Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef _LINUX_MM_TYPES_H
3 : #define _LINUX_MM_TYPES_H
4 :
5 : #include <linux/mm_types_task.h>
6 :
7 : #include <linux/auxvec.h>
8 : #include <linux/kref.h>
9 : #include <linux/list.h>
10 : #include <linux/spinlock.h>
11 : #include <linux/rbtree.h>
12 : #include <linux/maple_tree.h>
13 : #include <linux/rwsem.h>
14 : #include <linux/completion.h>
15 : #include <linux/cpumask.h>
16 : #include <linux/uprobes.h>
17 : #include <linux/rcupdate.h>
18 : #include <linux/page-flags-layout.h>
19 : #include <linux/workqueue.h>
20 : #include <linux/seqlock.h>
21 : #include <linux/percpu_counter.h>
22 :
23 : #include <asm/mmu.h>
24 :
25 : #ifndef AT_VECTOR_SIZE_ARCH
26 : #define AT_VECTOR_SIZE_ARCH 0
27 : #endif
28 : #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
29 :
30 : #define INIT_PASID 0
31 :
32 : struct address_space;
33 : struct mem_cgroup;
34 :
35 : /*
36 : * Each physical page in the system has a struct page associated with
37 : * it to keep track of whatever it is we are using the page for at the
38 : * moment. Note that we have no way to track which tasks are using
39 : * a page, though if it is a pagecache page, rmap structures can tell us
40 : * who is mapping it.
41 : *
42 : * If you allocate the page using alloc_pages(), you can use some of the
43 : * space in struct page for your own purposes. The five words in the main
44 : * union are available, except for bit 0 of the first word which must be
45 : * kept clear. Many users use this word to store a pointer to an object
46 : * which is guaranteed to be aligned. If you use the same storage as
47 : * page->mapping, you must restore it to NULL before freeing the page.
48 : *
49 : * If your page will not be mapped to userspace, you can also use the four
50 : * bytes in the mapcount union, but you must call page_mapcount_reset()
51 : * before freeing it.
52 : *
53 : * If you want to use the refcount field, it must be used in such a way
54 : * that other CPUs temporarily incrementing and then decrementing the
55 : * refcount does not cause problems. On receiving the page from
56 : * alloc_pages(), the refcount will be positive.
57 : *
58 : * If you allocate pages of order > 0, you can use some of the fields
59 : * in each subpage, but you may need to restore some of their values
60 : * afterwards.
61 : *
62 : * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
63 : * That requires that freelist & counters in struct slab be adjacent and
64 : * double-word aligned. Because struct slab currently just reinterprets the
65 : * bits of struct page, we align all struct pages to double-word boundaries,
66 : * and ensure that 'freelist' is aligned within struct slab.
67 : */
68 : #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
69 : #define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
70 : #else
71 : #define _struct_page_alignment __aligned(sizeof(unsigned long))
72 : #endif
73 :
74 : struct page {
75 : unsigned long flags; /* Atomic flags, some possibly
76 : * updated asynchronously */
77 : /*
78 : * Five words (20/40 bytes) are available in this union.
79 : * WARNING: bit 0 of the first word is used for PageTail(). That
80 : * means the other users of this union MUST NOT use the bit to
81 : * avoid collision and false-positive PageTail().
82 : */
83 : union {
84 : struct { /* Page cache and anonymous pages */
85 : /**
86 : * @lru: Pageout list, eg. active_list protected by
87 : * lruvec->lru_lock. Sometimes used as a generic list
88 : * by the page owner.
89 : */
90 : union {
91 : struct list_head lru;
92 :
93 : /* Or, for the Unevictable "LRU list" slot */
94 : struct {
95 : /* Always even, to negate PageTail */
96 : void *__filler;
97 : /* Count page's or folio's mlocks */
98 : unsigned int mlock_count;
99 : };
100 :
101 : /* Or, free page */
102 : struct list_head buddy_list;
103 : struct list_head pcp_list;
104 : };
105 : /* See page-flags.h for PAGE_MAPPING_FLAGS */
106 : struct address_space *mapping;
107 : union {
108 : pgoff_t index; /* Our offset within mapping. */
109 : unsigned long share; /* share count for fsdax */
110 : };
111 : /**
112 : * @private: Mapping-private opaque data.
113 : * Usually used for buffer_heads if PagePrivate.
114 : * Used for swp_entry_t if PageSwapCache.
115 : * Indicates order in the buddy system if PageBuddy.
116 : */
117 : unsigned long private;
118 : };
119 : struct { /* page_pool used by netstack */
120 : /**
121 : * @pp_magic: magic value to avoid recycling non
122 : * page_pool allocated pages.
123 : */
124 : unsigned long pp_magic;
125 : struct page_pool *pp;
126 : unsigned long _pp_mapping_pad;
127 : unsigned long dma_addr;
128 : union {
129 : /**
130 : * dma_addr_upper: might require a 64-bit
131 : * value on 32-bit architectures.
132 : */
133 : unsigned long dma_addr_upper;
134 : /**
135 : * For frag page support, not supported in
136 : * 32-bit architectures with 64-bit DMA.
