1	/* SPDX-License-Identifier: GPL-2.0 */
2	#ifndef _LINUX_MM_H
3	#define _LINUX_MM_H
4
5	#include <linux/errno.h>
6	#include <linux/mmdebug.h>
7	#include <linux/gfp.h>
8	#include <linux/bug.h>
9	#include <linux/list.h>
10	#include <linux/mmzone.h>
11	#include <linux/rbtree.h>
12	#include <linux/atomic.h>
13	#include <linux/debug_locks.h>
14	#include <linux/mm_types.h>
15	#include <linux/mmap_lock.h>
16	#include <linux/range.h>
17	#include <linux/pfn.h>
18	#include <linux/percpu-refcount.h>
19	#include <linux/bit_spinlock.h>
20	#include <linux/shrinker.h>
21	#include <linux/resource.h>
22	#include <linux/page_ext.h>
23	#include <linux/err.h>
24	#include <linux/page-flags.h>
25	#include <linux/page_ref.h>
26	#include <linux/overflow.h>
27	#include <linux/sizes.h>
28	#include <linux/sched.h>
29	#include <linux/pgtable.h>
30	#include <linux/kasan.h>
31	#include <linux/memremap.h>
32	#include <linux/slab.h>
33
34	struct mempolicy;
35	struct anon_vma;
36	struct anon_vma_chain;
37	struct user_struct;
38	struct pt_regs;
39
40	extern int sysctl_page_lock_unfairness;
41
42	void mm_core_init(void);
43	void init_mm_internals(void);
44
45	#ifndef CONFIG_NUMA /* Don't use mapnrs, do it properly */
46	extern unsigned long max_mapnr;
47
48	static inline void set_max_mapnr(unsigned long limit)
49	{
50	max_mapnr = limit;
51	}
52	#else
53	static inline void set_max_mapnr(unsigned long limit) { }
54	#endif
55
56	extern atomic_long_t _totalram_pages;
57	static inline unsigned long totalram_pages(void)
58	{
59	return (unsigned long)atomic_long_read(v: &_totalram_pages);
60	}
61
62	static inline void totalram_pages_inc(void)
63	{
64	atomic_long_inc(v: &_totalram_pages);
65	}
66
67	static inline void totalram_pages_dec(void)
68	{
69	atomic_long_dec(v: &_totalram_pages);
70	}
71
72	static inline void totalram_pages_add(long count)
73	{
74	atomic_long_add(i: count, v: &_totalram_pages);
75	}
76
77	extern void * high_memory;
78	extern int page_cluster;
79	extern const int page_cluster_max;
80
81	#ifdef CONFIG_SYSCTL
82	extern int sysctl_legacy_va_layout;
83	#else
84	#define sysctl_legacy_va_layout 0
85	#endif
86
87	#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
88	extern const int mmap_rnd_bits_min;
89	extern const int mmap_rnd_bits_max;
90	extern int mmap_rnd_bits __read_mostly;
91	#endif
92	#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
93	extern const int mmap_rnd_compat_bits_min;
94	extern const int mmap_rnd_compat_bits_max;
95	extern int mmap_rnd_compat_bits __read_mostly;
96	#endif
97
98	#include <asm/page.h>
99	#include <asm/processor.h>
100
101	#ifndef __pa_symbol
102	#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))
103	#endif
104
105	#ifndef page_to_virt
106	#define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x)))
107	#endif
108
109	#ifndef lm_alias
110	#define lm_alias(x) __va(__pa_symbol(x))
111	#endif
112
113	/*
114	* To prevent common memory management code establishing
115	* a zero page mapping on a read fault.
116	* This macro should be defined within <asm/pgtable.h>.
117	* s390 does this to prevent multiplexing of hardware bits
118	* related to the physical page in case of virtualization.
119	*/
120	#ifndef mm_forbids_zeropage
121	#define mm_forbids_zeropage(X) (0)
122	#endif
123
124	/*
125	* On some architectures it is expensive to call memset() for small sizes.
126	* If an architecture decides to implement their own version of
127	* mm_zero_struct_page they should wrap the defines below in a #ifndef and
128	* define their own version of this macro in <asm/pgtable.h>
129	*/
130	#if BITS_PER_LONG == 64
131	/* This function must be updated when the size of struct page grows above 96
132	* or reduces below 56. The idea that compiler optimizes out switch()
133	* statement, and only leaves move/store instructions. Also the compiler can
134	* combine write statements if they are both assignments and can be reordered,
135	* this can result in several of the writes here being dropped.
136	*/
137	#define mm_zero_struct_page(pp) __mm_zero_struct_page(pp)
138	static inline void __mm_zero_struct_page(struct page *page)
139	{
140	unsigned long *_pp = (void *)page;
141
142	/* Check that struct page is either 56, 64, 72, 80, 88 or 96 bytes */
143	BUILD_BUG_ON(sizeof(struct page) & 7);
144	BUILD_BUG_ON(sizeof(struct page) < 56);
145	BUILD_BUG_ON(sizeof(struct page) > 96);
146
147	switch (sizeof(struct page)) {
148	case 96:
149	_pp[11] = 0;
150	fallthrough;
151	case 88:
152	_pp[10] = 0;
153	fallthrough;
154	case 80:
155	_pp[9] = 0;
156	fallthrough;
157	case 72:
158	_pp[8] = 0;
159	fallthrough;
160	case 64:
161	_pp[7] = 0;
162	fallthrough;
163	case 56:
164	_pp[6] = 0;
165	_pp[5] = 0;
166	_pp[4] = 0;
167	_pp[3] = 0;
168	_pp[2] = 0;
169	_pp[1] = 0;
170	_pp[0] = 0;
171	}
172	}
173	#else
174	#define mm_zero_struct_page(pp) ((void)memset((pp), 0, sizeof(struct page)))
175	#endif
176
177	/*
178	* Default maximum number of active map areas, this limits the number of vmas
179	* per mm struct. Users can overwrite this number by sysctl but there is a
180	* problem.
181	*
182	* When a program's coredump is generated as ELF format, a section is created
183	* per a vma. In ELF, the number of sections is represented in unsigned short.
184	* This means the number of sections should be smaller than 65535 at coredump.
185	* Because the kernel adds some informative sections to a image of program at
186	* generating coredump, we need some margin. The number of extra sections is
187	* 1-3 now and depends on arch. We use "5" as safe margin, here.
188	*
189	* ELF extended numbering allows more than 65535 sections, so 16-bit bound is
190	* not a hard limit any more. Although some userspace tools can be surprised by
191	* that.
192	*/
193	#define MAPCOUNT_ELF_CORE_MARGIN (5)
194	#define DEFAULT_MAX_MAP_COUNT (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
195
196	extern int sysctl_max_map_count;
197
198	extern unsigned long sysctl_user_reserve_kbytes;
199	extern unsigned long sysctl_admin_reserve_kbytes;
200
201	extern int sysctl_overcommit_memory;
202	extern int sysctl_overcommit_ratio;
203	extern unsigned long sysctl_overcommit_kbytes;
204
205	int overcommit_ratio_handler(struct ctl_table *, int, void *, size_t *,
206	loff_t *);
207	int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
208	loff_t *);
209	int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
210	loff_t *);
211
212	#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
213	#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
214	#define folio_page_idx(folio, p) (page_to_pfn(p) - folio_pfn(folio))
215	#else
216	#define nth_page(page,n) ((page) + (n))
217	#define folio_page_idx(folio, p) ((p) - &(folio)->page)
218	#endif
219
220	/* to align the pointer to the (next) page boundary */
221	#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
222
223	/* to align the pointer to the (prev) page boundary */
224	#define PAGE_ALIGN_DOWN(addr) ALIGN_DOWN(addr, PAGE_SIZE)
225
226	/* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
227	#define PAGE_ALIGNED(addr) IS_ALIGNED((unsigned long)(addr), PAGE_SIZE)
228
229	#define lru_to_page(head) (list_entry((head)->prev, struct page, lru))
230	static inline struct folio *lru_to_folio(struct list_head *head)
231	{
232	return list_entry((head)->prev, struct folio, lru);
233	}
234
235	void setup_initial_init_mm(void *start_code, void *end_code,
236	void *end_data, void *brk);
237
238	/*
239	* Linux kernel virtual memory manager primitives.
240	* The idea being to have a "virtual" mm in the same way
241	* we have a virtual fs - giving a cleaner interface to the
242	* mm details, and allowing different kinds of memory mappings
243	* (from shared memory to executable loading to arbitrary
244	* mmap() functions).
245	*/
246
247	struct vm_area_struct *vm_area_alloc(struct mm_struct *);
248	struct vm_area_struct *vm_area_dup(struct vm_area_struct *);
249	void vm_area_free(struct vm_area_struct *);
250	/* Use only if VMA has no other users */
251	void __vm_area_free(struct vm_area_struct *vma);
252
253	#ifndef CONFIG_MMU
254	extern struct rb_root nommu_region_tree;
255	extern struct rw_semaphore nommu_region_sem;
256
257	extern unsigned int kobjsize(const void *objp);
258	#endif
259
260	/*
261	* vm_flags in vm_area_struct, see mm_types.h.
