h, struct vm_area_struct *vma, unsigned long address)
1289 {
1290 	return false;
1291 }
1292 
1293 static inline void hugetlb_bootmem_alloc(void)
1294 {
1295 }
1296 #endif	/* CONFIG_HUGETLB_PAGE */
1297 
1298 static inline spinlock_t *huge_pte_lock(struct hstate *h,
1299 					struct mm_struct *mm, pte_t *pte)
1300 {
1301 	spinlock_t *ptl;
1302 
1303 	ptl = huge_pte_lockptr(h, mm, pte);
1304 	spin_lock(ptl);
1305 	return ptl;
1306 }
1307 
1308 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
1309 extern void __init hugetlb_cma_reserve(void);
1310 #else
1311 static inline __init void hugetlb_cma_reserve(void)
1312 {
1313 }
1314 #endif
1315 
1316 #ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
1317 static inline bool hugetlb_pmd_shared(pte_t *pte)
1318 {
1319 	return ptdesc_pmd_is_shared(virt_to_ptdesc(pte));
1320 }
1321 #else
1322 static inline bool hugetlb_pmd_shared(pte_t *pte)
1323 {
1324 	return false;
1325 }
1326 #endif
1327 
1328 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr);
1329 
1330 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
1331 /*
1332  * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
1333  * implement this.
1334  */
1335 #define flush_hugetlb_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
1336 #endif
1337 
1338 static inline bool __vma_shareable_lock(struct vm_area_struct *vma)
1339 {
1340 	return (vma->vm_flags & VM_MAYSHARE) && vma->vm_private_data;
1341 }
1342 
1343 bool __vma_private_lock(struct vm_area_struct *vma);
1344 
1345 /*
1346  * Safe version of huge_pte_offset() to check the locks.  See comments
1347  * above huge_pte_offset().
1348  */
1349 static inline pte_t *
1350 hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long sz)
1351 {
1352 #if defined(CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING) && defined(CONFIG_LOCKDEP)
1353 	struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
1354 
1355 	/*
1356 	 * If pmd sharing possible, locking needed to safely walk the
1357 	 * hugetlb pgtables.  More information can be found at the comment
1358 	 * above huge_pte_offset() in the same file.
1359 	 *
1360 	 * NOTE: lockdep_is_held() is only defined with CONFIG_LOCKDEP.
1361 	 */
1362 	if (__vma_shareable_lock(vma))
1363 		WARN_ON_ONCE(!lockdep_is_held(&vma_lock->rw_sema) &&
1364 			     !lockdep_is_held(
1365 				 &vma->vm_file->f_mapping->i_mmap_rwsem));
1366 #endif
1367 	return huge_pte_offset(vma->vm_mm, addr, sz);
1368 }
1369 
1370 #endif /* _LINUX_HUGETLB_H */
1371