137 : */
138 : atomic_long_t pp_frag_count;
139 : };
140 : };
141 : struct { /* Tail pages of compound page */
142 : unsigned long compound_head; /* Bit zero is set */
143 : };
144 : struct { /* Page table pages */
145 : unsigned long _pt_pad_1; /* compound_head */
146 : pgtable_t pmd_huge_pte; /* protected by page->ptl */
147 : unsigned long _pt_pad_2; /* mapping */
148 : union {
149 : struct mm_struct *pt_mm; /* x86 pgds only */
150 : atomic_t pt_frag_refcount; /* powerpc */
151 : };
152 : #if ALLOC_SPLIT_PTLOCKS
153 : spinlock_t *ptl;
154 : #else
155 : spinlock_t ptl;
156 : #endif
157 : };
158 : struct { /* ZONE_DEVICE pages */
159 : /** @pgmap: Points to the hosting device page map. */
160 : struct dev_pagemap *pgmap;
161 : void *zone_device_data;
162 : /*
163 : * ZONE_DEVICE private pages are counted as being
164 : * mapped so the next 3 words hold the mapping, index,
165 : * and private fields from the source anonymous or
166 : * page cache page while the page is migrated to device
167 : * private memory.
168 : * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
169 : * use the mapping, index, and private fields when
170 : * pmem backed DAX files are mapped.
171 : */
172 : };
173 :
174 : /** @rcu_head: You can use this to free a page by RCU. */
175 : struct rcu_head rcu_head;
176 : };
177 :
178 : union { /* This union is 4 bytes in size. */
179 : /*
180 : * If the page can be mapped to userspace, encodes the number
181 : * of times this page is referenced by a page table.
182 : */
183 : atomic_t _mapcount;
184 :
185 : /*
186 : * If the page is neither PageSlab nor mappable to userspace,
187 : * the value stored here may help determine what this page
188 : * is used for. See page-flags.h for a list of page types
189 : * which are currently stored here.
190 : */
191 : unsigned int page_type;
192 : };
193 :
194 : /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
195 : atomic_t _refcount;
196 :
197 : #ifdef CONFIG_MEMCG
198 : unsigned long memcg_data;
199 : #endif
200 :
201 : /*
202 : * On machines where all RAM is mapped into kernel address space,
203 : * we can simply calculate the virtual address. On machines with
204 : * highmem some memory is mapped into kernel virtual memory
205 : * dynamically, so we need a place to store that address.
206 : * Note that this field could be 16 bits on x86 ... ;)
207 : *
208 : * Architectures with slow multiplication can define
209 : * WANT_PAGE_VIRTUAL in asm/page.h
210 : */
211 : #if defined(WANT_PAGE_VIRTUAL)
212 : void *virtual; /* Kernel virtual address (NULL if
213 : not kmapped, ie. highmem) */
214 : #endif /* WANT_PAGE_VIRTUAL */
215 :
216 : #ifdef CONFIG_KMSAN
217 : /*
218 : * KMSAN metadata for this page:
219 : * - shadow page: every bit indicates whether the corresponding
220 : * bit of the original page is initialized (0) or not (1);
221 : * - origin page: every 4 bytes contain an id of the stack trace
222 : * where the uninitialized value was created.
223 : */
224 : struct page *kmsan_shadow;
225 : struct page *kmsan_origin;
226 : #endif
227 :
228 : #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
229 : int _last_cpupid;
230 : #endif
231 : } _struct_page_alignment;
232 :
233 : /*
234 : * struct encoded_page - a nonexistent type marking this pointer
235 : *
236 : * An 'encoded_page' pointer is a pointer to a regular 'struct page', but
237 : * with the low bits of the pointer indicating extra context-dependent
238 : * information. Not super-common, but happens in mmu_gather and mlock
239 : * handling, and this acts as a type system check on that use.
240 : *
241 : * We only really have two guaranteed bits in general, although you could
242 : * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
243 : * for more.
244 : *
245 : * Use the supplied helper functions to endcode/decode the pointer and bits.
246 : */
247 : struct encoded_page;
248 : #define ENCODE_PAGE_BITS 3ul
249 : static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
250 : {
251 : BUILD_BUG_ON(flags > ENCODE_PAGE_BITS);
252 : return (struct encoded_page *)(flags | (unsigned long)page);
253 : }
254 :
255 : static inline unsigned long encoded_page_flags(struct encoded_page *page)
256 : {
257 : return ENCODE_PAGE_BITS & (unsigned long)page;
258 : }
259 :
260 : static inline struct page *encoded_page_ptr(struct encoded_page *page)
261 : {
262 0 : return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page);
263 : }
264 :
265 : /**
266 : * struct folio - Represents a contiguous set of bytes.
267 : * @flags: Identical to the page flags.
268 : * @lru: Least Recently Used list; tracks how recently this folio was used.
269 : * @mlock_count: Number of times this folio has been pinned by mlock().
270 : * @mapping: The file this page belongs to, or refers to the anon_vma for
271 : * anonymous memory.
272 : * @index: Offset within the file, in units of pages. For anonymous memory,
273 : * this is the index from the beginning of the mmap.
274 : * @private: Filesystem per-folio data (see folio_attach_private()).
275 : * Used for swp_entry_t if folio_test_swapcache().
276 : * @_mapcount: Do not access this member directly. Use folio_mapcount() to
277 : * find out how many times this folio is mapped by userspace.
278 : * @_refcount: Do not access this member directly. Use folio_ref_count()
279 : * to find how many references there are to this folio.
280 : * @memcg_data: Memory Control Group data.
281 : * @_folio_dtor: Which destructor to use for this folio.
282 : * @_folio_order: Do not use directly, call folio_order().
283 : * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
284 : * @_nr_pages_mapped: Do not use directly, call folio_mapcount().