262	* When changing, update also include/trace/events/mmflags.h
263	*/
264	#define VM_NONE 0x00000000
265
266	#define VM_READ 0x00000001 /* currently active flags */
267	#define VM_WRITE 0x00000002
268	#define VM_EXEC 0x00000004
269	#define VM_SHARED 0x00000008
270
271	/* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
272	#define VM_MAYREAD 0x00000010 /* limits for mprotect() etc */
273	#define VM_MAYWRITE 0x00000020
274	#define VM_MAYEXEC 0x00000040
275	#define VM_MAYSHARE 0x00000080
276
277	#define VM_GROWSDOWN 0x00000100 /* general info on the segment */
278	#ifdef CONFIG_MMU
279	#define VM_UFFD_MISSING 0x00000200 /* missing pages tracking */
280	#else /* CONFIG_MMU */
281	#define VM_MAYOVERLAY 0x00000200 /* nommu: R/O MAP_PRIVATE mapping that might overlay a file mapping */
282	#define VM_UFFD_MISSING 0
283	#endif /* CONFIG_MMU */
284	#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */
285	#define VM_UFFD_WP 0x00001000 /* wrprotect pages tracking */
286
287	#define VM_LOCKED 0x00002000
288	#define VM_IO 0x00004000 /* Memory mapped I/O or similar */
289
290	/* Used by sys_madvise() */
291	#define VM_SEQ_READ 0x00008000 /* App will access data sequentially */
292	#define VM_RAND_READ 0x00010000 /* App will not benefit from clustered reads */
293
294	#define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */
295	#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
296	#define VM_LOCKONFAULT 0x00080000 /* Lock the pages covered when they are faulted in */
297	#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
298	#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */
299	#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
300	#define VM_SYNC 0x00800000 /* Synchronous page faults */
301	#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
302	#define VM_WIPEONFORK 0x02000000 /* Wipe VMA contents in child. */
303	#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
304
305	#ifdef CONFIG_MEM_SOFT_DIRTY
306	# define VM_SOFTDIRTY 0x08000000 /* Not soft dirty clean area */
307	#else
308	# define VM_SOFTDIRTY 0
309	#endif
310
311	#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
312	#define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */
313	#define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */
314	#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */
315
316	#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
317	#define VM_HIGH_ARCH_BIT_0 32 /* bit only usable on 64-bit architectures */
318	#define VM_HIGH_ARCH_BIT_1 33 /* bit only usable on 64-bit architectures */
319	#define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */
320	#define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */
321	#define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */
322	#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */
323	#define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0)
324	#define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1)
325	#define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2)
326	#define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3)
327	#define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4)
328	#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5)
329	#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
330
331	#ifdef CONFIG_ARCH_HAS_PKEYS
332	# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
333	# define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */
334	# define VM_PKEY_BIT1 VM_HIGH_ARCH_1 /* on x86 and 5-bit value on ppc64 */
335	# define VM_PKEY_BIT2 VM_HIGH_ARCH_2
336	# define VM_PKEY_BIT3 VM_HIGH_ARCH_3
337	#ifdef CONFIG_PPC
338	# define VM_PKEY_BIT4 VM_HIGH_ARCH_4
339	#else
340	# define VM_PKEY_BIT4 0
341	#endif
342	#endif /* CONFIG_ARCH_HAS_PKEYS */
343
344	#ifdef CONFIG_X86_USER_SHADOW_STACK
345	/*
346	* VM_SHADOW_STACK should not be set with VM_SHARED because of lack of
347	* support core mm.
348	*
349	* These VMAs will get a single end guard page. This helps userspace protect
350	* itself from attacks. A single page is enough for current shadow stack archs
351	* (x86). See the comments near alloc_shstk() in arch/x86/kernel/shstk.c
352	* for more details on the guard size.
353	*/
354	# define VM_SHADOW_STACK VM_HIGH_ARCH_5
355	#else
356	# define VM_SHADOW_STACK VM_NONE
357	#endif
358
359	#if defined(CONFIG_X86)
360	# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
361	#elif defined(CONFIG_PPC)
362	# define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
363	#elif defined(CONFIG_PARISC)
364	# define VM_GROWSUP VM_ARCH_1
365	#elif defined(CONFIG_SPARC64)
366	# define VM_SPARC_ADI VM_ARCH_1 /* Uses ADI tag for access control */
367	# define VM_ARCH_CLEAR VM_SPARC_ADI
368	#elif defined(CONFIG_ARM64)
369	# define VM_ARM64_BTI VM_ARCH_1 /* BTI guarded page, a.k.a. GP bit */
370	# define VM_ARCH_CLEAR VM_ARM64_BTI
371	#elif !defined(CONFIG_MMU)
372	# define VM_MAPPED_COPY VM_ARCH_1 /* T if mapped copy of data (nommu mmap) */
373	#endif
374
375	#if defined(CONFIG_ARM64_MTE)
376	# define VM_MTE VM_HIGH_ARCH_0 /* Use Tagged memory for access control */
377	# define VM_MTE_ALLOWED VM_HIGH_ARCH_1 /* Tagged memory permitted */
378	#else
379	# define VM_MTE VM_NONE
380	# define VM_MTE_ALLOWED VM_NONE
381	#endif
382
383	#ifndef VM_GROWSUP
384	# define VM_GROWSUP VM_NONE
385	#endif
386
387	#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
388	# define VM_UFFD_MINOR_BIT 38
389	# define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */
390	#else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
391	# define VM_UFFD_MINOR VM_NONE
392	#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
393
394	/* Bits set in the VMA until the stack is in its final location */
395	#define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY)
396
397	#define TASK_EXEC ((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0)
398
399	/* Common data flag combinations */
400	#define VM_DATA_FLAGS_TSK_EXEC (VM_READ | VM_WRITE | TASK_EXEC | \
401	VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
402	#define VM_DATA_FLAGS_NON_EXEC (VM_READ | VM_WRITE | VM_MAYREAD | \
403	VM_MAYWRITE | VM_MAYEXEC)
404	#define VM_DATA_FLAGS_EXEC (VM_READ | VM_WRITE | VM_EXEC | \
405	VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
406
407	#ifndef VM_DATA_DEFAULT_FLAGS /* arch can override this */
408	#define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_EXEC
409	#endif
410
411	#ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */
412	#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
413	#endif
414
415	#define VM_STARTGAP_FLAGS (VM_GROWSDOWN | VM_SHADOW_STACK)
416
417	#ifdef CONFIG_STACK_GROWSUP
418	#define VM_STACK VM_GROWSUP
419	#define VM_STACK_EARLY VM_GROWSDOWN
420	#else
421	#define VM_STACK VM_GROWSDOWN
422	#define VM_STACK_EARLY 0
423	#endif
424
425	#define VM_STACK_FLAGS (VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
426
427	/* VMA basic access permission flags */
428	#define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC)
429
430
431	/*
432	* Special vmas that are non-mergable, non-mlock()able.
433	*/
434	#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
435
436	/* This mask prevents VMA from being scanned with khugepaged */
437	#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB)
438
439	/* This mask defines which mm->def_flags a process can inherit its parent */
440	#define VM_INIT_DEF_MASK VM_NOHUGEPAGE
441
442	/* This mask represents all the VMA flag bits used by mlock */
443	#define VM_LOCKED_MASK (VM_LOCKED | VM_LOCKONFAULT)
444
445	/* Arch-specific flags to clear when updating VM flags on protection change */
446	#ifndef VM_ARCH_CLEAR
447	# define VM_ARCH_CLEAR VM_NONE
448	#endif
449	#define VM_FLAGS_CLEAR (ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR)
450
451	/*
452	* mapping from the currently active vm_flags protection bits (the
453	* low four bits) to a page protection mask..
454	*/
455
456	/*
457	* The default fault flags that should be used by most of the
458	* arch-specific page fault handlers.
459	*/
460	#define FAULT_FLAG_DEFAULT (FAULT_FLAG_ALLOW_RETRY | \
461	FAULT_FLAG_KILLABLE | \
462	FAULT_FLAG_INTERRUPTIBLE)
463
464	/**
465	* fault_flag_allow_retry_first - check ALLOW_RETRY the first time
466	* @flags: Fault flags.
467	*
468	* This is mostly used for places where we want to try to avoid taking
469	* the mmap_lock for too long a time when waiting for another condition
470	* to change, in which case we can try to be polite to release the
471	* mmap_lock in the first round to avoid potential starvation of other
472	* processes that would also want the mmap_lock.
473	*
474	* Return: true if the page fault allows retry and this is the first
475	* attempt of the fault handling; false otherwise.