285 : * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
286 : * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
287 : * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
288 : * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
289 : * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
290 : * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
291 : * @_deferred_list: Folios to be split under memory pressure.
292 : *
293 : * A folio is a physically, virtually and logically contiguous set
294 : * of bytes. It is a power-of-two in size, and it is aligned to that
295 : * same power-of-two. It is at least as large as %PAGE_SIZE. If it is
296 : * in the page cache, it is at a file offset which is a multiple of that
297 : * power-of-two. It may be mapped into userspace at an address which is
298 : * at an arbitrary page offset, but its kernel virtual address is aligned
299 : * to its size.
300 : */
301 : struct folio {
302 : /* private: don't document the anon union */
303 : union {
304 : struct {
305 : /* public: */
306 : unsigned long flags;
307 : union {
308 : struct list_head lru;
309 : /* private: avoid cluttering the output */
310 : struct {
311 : void *__filler;
312 : /* public: */
313 : unsigned int mlock_count;
314 : /* private: */
315 : };
316 : /* public: */
317 : };
318 : struct address_space *mapping;
319 : pgoff_t index;
320 : void *private;
321 : atomic_t _mapcount;
322 : atomic_t _refcount;
323 : #ifdef CONFIG_MEMCG
324 : unsigned long memcg_data;
325 : #endif
326 : /* private: the union with struct page is transitional */
327 : };
328 : struct page page;
329 : };
330 : union {
331 : struct {
332 : unsigned long _flags_1;
333 : unsigned long _head_1;
334 : /* public: */
335 : unsigned char _folio_dtor;
336 : unsigned char _folio_order;
337 : atomic_t _entire_mapcount;
338 : atomic_t _nr_pages_mapped;
339 : atomic_t _pincount;
340 : #ifdef CONFIG_64BIT
341 : unsigned int _folio_nr_pages;
342 : #endif
343 : /* private: the union with struct page is transitional */
344 : };
345 : struct page __page_1;
346 : };
347 : union {
348 : struct {
349 : unsigned long _flags_2;
350 : unsigned long _head_2;
351 : /* public: */
352 : void *_hugetlb_subpool;
353 : void *_hugetlb_cgroup;
354 : void *_hugetlb_cgroup_rsvd;
355 : void *_hugetlb_hwpoison;
356 : /* private: the union with struct page is transitional */
357 : };
358 : struct {
359 : unsigned long _flags_2a;
360 : unsigned long _head_2a;
361 : /* public: */
362 : struct list_head _deferred_list;
363 : /* private: the union with struct page is transitional */
364 : };
365 : struct page __page_2;
366 : };
367 : };
368 :
369 : #define FOLIO_MATCH(pg, fl) \
370 : static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
371 : FOLIO_MATCH(flags, flags);
372 : FOLIO_MATCH(lru, lru);
373 : FOLIO_MATCH(mapping, mapping);
374 : FOLIO_MATCH(compound_head, lru);
375 : FOLIO_MATCH(index, index);
376 : FOLIO_MATCH(private, private);
377 : FOLIO_MATCH(_mapcount, _mapcount);
378 : FOLIO_MATCH(_refcount, _refcount);
379 : #ifdef CONFIG_MEMCG
380 : FOLIO_MATCH(memcg_data, memcg_data);
381 : #endif
382 : #undef FOLIO_MATCH
383 : #define FOLIO_MATCH(pg, fl) \
384 : static_assert(offsetof(struct folio, fl) == \
385 : offsetof(struct page, pg) + sizeof(struct page))
386 : FOLIO_MATCH(flags, _flags_1);
387 : FOLIO_MATCH(compound_head, _head_1);
388 : #undef FOLIO_MATCH
389 : #define FOLIO_MATCH(pg, fl) \
390 : static_assert(offsetof(struct folio, fl) == \
391 : offsetof(struct page, pg) + 2 * sizeof(struct page))
392 : FOLIO_MATCH(flags, _flags_2);
393 : FOLIO_MATCH(compound_head, _head_2);
394 : #undef FOLIO_MATCH
395 :
396 : /*
397 : * Used for sizing the vmemmap region on some architectures
398 : */
399 : #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
400 :
401 : #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
402 : #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
403 :
404 : /*
405 : * page_private can be used on tail pages. However, PagePrivate is only
406 : * checked by the VM on the head page. So page_private on the tail pages
407 : * should be used for data that's ancillary to the head page (eg attaching
408 : * buffer heads to tail pages after attaching buffer heads to the head page)
409 : */
410 : #define page_private(page) ((page)->private)
411 :
412 : static inline void set_page_private(struct page *page, unsigned long private)
413 : {
414 52003 : page->private = private;
415 : }
416 :
417 : static inline void *folio_get_private(struct folio *folio)
418 : {
419 : return folio->private;
420 : }
421 :
422 : struct page_frag_cache {
423 : void * va;
424 : #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
425 : __u16 offset;
426 : __u16 size;
427 : #else
428 : __u32 offset;
429 : #endif
430 : /* we maintain a pagecount bias, so that we dont dirty cache line
431 : * containing page->_refcount every time we allocate a fragment.
432 : */
433 : unsigned int pagecnt_bias;
434 : bool pfmemalloc;
435 : };
436 :
437 : typedef unsigned long vm_flags_t;
438 :
439 : /*
440 : * A region containing a mapping of a non-memory backed file under NOMMU
441 : * conditions. These are held in a global tree and are pinned by the VMAs that
442 : * map parts of them.
443 : */
444 : struct vm_region {
445 : struct rb_node vm_rb; /* link in global region tree */
446 : vm_flags_t vm_flags; /* VMA vm_flags */
447 : unsigned long vm_start; /* start address of region */
448 : unsigned long vm_end; /* region initialised to here */
449 : unsigned long vm_top; /* region allocated to here */
450 : unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
451 : struct file *vm_file; /* the backing file or NULL */
452 :
453 : int vm_usage; /* region usage count (access under nommu_region_sem) */
454 : bool vm_icache_flushed : 1; /* true if the icache has been flushed for
455 : * this region */
456 : };
457 :
458 : #ifdef CONFIG_USERFAULTFD
459 : #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
460 : struct vm_userfaultfd_ctx {
461 : struct userfaultfd_ctx *ctx;
462 : };
463 : #else /* CONFIG_USERFAULTFD */
464 : #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
465 : struct vm_userfaultfd_ctx {};
466 : #endif /* CONFIG_USERFAULTFD */
467 :
468 : struct anon_vma_name {
469 : struct kref kref;
470 : /* The name needs to be at the end because it is dynamically sized. */
471 : char name[];
472 : };
473 :
474 : /*
475 : * This struct describes a virtual memory area. There is one of these
476 : * per VM-area/task. A VM area is any part of the process virtual memory
477 : * space that has a special rule for the page-fault handlers (ie a shared
478 : * library, the executable area etc).
479 : */
480 : struct vm_area_struct {
481 : /* The first cache line has the info for VMA tree walking. */
482 :
483 : unsigned long vm_start; /* Our start address within vm_mm. */
484 : unsigned long vm_end; /* The first byte after our end address
485 : within vm_mm. */
486 :
487 : struct mm_struct *vm_mm; /* The address space we belong to. */
488 :
489 : /*
490 : * Access permissions of this VMA.
491 : * See vmf_insert_mixed_prot() for discussion.
492 : */
493 : pgprot_t vm_page_prot;
494 :
495 : /*
496 : * Flags, see mm.h.
497 : * To modify use vm_flags_{init|reset|set|clear|mod} functions.
498 : */
499 : union {
500 : const vm_flags_t vm_flags;
501 : vm_flags_t __private __vm_flags;
502 : };
503 :
504 : /*
505 : * For areas with an address space and backing store,
506 : * linkage into the address_space->i_mmap interval tree.
507 : *
508 : */
509 : struct {
510 : struct rb_node rb;
511 : unsigned long rb_subtree_last;
512 : } shared;
513 :
514 : /*
515 : * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
516 : * list, after a COW of one of the file pages. A MAP_SHARED vma
517 : * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
518 : * or brk vma (with NULL file) can only be in an anon_vma list.
519 : */
520 : struct list_head anon_vma_chain; /* Serialized by mmap_lock &
521 : * page_table_lock */
522 : struct anon_vma *anon_vma; /* Serialized by page_table_lock */
523 :
524 : /* Function pointers to deal with this struct. */
525 : const struct vm_operations_struct *vm_ops;
526 :
527 : /* Information about our backing store: */
528 : unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
529 : units */
530 : struct file * vm_file; /* File we map to (can be NULL). */
531 : void * vm_private_data; /* was vm_pte (shared mem) */
532 :
533 : #ifdef CONFIG_ANON_VMA_NAME
534 : /*
535 : * For private and shared anonymous mappings, a pointer to a null
536 : * terminated string containing the name given to the vma, or NULL if
537 : * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
538 : */
539 : struct anon_vma_name *anon_name;
540 : #endif
541 : #ifdef CONFIG_SWAP
542 : atomic_long_t swap_readahead_info;
543 : #endif
544 : #ifndef CONFIG_MMU
545 : struct vm_region *vm_region; /* NOMMU mapping region */
546 : #endif
547 : #ifdef CONFIG_NUMA
548 : struct mempolicy *vm_policy; /* NUMA policy for the VMA */
549 : #endif
550 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
551 : } __randomize_layout;
552 :
553 : struct kioctx_table;
554 : struct mm_struct {
555 : struct {
556 : struct maple_tree mm_mt;
557 : #ifdef CONFIG_MMU
558 : unsigned long (*get_unmapped_area) (struct file *filp,
559 : unsigned long addr, unsigned long len,
560 : unsigned long pgoff, unsigned long flags);
561 : #endif
562 : unsigned long mmap_base; /* base of mmap area */
563 : unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
564 : #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
565 : /* Base addresses for compatible mmap() */
566 : unsigned long mmap_compat_base;
567 : unsigned long mmap_compat_legacy_base;
568 : #endif
569 : unsigned long task_size; /* size of task vm space */
570 : pgd_t * pgd;
571 :
572 : #ifdef CONFIG_MEMBARRIER
573 : /**
574 : * @membarrier_state: Flags controlling membarrier behavior.
575 : *
576 : * This field is close to @pgd to hopefully fit in the same
577 : * cache-line, which needs to be touched by switch_mm().
578 : */
579 : atomic_t membarrier_state;
580 : #endif
581 :
582 : /**
583 : * @mm_users: The number of users including userspace.
584 : *
585 : * Use mmget()/mmget_not_zero()/mmput() to modify. When this
586 : * drops to 0 (i.e. when the task exits and there are no other
587 : * temporary reference holders), we also release a reference on
588 : * @mm_count (which may then free the &struct mm_struct if
589 : * @mm_count also drops to 0).
590 : */
591 : atomic_t mm_users;
592 :
593 : /**
594 : * @mm_count: The number of references to &struct mm_struct
595 : * (@mm_users count as 1).