476	*/
477	static inline bool fault_flag_allow_retry_first(enum fault_flag flags)
478	{
479	return (flags & FAULT_FLAG_ALLOW_RETRY) &&
480	(!(flags & FAULT_FLAG_TRIED));
481	}
482
483	#define FAULT_FLAG_TRACE \
484	{ FAULT_FLAG_WRITE, "WRITE" }, \
485	{ FAULT_FLAG_MKWRITE, "MKWRITE" }, \
486	{ FAULT_FLAG_ALLOW_RETRY, "ALLOW_RETRY" }, \
487	{ FAULT_FLAG_RETRY_NOWAIT, "RETRY_NOWAIT" }, \
488	{ FAULT_FLAG_KILLABLE, "KILLABLE" }, \
489	{ FAULT_FLAG_TRIED, "TRIED" }, \
490	{ FAULT_FLAG_USER, "USER" }, \
491	{ FAULT_FLAG_REMOTE, "REMOTE" }, \
492	{ FAULT_FLAG_INSTRUCTION, "INSTRUCTION" }, \
493	{ FAULT_FLAG_INTERRUPTIBLE, "INTERRUPTIBLE" }, \
494	{ FAULT_FLAG_VMA_LOCK, "VMA_LOCK" }
495
496	/*
497	* vm_fault is filled by the pagefault handler and passed to the vma's
498	* ->fault function. The vma's ->fault is responsible for returning a bitmask
499	* of VM_FAULT_xxx flags that give details about how the fault was handled.
500	*
501	* MM layer fills up gfp_mask for page allocations but fault handler might
502	* alter it if its implementation requires a different allocation context.
503	*
504	* pgoff should be used in favour of virtual_address, if possible.
505	*/
506	struct vm_fault {
507	const struct {
508	struct vm_area_struct *vma; /* Target VMA */
509	gfp_t gfp_mask; /* gfp mask to be used for allocations */
510	pgoff_t pgoff; /* Logical page offset based on vma */
511	unsigned long address; /* Faulting virtual address - masked */
512	unsigned long real_address; /* Faulting virtual address - unmasked */
513	};
514	enum fault_flag flags; /* FAULT_FLAG_xxx flags
515	* XXX: should really be 'const' */
516	pmd_t *pmd; /* Pointer to pmd entry matching
517	* the 'address' */
518	pud_t *pud; /* Pointer to pud entry matching
519	* the 'address'
520	*/
521	union {
522	pte_t orig_pte; /* Value of PTE at the time of fault */
523	pmd_t orig_pmd; /* Value of PMD at the time of fault,
524	* used by PMD fault only.
525	*/
526	};
527
528	struct page *cow_page; /* Page handler may use for COW fault */
529	struct page *page; /* ->fault handlers should return a
530	* page here, unless VM_FAULT_NOPAGE
531	* is set (which is also implied by
532	* VM_FAULT_ERROR).
533	*/
534	/* These three entries are valid only while holding ptl lock */
535	pte_t *pte; /* Pointer to pte entry matching
536	* the 'address'. NULL if the page
537	* table hasn't been allocated.
538	*/
539	spinlock_t *ptl; /* Page table lock.
540	* Protects pte page table if 'pte'
541	* is not NULL, otherwise pmd.
542	*/
543	pgtable_t prealloc_pte; /* Pre-allocated pte page table.
544	* vm_ops->map_pages() sets up a page
545	* table from atomic context.
546	* do_fault_around() pre-allocates
547	* page table to avoid allocation from
548	* atomic context.
549	*/
550	};
551
552	/*
553	* These are the virtual MM functions - opening of an area, closing and
554	* unmapping it (needed to keep files on disk up-to-date etc), pointer
555	* to the functions called when a no-page or a wp-page exception occurs.
556	*/
557	struct vm_operations_struct {
558	void (*open)(struct vm_area_struct * area);
559	/**
560	* @close: Called when the VMA is being removed from the MM.
561	* Context: User context. May sleep. Caller holds mmap_lock.
562	*/
563	void (*close)(struct vm_area_struct * area);
564	/* Called any time before splitting to check if it's allowed */
565	int (*may_split)(struct vm_area_struct *area, unsigned long addr);
566	int (*mremap)(struct vm_area_struct *area);
567	/*
568	* Called by mprotect() to make driver-specific permission
569	* checks before mprotect() is finalised. The VMA must not
570	* be modified. Returns 0 if mprotect() can proceed.
571	*/
572	int (*mprotect)(struct vm_area_struct *vma, unsigned long start,
573	unsigned long end, unsigned long newflags);
574	vm_fault_t (*fault)(struct vm_fault *vmf);
575	vm_fault_t (*huge_fault)(struct vm_fault *vmf, unsigned int order);
576	vm_fault_t (*map_pages)(struct vm_fault *vmf,
577	pgoff_t start_pgoff, pgoff_t end_pgoff);
578	unsigned long (*pagesize)(struct vm_area_struct * area);
579
580	/* notification that a previously read-only page is about to become
581	* writable, if an error is returned it will cause a SIGBUS */
582	vm_fault_t (*page_mkwrite)(struct vm_fault *vmf);
583
584	/* same as page_mkwrite when using VM_PFNMAP|VM_MIXEDMAP */
585	vm_fault_t (*pfn_mkwrite)(struct vm_fault *vmf);
586
587	/* called by access_process_vm when get_user_pages() fails, typically
588	* for use by special VMAs. See also generic_access_phys() for a generic
589	* implementation useful for any iomem mapping.
590	*/
591	int (*access)(struct vm_area_struct *vma, unsigned long addr,
592	void *buf, int len, int write);
593
594	/* Called by the /proc/PID/maps code to ask the vma whether it
595	* has a special name. Returning non-NULL will also cause this
596	* vma to be dumped unconditionally. */
597	const char *(*name)(struct vm_area_struct *vma);
598
599	#ifdef CONFIG_NUMA
600	/*
601	* set_policy() op must add a reference to any non-NULL @new mempolicy
602	* to hold the policy upon return. Caller should pass NULL @new to
603	* remove a policy and fall back to surrounding context--i.e. do not
604	* install a MPOL_DEFAULT policy, nor the task or system default
605	* mempolicy.
606	*/
607	int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
608
609	/*
610	* get_policy() op must add reference [mpol_get()] to any policy at
611	* (vma,addr) marked as MPOL_SHARED. The shared policy infrastructure
612	* in mm/mempolicy.c will do this automatically.
613	* get_policy() must NOT add a ref if the policy at (vma,addr) is not
614	* marked as MPOL_SHARED. vma policies are protected by the mmap_lock.
615	* If no [shared/vma] mempolicy exists at the addr, get_policy() op
616	* must return NULL--i.e., do not "fallback" to task or system default
617	* policy.
618	*/
619	struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
620	unsigned long addr, pgoff_t *ilx);
621	#endif
622	/*
623	* Called by vm_normal_page() for special PTEs to find the
624	* page for @addr. This is useful if the default behavior
625	* (using pte_page()) would not find the correct page.
626	*/
627	struct page *(*find_special_page)(struct vm_area_struct *vma,
628	unsigned long addr);
629	};
630
631	#ifdef CONFIG_NUMA_BALANCING
632	static inline void vma_numab_state_init(struct vm_area_struct *vma)
633	{
634	vma->numab_state = NULL;
635	}
636	static inline void vma_numab_state_free(struct vm_area_struct *vma)
637	{
638	kfree(objp: vma->numab_state);
639	}
640	#else
641	static inline void vma_numab_state_init(struct vm_area_struct *vma) {}
642	static inline void vma_numab_state_free(struct vm_area_struct *vma) {}
643	#endif /* CONFIG_NUMA_BALANCING */
644
645	#ifdef CONFIG_PER_VMA_LOCK
646	/*
647	* Try to read-lock a vma. The function is allowed to occasionally yield false
648	* locked result to avoid performance overhead, in which case we fall back to
649	* using mmap_lock. The function should never yield false unlocked result.
650	*/
651	static inline bool vma_start_read(struct vm_area_struct *vma)
652	{
653	/*
654	* Check before locking. A race might cause false locked result.
655	* We can use READ_ONCE() for the mm_lock_seq here, and don't need
656	* ACQUIRE semantics, because this is just a lockless check whose result
657	* we don't rely on for anything - the mm_lock_seq read against which we
658	* need ordering is below.
659	*/
660	if (READ_ONCE(vma->vm_lock_seq) == READ_ONCE(vma->vm_mm->mm_lock_seq))
661	return false;
662
663	if (unlikely(down_read_trylock(&vma->vm_lock->lock) == 0))
664	return false;
665
666	/*
667	* Overflow might produce false locked result.
668	* False unlocked result is impossible because we modify and check
669	* vma->vm_lock_seq under vma->vm_lock protection and mm->mm_lock_seq
670	* modification invalidates all existing locks.