596 : *
597 : * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
598 : * &struct mm_struct is freed.
599 : */
600 : atomic_t mm_count;
601 : #ifdef CONFIG_SCHED_MM_CID
602 : /**
603 : * @cid_lock: Protect cid bitmap updates vs lookups.
604 : *
605 : * Prevent situations where updates to the cid bitmap happen
606 : * concurrently with lookups. Those can lead to situations
607 : * where a lookup cannot find a free bit simply because it was
608 : * unlucky enough to load, non-atomically, bitmap words as they
609 : * were being concurrently updated by the updaters.
610 : */
611 : raw_spinlock_t cid_lock;
612 : #endif
613 : #ifdef CONFIG_MMU
614 : atomic_long_t pgtables_bytes; /* size of all page tables */
615 : #endif
616 : int map_count; /* number of VMAs */
617 :
618 : spinlock_t page_table_lock; /* Protects page tables and some
619 : * counters
620 : */
621 : /*
622 : * With some kernel config, the current mmap_lock's offset
623 : * inside 'mm_struct' is at 0x120, which is very optimal, as
624 : * its two hot fields 'count' and 'owner' sit in 2 different
625 : * cachelines, and when mmap_lock is highly contended, both
626 : * of the 2 fields will be accessed frequently, current layout
627 : * will help to reduce cache bouncing.
628 : *
629 : * So please be careful with adding new fields before
630 : * mmap_lock, which can easily push the 2 fields into one
631 : * cacheline.
632 : */
633 : struct rw_semaphore mmap_lock;
634 :
635 : struct list_head mmlist; /* List of maybe swapped mm's. These
636 : * are globally strung together off
637 : * init_mm.mmlist, and are protected
638 : * by mmlist_lock
639 : */
640 :
641 :
642 : unsigned long hiwater_rss; /* High-watermark of RSS usage */
643 : unsigned long hiwater_vm; /* High-water virtual memory usage */
644 :
645 : unsigned long total_vm; /* Total pages mapped */
646 : unsigned long locked_vm; /* Pages that have PG_mlocked set */
647 : atomic64_t pinned_vm; /* Refcount permanently increased */
648 : unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
649 : unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
650 : unsigned long stack_vm; /* VM_STACK */
651 : unsigned long def_flags;
652 :
653 : /**
654 : * @write_protect_seq: Locked when any thread is write
655 : * protecting pages mapped by this mm to enforce a later COW,
656 : * for instance during page table copying for fork().
657 : */
658 : seqcount_t write_protect_seq;
659 :
660 : spinlock_t arg_lock; /* protect the below fields */
661 :
662 : unsigned long start_code, end_code, start_data, end_data;
663 : unsigned long start_brk, brk, start_stack;
664 : unsigned long arg_start, arg_end, env_start, env_end;
665 :
666 : unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
667 :
668 : struct percpu_counter rss_stat[NR_MM_COUNTERS];
669 :
670 : struct linux_binfmt *binfmt;
671 :
672 : /* Architecture-specific MM context */
673 : mm_context_t context;
674 :
675 : unsigned long flags; /* Must use atomic bitops to access */
676 :
677 : #ifdef CONFIG_AIO
678 : spinlock_t ioctx_lock;
679 : struct kioctx_table __rcu *ioctx_table;
680 : #endif
681 : #ifdef CONFIG_MEMCG
682 : /*
683 : * "owner" points to a task that is regarded as the canonical
684 : * user/owner of this mm. All of the following must be true in
685 : * order for it to be changed:
686 : *
687 : * current == mm->owner
688 : * current->mm != mm
689 : * new_owner->mm == mm
690 : * new_owner->alloc_lock is held
691 : */
692 : struct task_struct __rcu *owner;
693 : #endif
694 : struct user_namespace *user_ns;
695 :
696 : /* store ref to file /proc/<pid>/exe symlink points to */
697 : struct file __rcu *exe_file;
698 : #ifdef CONFIG_MMU_NOTIFIER
699 : struct mmu_notifier_subscriptions *notifier_subscriptions;
700 : #endif
701 : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
702 : pgtable_t pmd_huge_pte; /* protected by page_table_lock */
703 : #endif
704 : #ifdef CONFIG_NUMA_BALANCING
705 : /*
706 : * numa_next_scan is the next time that PTEs will be remapped
707 : * PROT_NONE to trigger NUMA hinting faults; such faults gather
708 : * statistics and migrate pages to new nodes if necessary.
709 : */
710 : unsigned long numa_next_scan;
711 :
712 : /* Restart point for scanning and remapping PTEs. */
713 : unsigned long numa_scan_offset;
714 :
715 : /* numa_scan_seq prevents two threads remapping PTEs. */
716 : int numa_scan_seq;
717 : #endif
718 : /*
719 : * An operation with batched TLB flushing is going on. Anything
720 : * that can move process memory needs to flush the TLB when
721 : * moving a PROT_NONE mapped page.
722 : */
723 : atomic_t tlb_flush_pending;
724 : #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
725 : /* See flush_tlb_batched_pending() */
726 : atomic_t tlb_flush_batched;
727 : #endif
728 : struct uprobes_state uprobes_state;
729 : #ifdef CONFIG_PREEMPT_RT
730 : struct rcu_head delayed_drop;
731 : #endif
732 : #ifdef CONFIG_HUGETLB_PAGE
733 : atomic_long_t hugetlb_usage;
734 : #endif
735 : struct work_struct async_put_work;
736 :
737 : #ifdef CONFIG_IOMMU_SVA
738 : u32 pasid;
739 : #endif
740 : #ifdef CONFIG_KSM
741 : /*
742 : * Represent how many pages of this process are involved in KSM
743 : * merging.