671	*
672	* We must use ACQUIRE semantics for the mm_lock_seq so that if we are
673	* racing with vma_end_write_all(), we only start reading from the VMA
674	* after it has been unlocked.
675	* This pairs with RELEASE semantics in vma_end_write_all().
676	*/
677	if (unlikely(vma->vm_lock_seq == smp_load_acquire(&vma->vm_mm->mm_lock_seq))) {
678	up_read(sem: &vma->vm_lock->lock);
679	return false;
680	}
681	return true;
682	}
683
684	static inline void vma_end_read(struct vm_area_struct *vma)
685	{
686	rcu_read_lock(); /* keeps vma alive till the end of up_read */
687	up_read(sem: &vma->vm_lock->lock);
688	rcu_read_unlock();
689	}
690
691	/* WARNING! Can only be used if mmap_lock is expected to be write-locked */
692	static bool __is_vma_write_locked(struct vm_area_struct *vma, int *mm_lock_seq)
693	{
694	mmap_assert_write_locked(mm: vma->vm_mm);
695
696	/*
697	* current task is holding mmap_write_lock, both vma->vm_lock_seq and
698	* mm->mm_lock_seq can't be concurrently modified.
699	*/
700	*mm_lock_seq = vma->vm_mm->mm_lock_seq;
701	return (vma->vm_lock_seq == *mm_lock_seq);
702	}
703
704	/*
705	* Begin writing to a VMA.
706	* Exclude concurrent readers under the per-VMA lock until the currently
707	* write-locked mmap_lock is dropped or downgraded.
708	*/
709	static inline void vma_start_write(struct vm_area_struct *vma)
710	{
711	int mm_lock_seq;
712
713	if (__is_vma_write_locked(vma, mm_lock_seq: &mm_lock_seq))
714	return;
715
716	down_write(sem: &vma->vm_lock->lock);
717	/*
718	* We should use WRITE_ONCE() here because we can have concurrent reads
719	* from the early lockless pessimistic check in vma_start_read().
720	* We don't really care about the correctness of that early check, but
721	* we should use WRITE_ONCE() for cleanliness and to keep KCSAN happy.
722	*/
723	WRITE_ONCE(vma->vm_lock_seq, mm_lock_seq);
724	up_write(sem: &vma->vm_lock->lock);
725	}
726
727	static inline void vma_assert_write_locked(struct vm_area_struct *vma)
728	{
729	int mm_lock_seq;
730
731	VM_BUG_ON_VMA(!__is_vma_write_locked(vma, &mm_lock_seq), vma);
732	}
733
734	static inline void vma_assert_locked(struct vm_area_struct *vma)
735	{
736	if (!rwsem_is_locked(sem: &vma->vm_lock->lock))
737	vma_assert_write_locked(vma);
738	}
739
740	static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached)
741	{
742	/* When detaching vma should be write-locked */
743	if (detached)
744	vma_assert_write_locked(vma);
745	vma->detached = detached;
746	}
747
748	static inline void release_fault_lock(struct vm_fault *vmf)
749	{
750	if (vmf->flags & FAULT_FLAG_VMA_LOCK)
751	vma_end_read(vma: vmf->vma);
752	else
753	mmap_read_unlock(mm: vmf->vma->vm_mm);
754	}
755
756	static inline void assert_fault_locked(struct vm_fault *vmf)
757	{
758	if (vmf->flags & FAULT_FLAG_VMA_LOCK)
759	vma_assert_locked(vma: vmf->vma);
760	else
761	mmap_assert_locked(mm: vmf->vma->vm_mm);
762	}
763
764	struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
765	unsigned long address);
766
767	#else /* CONFIG_PER_VMA_LOCK */
768
769	static inline bool vma_start_read(struct vm_area_struct *vma)
770	{ return false; }
771	static inline void vma_end_read(struct vm_area_struct *vma) {}
772	static inline void vma_start_write(struct vm_area_struct *vma) {}
773	static inline void vma_assert_write_locked(struct vm_area_struct *vma)
774	{ mmap_assert_write_locked(vma->vm_mm); }
775	static inline void vma_mark_detached(struct vm_area_struct *vma,
776	bool detached) {}
777
778	static inline struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
779	unsigned long address)
780	{
781	return NULL;
782	}
783
784	static inline void release_fault_lock(struct vm_fault *vmf)
785	{
786	mmap_read_unlock(vmf->vma->vm_mm);
787	}
788
789	static inline void assert_fault_locked(struct vm_fault *vmf)
790	{
791	mmap_assert_locked(vmf->vma->vm_mm);
792	}
793
794	#endif /* CONFIG_PER_VMA_LOCK */
795
796	extern const struct vm_operations_struct vma_dummy_vm_ops;
797
798	/*
799	* WARNING: vma_init does not initialize vma->vm_lock.
800	* Use vm_area_alloc()/vm_area_free() if vma needs locking.
801	*/
802	static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
803	{
804	memset(vma, 0, sizeof(*vma));
805	vma->vm_mm = mm;
806	vma->vm_ops = &vma_dummy_vm_ops;
807	INIT_LIST_HEAD(list: &vma->anon_vma_chain);
808	vma_mark_detached(vma, detached: false);
809	vma_numab_state_init(vma);
810	}
811
812	/* Use when VMA is not part of the VMA tree and needs no locking */
813	static inline void vm_flags_init(struct vm_area_struct *vma,
814	vm_flags_t flags)
815	{
816	ACCESS_PRIVATE(vma, __vm_flags) = flags;
817	}
818
819	/*
820	* Use when VMA is part of the VMA tree and modifications need coordination
821	* Note: vm_flags_reset and vm_flags_reset_once do not lock the vma and
822	* it should be locked explicitly beforehand.
823	*/
824	static inline void vm_flags_reset(struct vm_area_struct *vma,
825	vm_flags_t flags)
826	{
827	vma_assert_write_locked(vma);
828	vm_flags_init(vma, flags);
829	}
830
831	static inline void vm_flags_reset_once(struct vm_area_struct *vma,
832	vm_flags_t flags)
833	{
834	vma_assert_write_locked(vma);
835	WRITE_ONCE(ACCESS_PRIVATE(vma, __vm_flags), flags);
836	}
837
838	static inline void vm_flags_set(struct vm_area_struct *vma,
839	vm_flags_t flags)
840	{
841	vma_start_write(vma);
842	ACCESS_PRIVATE(vma, __vm_flags) |= flags;
843	}
844
845	static inline void vm_flags_clear(struct vm_area_struct *vma,
846	vm_flags_t flags)
847	{
848	vma_start_write(vma);
849	ACCESS_PRIVATE(vma, __vm_flags) &= ~flags;
850	}
851
852	/*
853	* Use only if VMA is not part of the VMA tree or has no other users and
854	* therefore needs no locking.
855	*/
856	static inline void __vm_flags_mod(struct vm_area_struct *vma,
857	vm_flags_t set, vm_flags_t clear)
858	{
859	vm_flags_init(vma, flags: (vma->vm_flags | set) & ~clear);
860	}
861
862	/*
863	* Use only when the order of set/clear operations is unimportant, otherwise
864	* use vm_flags_{set|clear} explicitly.
865	*/
866	static inline void vm_flags_mod(struct vm_area_struct *vma,
867	vm_flags_t set, vm_flags_t clear)
868	{
869	vma_start_write(vma);
870	__vm_flags_mod(vma, set, clear);
871	}
872
873	static inline void vma_set_anonymous(struct vm_area_struct *vma)
874	{
875	vma->vm_ops = NULL;
876	}
877
878	static inline bool vma_is_anonymous(struct vm_area_struct *vma)
879	{
880	return !vma->vm_ops;
881	}
882
883	/*
884	* Indicate if the VMA is a heap for the given task; for
885	* /proc/PID/maps that is the heap of the main task.
886	*/
887	static inline bool vma_is_initial_heap(const struct vm_area_struct *vma)
888	{
889	return vma->vm_start <= vma->vm_mm->brk &&
890	vma->vm_end >= vma->vm_mm->start_brk;
891	}
892
893	/*
894	* Indicate if the VMA is a stack for the given task; for
895	* /proc/PID/maps that is the stack of the main task.
896	*/
897	static inline bool vma_is_initial_stack(const struct vm_area_struct *vma)
898	{
899	/*
900	* We make no effort to guess what a given thread considers to be
901	* its "stack". It's not even well-defined for programs written
902	* languages like Go.