744 : */
745 : unsigned long ksm_merging_pages;
746 : /*
747 : * Represent how many pages are checked for ksm merging
748 : * including merged and not merged.
749 : */
750 : unsigned long ksm_rmap_items;
751 : #endif
752 : #ifdef CONFIG_LRU_GEN
753 : struct {
754 : /* this mm_struct is on lru_gen_mm_list */
755 : struct list_head list;
756 : /*
757 : * Set when switching to this mm_struct, as a hint of
758 : * whether it has been used since the last time per-node
759 : * page table walkers cleared the corresponding bits.
760 : */
761 : unsigned long bitmap;
762 : #ifdef CONFIG_MEMCG
763 : /* points to the memcg of "owner" above */
764 : struct mem_cgroup *memcg;
765 : #endif
766 : } lru_gen;
767 : #endif /* CONFIG_LRU_GEN */
768 : } __randomize_layout;
769 :
770 : /*
771 : * The mm_cpumask needs to be at the end of mm_struct, because it
772 : * is dynamically sized based on nr_cpu_ids.
773 : */
774 : unsigned long cpu_bitmap[];
775 : };
776 :
777 : #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN)
778 : extern struct mm_struct init_mm;
779 :
780 : /* Pointer magic because the dynamic array size confuses some compilers. */
781 : static inline void mm_init_cpumask(struct mm_struct *mm)
782 : {
783 0 : unsigned long cpu_bitmap = (unsigned long)mm;
784 :
785 0 : cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
786 0 : cpumask_clear((struct cpumask *)cpu_bitmap);
787 : }
788 :
789 : /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
790 : static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
791 : {
792 : return (struct cpumask *)&mm->cpu_bitmap;
793 : }
794 :
795 : #ifdef CONFIG_LRU_GEN
796 :
797 : struct lru_gen_mm_list {
798 : /* mm_struct list for page table walkers */
799 : struct list_head fifo;
800 : /* protects the list above */
801 : spinlock_t lock;
802 : };
803 :
804 : void lru_gen_add_mm(struct mm_struct *mm);
805 : void lru_gen_del_mm(struct mm_struct *mm);
806 : #ifdef CONFIG_MEMCG
807 : void lru_gen_migrate_mm(struct mm_struct *mm);
808 : #endif
809 :
810 : static inline void lru_gen_init_mm(struct mm_struct *mm)
811 : {
812 : INIT_LIST_HEAD(&mm->lru_gen.list);
813 : mm->lru_gen.bitmap = 0;
814 : #ifdef CONFIG_MEMCG
815 : mm->lru_gen.memcg = NULL;
816 : #endif
817 : }
818 :
819 : static inline void lru_gen_use_mm(struct mm_struct *mm)
820 : {
821 : /*
822 : * When the bitmap is set, page reclaim knows this mm_struct has been
823 : * used since the last time it cleared the bitmap. So it might be worth
824 : * walking the page tables of this mm_struct to clear the accessed bit.
825 : */
826 : WRITE_ONCE(mm->lru_gen.bitmap, -1);
827 : }
828 :
829 : #else /* !CONFIG_LRU_GEN */
830 :
831 : static inline void lru_gen_add_mm(struct mm_struct *mm)
832 : {
833 : }
834 :
835 : static inline void lru_gen_del_mm(struct mm_struct *mm)
836 : {
837 : }
838 :
839 : #ifdef CONFIG_MEMCG
840 : static inline void lru_gen_migrate_mm(struct mm_struct *mm)
841 : {
842 : }
843 : #endif
844 :
845 : static inline void lru_gen_init_mm(struct mm_struct *mm)
846 : {
847 : }
848 :
849 : static inline void lru_gen_use_mm(struct mm_struct *mm)
850 : {
851 : }
852 :
853 : #endif /* CONFIG_LRU_GEN */
854 :
855 : struct vma_iterator {
856 : struct ma_state mas;
857 : };
858 :
859 : #define VMA_ITERATOR(name, __mm, __addr) \
860 : struct vma_iterator name = { \
861 : .mas = { \
862 : .tree = &(__mm)->mm_mt, \
863 : .index = __addr, \
864 : .node = MAS_START, \
865 : }, \
866 : }
867 :
868 : static inline void vma_iter_init(struct vma_iterator *vmi,
869 : struct mm_struct *mm, unsigned long addr)
870 : {
871 0 : mas_init(&vmi->mas, &mm->mm_mt, addr);
872 : }
873 :
874 : #ifdef CONFIG_SCHED_MM_CID
875 : /* Accessor for struct mm_struct's cidmask. */
876 : static inline cpumask_t *mm_cidmask(struct mm_struct *mm)
877 : {
878 : unsigned long cid_bitmap = (unsigned long)mm;
879 :
880 : cid_bitmap += offsetof(struct mm_struct, cpu_bitmap);
881 : /* Skip cpu_bitmap */
882 : cid_bitmap += cpumask_size();
883 : return (struct cpumask *)cid_bitmap;
884 : }
885 :
886 : static inline void mm_init_cid(struct mm_struct *mm)
887 : {
888 : raw_spin_lock_init(&mm->cid_lock);
889 : cpumask_clear(mm_cidmask(mm));
890 : }
891 :
892 : static inline unsigned int mm_cid_size(void)
893 : {
894 : return cpumask_size();
895 : }
896 : #else /* CONFIG_SCHED_MM_CID */
897 : static inline void mm_init_cid(struct mm_struct *mm) { }
898 : static inline unsigned int mm_cid_size(void)
899 : {
900 : return 0;
901 : }
902 : #endif /* CONFIG_SCHED_MM_CID */
903 :
904 : struct mmu_gather;
905 : extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
906 : extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
907 : extern void tlb_finish_mmu(struct mmu_gather *tlb);
908 :
909 : struct vm_fault;
910 :
911 : /**
912 : * typedef vm_fault_t - Return type for page fault handlers.