903	*/
904	return vma->vm_start <= vma->vm_mm->start_stack &&
905	vma->vm_end >= vma->vm_mm->start_stack;
906	}
907
908	static inline bool vma_is_temporary_stack(struct vm_area_struct *vma)
909	{
910	int maybe_stack = vma->vm_flags & (VM_GROWSDOWN | VM_GROWSUP);
911
912	if (!maybe_stack)
913	return false;
914
915	if ((vma->vm_flags & VM_STACK_INCOMPLETE_SETUP) ==
916	VM_STACK_INCOMPLETE_SETUP)
917	return true;
918
919	return false;
920	}
921
922	static inline bool vma_is_foreign(struct vm_area_struct *vma)
923	{
924	if (!current->mm)
925	return true;
926
927	if (current->mm != vma->vm_mm)
928	return true;
929
930	return false;
931	}
932
933	static inline bool vma_is_accessible(struct vm_area_struct *vma)
934	{
935	return vma->vm_flags & VM_ACCESS_FLAGS;
936	}
937
938	static inline bool is_shared_maywrite(vm_flags_t vm_flags)
939	{
940	return (vm_flags & (VM_SHARED | VM_MAYWRITE)) ==
941	(VM_SHARED | VM_MAYWRITE);
942	}
943
944	static inline bool vma_is_shared_maywrite(struct vm_area_struct *vma)
945	{
946	return is_shared_maywrite(vm_flags: vma->vm_flags);
947	}
948
949	static inline
950	struct vm_area_struct *vma_find(struct vma_iterator *vmi, unsigned long max)
951	{
952	return mas_find(mas: &vmi->mas, max: max - 1);
953	}
954
955	static inline struct vm_area_struct *vma_next(struct vma_iterator *vmi)
956	{
957	/*
958	* Uses mas_find() to get the first VMA when the iterator starts.
959	* Calling mas_next() could skip the first entry.
960	*/
961	return mas_find(mas: &vmi->mas, ULONG_MAX);
962	}
963
964	static inline
965	struct vm_area_struct *vma_iter_next_range(struct vma_iterator *vmi)
966	{
967	return mas_next_range(mas: &vmi->mas, ULONG_MAX);
968	}
969
970
971	static inline struct vm_area_struct *vma_prev(struct vma_iterator *vmi)
972	{
973	return mas_prev(mas: &vmi->mas, min: 0);
974	}
975
976	static inline
977	struct vm_area_struct *vma_iter_prev_range(struct vma_iterator *vmi)
978	{
979	return mas_prev_range(mas: &vmi->mas, max: 0);
980	}
981
982	static inline unsigned long vma_iter_addr(struct vma_iterator *vmi)
983	{
984	return vmi->mas.index;
985	}
986
987	static inline unsigned long vma_iter_end(struct vma_iterator *vmi)
988	{
989	return vmi->mas.last + 1;
990	}
991	static inline int vma_iter_bulk_alloc(struct vma_iterator *vmi,
992	unsigned long count)
993	{
994	return mas_expected_entries(mas: &vmi->mas, nr_entries: count);
995	}
996
997	/* Free any unused preallocations */
998	static inline void vma_iter_free(struct vma_iterator *vmi)
999	{
1000	mas_destroy(mas: &vmi->mas);
1001	}
1002
1003	static inline int vma_iter_bulk_store(struct vma_iterator *vmi,
1004	struct vm_area_struct *vma)
1005	{
1006	vmi->mas.index = vma->vm_start;
1007	vmi->mas.last = vma->vm_end - 1;
1008	mas_store(mas: &vmi->mas, entry: vma);
1009	if (unlikely(mas_is_err(&vmi->mas)))
1010	return -ENOMEM;
1011
1012	return 0;
1013	}
1014
1015	static inline void vma_iter_invalidate(struct vma_iterator *vmi)
1016	{
1017	mas_pause(mas: &vmi->mas);
1018	}
1019
1020	static inline void vma_iter_set(struct vma_iterator *vmi, unsigned long addr)
1021	{
1022	mas_set(mas: &vmi->mas, index: addr);
1023	}
1024
1025	#define for_each_vma(__vmi, __vma) \
1026	while (((__vma) = vma_next(&(__vmi))) != NULL)
1027
1028	/* The MM code likes to work with exclusive end addresses */
1029	#define for_each_vma_range(__vmi, __vma, __end) \
1030	while (((__vma) = vma_find(&(__vmi), (__end))) != NULL)
1031
1032	#ifdef CONFIG_SHMEM
1033	/*
1034	* The vma_is_shmem is not inline because it is used only by slow
1035	* paths in userfault.
1036	*/
1037	bool vma_is_shmem(struct vm_area_struct *vma);
1038	bool vma_is_anon_shmem(struct vm_area_struct *vma);
1039	#else
1040	static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; }
1041	static inline bool vma_is_anon_shmem(struct vm_area_struct *vma) { return false; }
1042	#endif
1043
1044	int vma_is_stack_for_current(struct vm_area_struct *vma);
1045
1046	/* flush_tlb_range() takes a vma, not a mm, and can care about flags */
1047	#define TLB_FLUSH_VMA(mm,flags) { .vm_mm = (mm), .vm_flags = (flags) }
1048
1049	struct mmu_gather;
1050	struct inode;
1051
1052	/*
1053	* compound_order() can be called without holding a reference, which means
1054	* that niceties like page_folio() don't work. These callers should be
1055	* prepared to handle wild return values. For example, PG_head may be
1056	* set before the order is initialised, or this may be a tail page.
1057	* See compaction.c for some good examples.
1058	*/
1059	static inline unsigned int compound_order(struct page *page)
1060	{
1061	struct folio *folio = (struct folio *)page;
1062
1063	if (!test_bit(PG_head, &folio->flags))
1064	return 0;
1065	return folio->_flags_1 & 0xff;
1066	}
1067
1068	/**
1069	* folio_order - The allocation order of a folio.
1070	* @folio: The folio.
1071	*
1072	* A folio is composed of 2^order pages. See get_order() for the definition
1073	* of order.
1074	*
1075	* Return: The order of the folio.
1076	*/
1077	static inline unsigned int folio_order(struct folio *folio)
1078	{
1079	if (!folio_test_large(folio))
1080	return 0;
1081	return folio->_flags_1 & 0xff;
1082	}
1083
1084	#include <linux/huge_mm.h>
1085
1086	/*
1087	* Methods to modify the page usage count.
1088	*
1089	* What counts for a page usage:
1090	* - cache mapping (page->mapping)
1091	* - private data (page->private)
1092	* - page mapped in a task's page tables, each mapping
1093	* is counted separately
1094	*
1095	* Also, many kernel routines increase the page count before a critical
1096	* routine so they can be sure the page doesn't go away from under them.
1097	*/
1098
1099	/*
1100	* Drop a ref, return true if the refcount fell to zero (the page has no users)
1101	*/
1102	static inline int put_page_testzero(struct page *page)
1103	{
1104	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
1105	return page_ref_dec_and_test(page);
1106	}
1107
1108	static inline int folio_put_testzero(struct folio *folio)
1109	{
1110	return put_page_testzero(page: &folio->page);
1111	}
1112
1113	/*
1114	* Try to grab a ref unless the page has a refcount of zero, return false if
1115	* that is the case.
1116	* This can be called when MMU is off so it must not access
1117	* any of the virtual mappings.
1118	*/
1119	static inline bool get_page_unless_zero(struct page *page)
1120	{
1121	return page_ref_add_unless(page, nr: 1, u: 0);
1122	}
1123
1124	static inline struct folio *folio_get_nontail_page(struct page *page)
1125	{
1126	if (unlikely(!get_page_unless_zero(page)))
1127	return NULL;
1128	return (struct folio *)page;
1129	}
1130
1131	extern int page_is_ram(unsigned long pfn);
1132
1133	enum {
1134	REGION_INTERSECTS,
1135	REGION_DISJOINT,
1136	REGION_MIXED,
1137	};
1138
1139	int region_intersects(resource_size_t offset, size_t size, unsigned long flags,
1140	unsigned long desc);
1141
1142	/* Support for virtually mapped pages */
1143	struct page *vmalloc_to_page(const void *addr);
1144	unsigned long vmalloc_to_pfn(const void *addr);
1145
1146	/*
1147	* Determine if an address is within the vmalloc range
1148	*
1149	* On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
1150	* is no special casing required.
1151	*/
1152	#ifdef CONFIG_MMU
1153	extern bool is_vmalloc_addr(const void *x);
1154	extern int is_vmalloc_or_module_addr(const void *x);
1155	#else
1156	static inline bool is_vmalloc_addr(const void *x)
1157	{
1158	return false;
1159	}
1160	static inline int is_vmalloc_or_module_addr(const void *x)
1161	{
1162	return 0;
1163	}
1164	#endif
1165
1166	/*
1167	* How many times the entire folio is mapped as a single unit (eg by a
1168	* PMD or PUD entry). This is probably not what you want, except for
1169	* debugging purposes - it does not include PTE-mapped sub-pages; look
1170	* at folio_mapcount() or page_mapcount() or total_mapcount() instead.