913 : *
914 : * Page fault handlers return a bitmask of %VM_FAULT values.
915 : */
916 : typedef __bitwise unsigned int vm_fault_t;
917 :
918 : /**
919 : * enum vm_fault_reason - Page fault handlers return a bitmask of
920 : * these values to tell the core VM what happened when handling the
921 : * fault. Used to decide whether a process gets delivered SIGBUS or
922 : * just gets major/minor fault counters bumped up.
923 : *
924 : * @VM_FAULT_OOM: Out Of Memory
925 : * @VM_FAULT_SIGBUS: Bad access
926 : * @VM_FAULT_MAJOR: Page read from storage
927 : * @VM_FAULT_HWPOISON: Hit poisoned small page
928 : * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
929 : * in upper bits
930 : * @VM_FAULT_SIGSEGV: segmentation fault
931 : * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
932 : * @VM_FAULT_LOCKED: ->fault locked the returned page
933 : * @VM_FAULT_RETRY: ->fault blocked, must retry
934 : * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
935 : * @VM_FAULT_DONE_COW: ->fault has fully handled COW
936 : * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
937 : * fsync() to complete (for synchronous page faults
938 : * in DAX)
939 : * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released
940 : * @VM_FAULT_HINDEX_MASK: mask HINDEX value
941 : *
942 : */
943 : enum vm_fault_reason {
944 : VM_FAULT_OOM = (__force vm_fault_t)0x000001,
945 : VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
946 : VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
947 : VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
948 : VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
949 : VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
950 : VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
951 : VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
952 : VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
953 : VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
954 : VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
955 : VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
956 : VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000,
957 : VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
958 : };
959 :
960 : /* Encode hstate index for a hwpoisoned large page */
961 : #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
962 : #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
963 :
964 : #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
965 : VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
966 : VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
967 :
968 : #define VM_FAULT_RESULT_TRACE \
969 : { VM_FAULT_OOM, "OOM" }, \
970 : { VM_FAULT_SIGBUS, "SIGBUS" }, \
971 : { VM_FAULT_MAJOR, "MAJOR" }, \
972 : { VM_FAULT_HWPOISON, "HWPOISON" }, \
973 : { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
974 : { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
975 : { VM_FAULT_NOPAGE, "NOPAGE" }, \
976 : { VM_FAULT_LOCKED, "LOCKED" }, \
977 : { VM_FAULT_RETRY, "RETRY" }, \
978 : { VM_FAULT_FALLBACK, "FALLBACK" }, \
979 : { VM_FAULT_DONE_COW, "DONE_COW" }, \
980 : { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
981 :
982 : struct vm_special_mapping {
983 : const char *name; /* The name, e.g. "[vdso]". */
984 :
985 : /*
986 : * If .fault is not provided, this points to a
987 : * NULL-terminated array of pages that back the special mapping.
988 : *
989 : * This must not be NULL unless .fault is provided.
990 : */
991 : struct page **pages;
992 :
993 : /*
994 : * If non-NULL, then this is called to resolve page faults
995 : * on the special mapping. If used, .pages is not checked.
996 : */
997 : vm_fault_t (*fault)(const struct vm_special_mapping *sm,
998 : struct vm_area_struct *vma,
999 : struct vm_fault *vmf);
1000 :
1001 : int (*mremap)(const struct vm_special_mapping *sm,
1002 : struct vm_area_struct *new_vma);
1003 : };
1004 :
1005 : enum tlb_flush_reason {
1006 : TLB_FLUSH_ON_TASK_SWITCH,
1007 : TLB_REMOTE_SHOOTDOWN,
1008 : TLB_LOCAL_SHOOTDOWN,
1009 : TLB_LOCAL_MM_SHOOTDOWN,
1010 : TLB_REMOTE_SEND_IPI,
1011 : NR_TLB_FLUSH_REASONS,
1012 : };
1013 :
1014 : /*
1015 : * A swap entry has to fit into a "unsigned long", as the entry is hidden
1016 : * in the "index" field of the swapper address space.
1017 : */
1018 : typedef struct {
1019 : unsigned long val;
1020 : } swp_entry_t;
1021 :
1022 : /**
1023 : * enum fault_flag - Fault flag definitions.
1024 : * @FAULT_FLAG_WRITE: Fault was a write fault.
1025 : * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
1026 : * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
1027 : * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
1028 : * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
1029 : * @FAULT_FLAG_TRIED: The fault has been tried once.
1030 : * @FAULT_FLAG_USER: The fault originated in userspace.
1031 : * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
1032 : * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
1033 : * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
1034 : * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a
1035 : * COW mapping, making sure that an exclusive anon page is
1036 : * mapped after the fault.
1037 : * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
1038 : * We should only access orig_pte if this flag set.