1171	*/
1172	static inline int folio_entire_mapcount(struct folio *folio)
1173	{
1174	VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
1175	return atomic_read(v: &folio->_entire_mapcount) + 1;
1176	}
1177
1178	/*
1179	* The atomic page->_mapcount, starts from -1: so that transitions
1180	* both from it and to it can be tracked, using atomic_inc_and_test
1181	* and atomic_add_negative(-1).
1182	*/
1183	static inline void page_mapcount_reset(struct page *page)
1184	{
1185	atomic_set(v: &(page)->_mapcount, i: -1);
1186	}
1187
1188	/**
1189	* page_mapcount() - Number of times this precise page is mapped.
1190	* @page: The page.
1191	*
1192	* The number of times this page is mapped. If this page is part of
1193	* a large folio, it includes the number of times this page is mapped
1194	* as part of that folio.
1195	*
1196	* The result is undefined for pages which cannot be mapped into userspace.
1197	* For example SLAB or special types of pages. See function page_has_type().
1198	* They use this field in struct page differently.
1199	*/
1200	static inline int page_mapcount(struct page *page)
1201	{
1202	int mapcount = atomic_read(v: &page->_mapcount) + 1;
1203
1204	if (unlikely(PageCompound(page)))
1205	mapcount += folio_entire_mapcount(page_folio(page));
1206
1207	return mapcount;
1208	}
1209
1210	int folio_total_mapcount(struct folio *folio);
1211
1212	/**
1213	* folio_mapcount() - Calculate the number of mappings of this folio.
1214	* @folio: The folio.
1215	*
1216	* A large folio tracks both how many times the entire folio is mapped,
1217	* and how many times each individual page in the folio is mapped.
1218	* This function calculates the total number of times the folio is
1219	* mapped.
1220	*
1221	* Return: The number of times this folio is mapped.
1222	*/
1223	static inline int folio_mapcount(struct folio *folio)
1224	{
1225	if (likely(!folio_test_large(folio)))
1226	return atomic_read(v: &folio->_mapcount) + 1;
1227	return folio_total_mapcount(folio);
1228	}
1229
1230	static inline int total_mapcount(struct page *page)
1231	{
1232	if (likely(!PageCompound(page)))
1233	return atomic_read(v: &page->_mapcount) + 1;
1234	return folio_total_mapcount(page_folio(page));
1235	}
1236
1237	static inline bool folio_large_is_mapped(struct folio *folio)
1238	{
1239	/*
1240	* Reading _entire_mapcount below could be omitted if hugetlb
1241	* participated in incrementing nr_pages_mapped when compound mapped.
1242	*/
1243	return atomic_read(v: &folio->_nr_pages_mapped) > 0 ||
1244	atomic_read(v: &folio->_entire_mapcount) >= 0;
1245	}
1246
1247	/**
1248	* folio_mapped - Is this folio mapped into userspace?
1249	* @folio: The folio.
1250	*
1251	* Return: True if any page in this folio is referenced by user page tables.
1252	*/
1253	static inline bool folio_mapped(struct folio *folio)
1254	{
1255	if (likely(!folio_test_large(folio)))
1256	return atomic_read(v: &folio->_mapcount) >= 0;
1257	return folio_large_is_mapped(folio);
1258	}
1259
1260	/*
1261	* Return true if this page is mapped into pagetables.
1262	* For compound page it returns true if any sub-page of compound page is mapped,
1263	* even if this particular sub-page is not itself mapped by any PTE or PMD.
1264	*/
1265	static inline bool page_mapped(struct page *page)
1266	{
1267	if (likely(!PageCompound(page)))
1268	return atomic_read(v: &page->_mapcount) >= 0;
1269	return folio_large_is_mapped(page_folio(page));
1270	}
1271
1272	static inline struct page *virt_to_head_page(const void *x)
1273	{
1274	struct page *page = virt_to_page(x);
1275
1276	return compound_head(page);
1277	}
1278
1279	static inline struct folio *virt_to_folio(const void *x)
1280	{
1281	struct page *page = virt_to_page(x);
1282
1283	return page_folio(page);
1284	}
1285
1286	void __folio_put(struct folio *folio);
1287
1288	void put_pages_list(struct list_head *pages);
1289
1290	void split_page(struct page *page, unsigned int order);
1291	void folio_copy(struct folio *dst, struct folio *src);
1292
1293	unsigned long nr_free_buffer_pages(void);
1294
1295	void destroy_large_folio(struct folio *folio);
1296
1297	/* Returns the number of bytes in this potentially compound page. */
1298	static inline unsigned long page_size(struct page *page)
1299	{
1300	return PAGE_SIZE << compound_order(page);
1301	}
1302
1303	/* Returns the number of bits needed for the number of bytes in a page */
1304	static inline unsigned int page_shift(struct page *page)
1305	{
1306	return PAGE_SHIFT + compound_order(page);
1307	}
1308
1309	/**
1310	* thp_order - Order of a transparent huge page.
1311	* @page: Head page of a transparent huge page.
1312	*/
1313	static inline unsigned int thp_order(struct page *page)
1314	{
1315	VM_BUG_ON_PGFLAGS(PageTail(page), page);
1316	return compound_order(page);
1317	}
1318
1319	/**
1320	* thp_size - Size of a transparent huge page.
1321	* @page: Head page of a transparent huge page.
1322	*
1323	* Return: Number of bytes in this page.
1324	*/
1325	static inline unsigned long thp_size(struct page *page)
1326	{
1327	return PAGE_SIZE << thp_order(page);
1328	}
1329
1330	#ifdef CONFIG_MMU
1331	/*
1332	* Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1333	* servicing faults for write access. In the normal case, do always want
1334	* pte_mkwrite. But get_user_pages can cause write faults for mappings
1335	* that do not have writing enabled, when used by access_process_vm.
1336	*/
1337	static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1338	{
1339	if (likely(vma->vm_flags & VM_WRITE))
1340	pte = pte_mkwrite(pte, vma);
1341	return pte;
1342	}
1343
1344	vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page);
1345	void set_pte_range(struct vm_fault *vmf, struct folio *folio,
1346	struct page *page, unsigned int nr, unsigned long addr);
1347
1348	vm_fault_t finish_fault(struct vm_fault *vmf);
1349	#endif
1350
1351	/*
1352	* Multiple processes may "see" the same page. E.g. for untouched
1353	* mappings of /dev/null, all processes see the same page full of
1354	* zeroes, and text pages of executables and shared libraries have
1355	* only one copy in memory, at most, normally.
1356	*
1357	* For the non-reserved pages, page_count(page) denotes a reference count.
1358	* page_count() == 0 means the page is free. page->lru is then used for
1359	* freelist management in the buddy allocator.
1360	* page_count() > 0 means the page has been allocated.
1361	*
1362	* Pages are allocated by the slab allocator in order to provide memory
1363	* to kmalloc and kmem_cache_alloc. In this case, the management of the
1364	* page, and the fields in 'struct page' are the responsibility of mm/slab.c
1365	* unless a particular usage is carefully commented. (the responsibility of
1366	* freeing the kmalloc memory is the caller's, of course).
1367	*
1368	* A page may be used by anyone else who does a __get_free_page().
1369	* In this case, page_count still tracks the references, and should only
1370	* be used through the normal accessor functions. The top bits of page->flags
1371	* and page->virtual store page management information, but all other fields
1372	* are unused and could be used privately, carefully. The management of this
1373	* page is the responsibility of the one who allocated it, and those who have
1374	* subsequently been given references to it.
1375	*
1376	* The other pages (we may call them "pagecache pages") are completely
1377	* managed by the Linux memory manager: I/O, buffers, swapping etc.
1378	* The following discussion applies only to them.
1379	*
1380	* A pagecache page contains an opaque `private' member, which belongs to the
1381	* page's address_space. Usually, this is the address of a circular list of
1382	* the page's disk buffers. PG_private must be set to tell the VM to call
1383	* into the filesystem to release these pages.
1384	*
1385	* A page may belong to an inode's memory mapping. In this case, page->mapping
1386	* is the pointer to the inode, and page->index is the file offset of the page,
1387	* in units of PAGE_SIZE.
1388	*
1389	* If pagecache pages are not associated with an inode, they are said to be
1390	* anonymous pages. These may become associated with the swapcache, and in that
1391	* case PG_swapcache is set, and page->private is an offset into the swapcache.
1392	*
1393	* In either case (swapcache or inode backed), the pagecache itself holds one
1394	* reference to the page. Setting PG_private should also increment the
1395	* refcount. The each user mapping also has a reference to the page.
1396	*
1397	* The pagecache pages are stored in a per-mapping radix tree, which is
1398	* rooted at mapping->i_pages, and indexed by offset.
1399	* Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
1400	* lists, we instead now tag pages as dirty/writeback in the radix tree.
1401	*
1402	* All pagecache pages may be subject to I/O:
1403	* - inode pages may need to be read from disk,
1404	* - inode pages which have been modified and are MAP_SHARED may need
1405	* to be written back to the inode on disk,
1406	* - anonymous pages (including MAP_PRIVATE file mappings) which have been
1407	* modified may need to be swapped out to swap space and (later) to be read
1408	* back into memory.
1409	*/
1410
1411	#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
1412	DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
1413
1414	bool __put_devmap_managed_page_refs(struct page *page, int refs);
1415	static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
1416	{
1417	if (!static_branch_unlikely(&devmap_managed_key))
1418	return false;
1419	if (!is_zone_device_page(page))
1420	return false;
1421	return __put_devmap_managed_page_refs(page, refs);
1422	}
1423	#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
1424	static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
1425	{
1426	return false;
1427	}
1428	#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
1429
1430	static inline bool put_devmap_managed_page(struct page *page)
1431	{
1432	return put_devmap_managed_page_refs(page, refs: 1);
1433	}
1434
1435	/* 127: arbitrary random number, small enough to assemble well */
1436	#define folio_ref_zero_or_close_to_overflow(folio) \
1437	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
1438
1439	/**
1440	* folio_get - Increment the reference count on a folio.
1441	* @folio: The folio.
1442	*
1443	* Context: May be called in any context, as long as you know that
1444	* you have a refcount on the folio. If you do not already have one,
1445	* folio_try_get() may be the right interface for you to use.
1446	*/
1447	static inline void folio_get(struct folio *folio)
1448	{
1449	VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio);
1450	folio_ref_inc(folio);
1451	}
1452
1453	static inline void get_page(struct page *page)
1454	{
1455	folio_get(page_folio(page));
1456	}
1457
1458	static inline __must_check bool try_get_page(struct page *page)
1459	{
1460	page = compound_head(page);
1461	if (WARN_ON_ONCE(page_ref_count(page) <= 0))
1462	return false;
1463	page_ref_inc(page);
1464	return true;
1465	}
1466
1467	/**
1468	* folio_put - Decrement the reference count on a folio.
1469	* @folio: The folio.
1470	*
1471	* If the folio's reference count reaches zero, the memory will be
1472	* released back to the page allocator and may be used by another
1473	* allocation immediately. Do not access the memory or the struct folio
1474	* after calling folio_put() unless you can be sure that it wasn't the
1475	* last reference.
1476	*
1477	* Context: May be called in process or interrupt context, but not in NMI
1478	* context. May be called while holding a spinlock.
1479	*/
1480	static inline void folio_put(struct folio *folio)
1481	{
1482	if (folio_put_testzero(folio))
1483	__folio_put(folio);
1484	}
1485
1486	/**
1487	* folio_put_refs - Reduce the reference count on a folio.
1488	* @folio: The folio.
1489	* @refs: The amount to subtract from the folio's reference count.
1490	*
1491	* If the folio's reference count reaches zero, the memory will be
1492	* released back to the page allocator and may be used by another
1493	* allocation immediately. Do not access the memory or the struct folio
1494	* after calling folio_put_refs() unless you can be sure that these weren't
1495	* the last references.
1496	*
1497	* Context: May be called in process or interrupt context, but not in NMI
1498	* context. May be called while holding a spinlock.
1499	*/
1500	static inline void folio_put_refs(struct folio *folio, int refs)
1501	{
1502	if (folio_ref_sub_and_test(folio, nr: refs))
1503	__folio_put(folio);
1504	}
1505
1506	/*
1507	* union release_pages_arg - an array of pages or folios
1508	*
1509	* release_pages() releases a simple array of multiple pages, and
1510	* accepts various different forms of said page array: either
1511	* a regular old boring array of pages, an array of folios, or
1512	* an array of encoded page pointers.
1513	*
1514	* The transparent union syntax for this kind of "any of these
1515	* argument types" is all kinds of ugly, so look away.
1516	*/
1517	typedef union {
1518	struct page **pages;
1519	struct folio **folios;
1520	struct encoded_page **encoded_pages;
1521	} release_pages_arg __attribute__ ((__transparent_union__));
1522
1523	void release_pages(release_pages_arg, int nr);
1524
1525	/**
1526	* folios_put - Decrement the reference count on an array of folios.
1527	* @folios: The folios.
1528	* @nr: How many folios there are.
1529	*
1530	* Like folio_put(), but for an array of folios. This is more efficient
1531	* than writing the loop yourself as it will optimise the locks which
1532	* need to be taken if the folios are freed.
1533	*
1534	* Context: May be called in process or interrupt context, but not in NMI
1535	* context. May be called while holding a spinlock.
1536	*/
1537	static inline void folios_put(struct folio **folios, unsigned int nr)
1538	{
1539	release_pages(folios, nr);
1540	}
1541
1542	static inline void put_page(struct page *page)
1543	{
1544	struct folio *folio = page_folio(page);
1545
1546	/*
1547	* For some devmap managed pages we need to catch refcount transition
1548	* from 2 to 1:
1549	*/
1550	if (put_devmap_managed_page(page: &folio->page))
1551	return;
1552	folio_put(folio);
1553	}
1554
1555	/*
1556	* GUP_PIN_COUNTING_BIAS, and the associated functions that use it, overload
1557	* the page's refcount so that two separate items are tracked: the original page
1558	* reference count, and also a new count of how many pin_user_pages() calls were
1559	* made against the page. ("gup-pinned" is another term for the latter).
1560	*
1561	* With this scheme, pin_user_pages() becomes special: such pages are marked as
1562	* distinct from normal pages. As such, the unpin_user_page() call (and its
1563	* variants) must be used in order to release gup-pinned pages.
1564	*
1565	* Choice of value:
1566	*
1567	* By making GUP_PIN_COUNTING_BIAS a power of two, debugging of page reference
1568	* counts with respect to pin_user_pages() and unpin_user_page() becomes
1569	* simpler, due to the fact that adding an even power of two to the page
1570	* refcount has the effect of using only the upper N bits, for the code that
1571	* counts up using the bias value. This means that the lower bits are left for
1572	* the exclusive use of the original code that increments and decrements by one
1573	* (or at least, by much smaller values than the bias value).
1574	*
1575	* Of course, once the lower bits overflow into the upper bits (and this is
1576	* OK, because subtraction recovers the original values), then visual inspection
1577	* no longer suffices to directly view the separate counts. However, for normal
1578	* applications that don't have huge page reference counts, this won't be an
1579	* issue.
1580	*
1581	* Locking: the lockless algorithm described in folio_try_get_rcu()
1582	* provides safe operation for get_user_pages(), page_mkclean() and
1583	* other calls that race to set up page table entries.
1584	*/
1585	#define GUP_PIN_COUNTING_BIAS (1U << 10)
1586
1587	void unpin_user_page(struct page *page);
1588	void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
1589	bool make_dirty);
1590	void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
1591	bool make_dirty);
1592	void unpin_user_pages(struct page **pages, unsigned long npages);
1593
1594	static inline bool is_cow_mapping(vm_flags_t flags)
1595	{
1596	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1597	}
1598
1599	#ifndef CONFIG_MMU
1600	static inline bool is_nommu_shared_mapping(vm_flags_t flags)
1601	{
1602	/*
1603	* NOMMU shared mappings are ordinary MAP_SHARED mappings and selected
1604	* R/O MAP_PRIVATE file mappings that are an effective R/O overlay of
1605	* a file mapping. R/O MAP_PRIVATE mappings might still modify
1606	* underlying memory if ptrace is active, so this is only possible if
1607	* ptrace does not apply. Note that there is no mprotect() to upgrade
1608	* write permissions later.
1609	*/
1610	return flags & (VM_MAYSHARE | VM_MAYOVERLAY);
1611	}
1612	#endif
1613
1614	#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
1615	#define SECTION_IN_PAGE_FLAGS
1616	#endif
1617
1618	/*
1619	* The identification function is mainly used by the buddy allocator for
1620	* determining if two pages could be buddies. We are not really identifying
1621	* the zone since we could be using the section number id if we do not have
1622	* node id available in page flags.
1623	* We only guarantee that it will return the same value for two combinable
1624	* pages in a zone.