1039 : *
1040 : * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
1041 : * whether we would allow page faults to retry by specifying these two
1042 : * fault flags correctly. Currently there can be three legal combinations:
1043 : *
1044 : * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
1045 : * this is the first try
1046 : *
1047 : * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
1048 : * we've already tried at least once
1049 : *
1050 : * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
1051 : *
1052 : * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
1053 : * be used. Note that page faults can be allowed to retry for multiple times,
1054 : * in which case we'll have an initial fault with flags (a) then later on
1055 : * continuous faults with flags (b). We should always try to detect pending
1056 : * signals before a retry to make sure the continuous page faults can still be
1057 : * interrupted if necessary.
1058 : *
1059 : * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
1060 : * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
1061 : * applied to mappings that are not COW mappings.
1062 : */
1063 : enum fault_flag {
1064 : FAULT_FLAG_WRITE = 1 << 0,
1065 : FAULT_FLAG_MKWRITE = 1 << 1,
1066 : FAULT_FLAG_ALLOW_RETRY = 1 << 2,
1067 : FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
1068 : FAULT_FLAG_KILLABLE = 1 << 4,
1069 : FAULT_FLAG_TRIED = 1 << 5,
1070 : FAULT_FLAG_USER = 1 << 6,
1071 : FAULT_FLAG_REMOTE = 1 << 7,
1072 : FAULT_FLAG_INSTRUCTION = 1 << 8,
1073 : FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
1074 : FAULT_FLAG_UNSHARE = 1 << 10,
1075 : FAULT_FLAG_ORIG_PTE_VALID = 1 << 11,
1076 : };
1077 :
1078 : typedef unsigned int __bitwise zap_flags_t;
1079 :
1080 : /*
1081 : * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
1082 : * other. Here is what they mean, and how to use them:
1083 : *
1084 : *
1085 : * FIXME: For pages which are part of a filesystem, mappings are subject to the
1086 : * lifetime enforced by the filesystem and we need guarantees that longterm
1087 : * users like RDMA and V4L2 only establish mappings which coordinate usage with
1088 : * the filesystem. Ideas for this coordination include revoking the longterm
1089 : * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was
1090 : * added after the problem with filesystems was found FS DAX VMAs are
1091 : * specifically failed. Filesystem pages are still subject to bugs and use of
1092 : * FOLL_LONGTERM should be avoided on those pages.
1093 : *
1094 : * In the CMA case: long term pins in a CMA region would unnecessarily fragment
1095 : * that region. And so, CMA attempts to migrate the page before pinning, when
1096 : * FOLL_LONGTERM is specified.
1097 : *
1098 : * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
1099 : * but an additional pin counting system) will be invoked. This is intended for
1100 : * anything that gets a page reference and then touches page data (for example,
1101 : * Direct IO). This lets the filesystem know that some non-file-system entity is
1102 : * potentially changing the pages' data. In contrast to FOLL_GET (whose pages
1103 : * are released via put_page()), FOLL_PIN pages must be released, ultimately, by
1104 : * a call to unpin_user_page().
1105 : *
1106 : * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
1107 : * and separate refcounting mechanisms, however, and that means that each has
1108 : * its own acquire and release mechanisms:
1109 : *
1110 : * FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
1111 : *
1112 : * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
1113 : *
1114 : * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
1115 : * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
1116 : * calls applied to them, and that's perfectly OK. This is a constraint on the
1117 : * callers, not on the pages.)
1118 : *
1119 : * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
1120 : * directly by the caller. That's in order to help avoid mismatches when
1121 : * releasing pages: get_user_pages*() pages must be released via put_page(),
1122 : * while pin_user_pages*() pages must be released via unpin_user_page().
1123 : *
1124 : * Please see Documentation/core-api/pin_user_pages.rst for more information.
1125 : */
1126 :
1127 : enum {
1128 : /* check pte is writable */
1129 : FOLL_WRITE = 1 << 0,
1130 : /* do get_page on page */
1131 : FOLL_GET = 1 << 1,
1132 : /* give error on hole if it would be zero */
1133 : FOLL_DUMP = 1 << 2,
1134 : /* get_user_pages read/write w/o permission */
1135 : FOLL_FORCE = 1 << 3,
1136 : /*
1137 : * if a disk transfer is needed, start the IO and return without waiting
1138 : * upon it
1139 : */
1140 : FOLL_NOWAIT = 1 << 4,
1141 : /* do not fault in pages */
1142 : FOLL_NOFAULT = 1 << 5,
1143 : /* check page is hwpoisoned */
1144 : FOLL_HWPOISON = 1 << 6,
1145 : /* don't do file mappings */
1146 : FOLL_ANON = 1 << 7,
1147 : /*
1148 : * FOLL_LONGTERM indicates that the page will be held for an indefinite
1149 : * time period _often_ under userspace control. This is in contrast to
1150 : * iov_iter_get_pages(), whose usages are transient.
1151 : */
1152 : FOLL_LONGTERM = 1 << 8,
1153 : /* split huge pmd before returning */
1154 : FOLL_SPLIT_PMD = 1 << 9,
1155 : /* allow returning PCI P2PDMA pages */
1156 : FOLL_PCI_P2PDMA = 1 << 10,
1157 : /* allow interrupts from generic signals */
1158 : FOLL_INTERRUPTIBLE = 1 << 11,
1159 :
1160 : /* See also internal only FOLL flags in mm/internal.h */
1161 : };
1162 :
1163 : #endif /* _LINUX_MM_TYPES_H */
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