1625	*/
1626	static inline int page_zone_id(struct page *page)
1627	{
1628	return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
1629	}
1630
1631	#ifdef NODE_NOT_IN_PAGE_FLAGS
1632	extern int page_to_nid(const struct page *page);
1633	#else
1634	static inline int page_to_nid(const struct page *page)
1635	{
1636	struct page *p = (struct page *)page;
1637
1638	return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK;
1639	}
1640	#endif
1641
1642	static inline int folio_nid(const struct folio *folio)
1643	{
1644	return page_to_nid(page: &folio->page);
1645	}
1646
1647	#ifdef CONFIG_NUMA_BALANCING
1648	/* page access time bits needs to hold at least 4 seconds */
1649	#define PAGE_ACCESS_TIME_MIN_BITS 12
1650	#if LAST_CPUPID_SHIFT < PAGE_ACCESS_TIME_MIN_BITS
1651	#define PAGE_ACCESS_TIME_BUCKETS \
1652	(PAGE_ACCESS_TIME_MIN_BITS - LAST_CPUPID_SHIFT)
1653	#else
1654	#define PAGE_ACCESS_TIME_BUCKETS 0
1655	#endif
1656
1657	#define PAGE_ACCESS_TIME_MASK \
1658	(LAST_CPUPID_MASK << PAGE_ACCESS_TIME_BUCKETS)
1659
1660	static inline int cpu_pid_to_cpupid(int cpu, int pid)
1661	{
1662	return ((cpu & LAST__CPU_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
1663	}
1664
1665	static inline int cpupid_to_pid(int cpupid)
1666	{
1667	return cpupid & LAST__PID_MASK;
1668	}
1669
1670	static inline int cpupid_to_cpu(int cpupid)
1671	{
1672	return (cpupid >> LAST__PID_SHIFT) & LAST__CPU_MASK;
1673	}
1674
1675	static inline int cpupid_to_nid(int cpupid)
1676	{
1677	return cpu_to_node(cpu: cpupid_to_cpu(cpupid));
1678	}
1679
1680	static inline bool cpupid_pid_unset(int cpupid)
1681	{
1682	return cpupid_to_pid(cpupid) == (-1 & LAST__PID_MASK);
1683	}
1684
1685	static inline bool cpupid_cpu_unset(int cpupid)
1686	{
1687	return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
1688	}
1689
1690	static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
1691	{
1692	return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
1693	}
1694
1695	#define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
1696	#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
1697	static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
1698	{
1699	return xchg(&folio->_last_cpupid, cpupid & LAST_CPUPID_MASK);
1700	}
1701
1702	static inline int folio_last_cpupid(struct folio *folio)
1703	{
1704	return folio->_last_cpupid;
1705	}
1706	static inline void page_cpupid_reset_last(struct page *page)
1707	{
1708	page->_last_cpupid = -1 & LAST_CPUPID_MASK;
1709	}
1710	#else
1711	static inline int folio_last_cpupid(struct folio *folio)
1712	{
1713	return (folio->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
1714	}
1715
1716	int folio_xchg_last_cpupid(struct folio *folio, int cpupid);
1717
1718	static inline void page_cpupid_reset_last(struct page *page)
1719	{
1720	page->flags |= LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT;
1721	}
1722	#endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
1723
1724	static inline int folio_xchg_access_time(struct folio *folio, int time)
1725	{
1726	int last_time;
1727
1728	last_time = folio_xchg_last_cpupid(folio,
1729	time >> PAGE_ACCESS_TIME_BUCKETS);
1730	return last_time << PAGE_ACCESS_TIME_BUCKETS;
1731	}
1732
1733	static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
1734	{
1735	unsigned int pid_bit;
1736
1737	pid_bit = hash_32(current->pid, ilog2(BITS_PER_LONG));
1738	if (vma->numab_state && !test_bit(pid_bit, &vma->numab_state->pids_active[1])) {
1739	__set_bit(pid_bit, &vma->numab_state->pids_active[1]);
1740	}
1741	}
1742	#else /* !CONFIG_NUMA_BALANCING */
1743	static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
1744	{
1745	return folio_nid(folio); /* XXX */
1746	}
1747
1748	static inline int folio_xchg_access_time(struct folio *folio, int time)
1749	{
1750	return 0;
1751	}
1752
1753	static inline int folio_last_cpupid(struct folio *folio)
1754	{
1755	return folio_nid(folio); /* XXX */
1756	}
1757
1758	static inline int cpupid_to_nid(int cpupid)
1759	{
1760	return -1;
1761	}
1762
1763	static inline int cpupid_to_pid(int cpupid)
1764	{
1765	return -1;
1766	}
1767
1768	static inline int cpupid_to_cpu(int cpupid)
1769	{
1770	return -1;
1771	}
1772
1773	static inline int cpu_pid_to_cpupid(int nid, int pid)
1774	{
1775	return -1;
1776	}
1777
1778	static inline bool cpupid_pid_unset(int cpupid)
1779	{
1780	return true;
1781	}
1782
1783	static inline void page_cpupid_reset_last(struct page *page)
1784	{
1785	}
1786
1787	static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
1788	{
1789	return false;
1790	}
1791
1792	static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
1793	{
1794	}
1795	#endif /* CONFIG_NUMA_BALANCING */
1796
1797	#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
1798
1799	/*
1800	* KASAN per-page tags are stored xor'ed with 0xff. This allows to avoid
1801	* setting tags for all pages to native kernel tag value 0xff, as the default
1802	* value 0x00 maps to 0xff.
1803	*/
1804
1805	static inline u8 page_kasan_tag(const struct page *page)
1806	{
1807	u8 tag = 0xff;
1808
1809	if (kasan_enabled()) {
1810	tag = (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
1811	tag ^= 0xff;
1812	}
1813
1814	return tag;
1815	}
1816
1817	static inline void page_kasan_tag_set(struct page *page, u8 tag)
1818	{
1819	unsigned long old_flags, flags;
1820
1821	if (!kasan_enabled())
1822	return;
1823
1824	tag ^= 0xff;
1825	old_flags = READ_ONCE(page->flags);
1826	do {
1827	flags = old_flags;
1828	flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
1829	flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
1830	} while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
1831	}
1832
1833	static inline void page_kasan_tag_reset(struct page *page)
1834	{
1835	if (kasan_enabled())
1836	page_kasan_tag_set(page, 0xff);
1837	}
1838
1839	#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
1840
1841	static inline u8 page_kasan_tag(const struct page *page)
1842	{
1843	return 0xff;
1844	}
1845
1846	static inline void page_kasan_tag_set(struct page *page, u8 tag) { }
1847	static inline void page_kasan_tag_reset(struct page *page) { }
1848
1849	#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
1850
1851	static inline struct zone *page_zone(const struct page *page)
1852	{
1853	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
1854	}
1855
1856	static inline pg_data_t *page_pgdat(const struct page *page)
1857	{
1858	return NODE_DATA(page_to_nid(page));
1859	}
1860
1861	static inline struct zone *folio_zone(const struct folio *folio)
1862	{
1863	return page_zone(page: &folio->page);
1864	}
1865
1866	static inline pg_data_t *folio_pgdat(const struct folio *folio)
1867	{
1868	return page_pgdat(page: &folio->page);
1869	}
1870
1871	#ifdef SECTION_IN_PAGE_FLAGS
1872	static inline void set_page_section(struct page *page, unsigned long section)
1873	{
1874	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
1875	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
1876	}
1877
1878	static inline unsigned long page_to_section(const struct page *page)
1879	{
1880	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
1881	}
1882	#endif
1883
1884	/**
1885	* folio_pfn - Return the Page Frame Number of a folio.
1886	* @folio: The folio.
1887	*
1888	* A folio may contain multiple pages. The pages have consecutive
1889	* Page Frame Numbers.
1890	*
1891	* Return: The Page Frame Number of the first page in the folio.
1892	*/
1893	static inline unsigned long folio_pfn(struct folio *folio)
1894	{
1895	return page_to_pfn(&folio->page);
1896	}
1897
1898	static inline struct folio *pfn_folio(unsigned long pfn)
1899	{
1900	return page_folio(pfn_to_page(pfn));
1901	}
1902
1903	/**
1904	* folio_maybe_dma_pinned - Report if a folio may be pinned for DMA.
1905	* @folio: The folio.
1906	*
1907	* This function checks if a folio has been pinned via a call to
1908	* a function in the pin_user_pages() family.
1909	*
1910	* For small folios, the return value is partially fuzzy: false is not fuzzy,
1911	* because it means "definitely not pinned for DMA", but true means "probably
1912	* pinned for DMA, but possibly a false positive due to having at least
1913	* GUP_PIN_COUNTING_BIAS worth of normal folio references".
1914	*
1915	* False positives are OK, because: a) it's unlikely for a folio to
1916	* get that many refcounts, and b) all the callers of this routine are
1917	* expected to be able to deal gracefully with a false positive.
1918	*
1919	* For large folios, the result will be exactly correct. That's because
1920	* we have more tracking data available: the _pincount field is used
1921	* instead of the GUP_PIN_COUNTING_BIAS scheme.
1922	*
1923	* For more information, please see Documentation/core-api/pin_user_pages.rst.
1924	*
1925	* Return: True, if it is likely that the page has been "dma-pinned".
1926	* False, if the page is definitely not dma-pinned.
1927	*/
1928	static inline bool folio_maybe_dma_pinned(struct folio *folio)
1929	{
1930	if (folio_test_large(folio))
1931	return atomic_read(v: &folio->_pincount) > 0;
1932
1933	/*
1934	* folio_ref_count() is signed. If that refcount overflows, then
1935	* folio_ref_count() returns a negative value, and callers will avoid
1936	* further incrementing the refcount.
1937	*
1938	* Here, for that overflow case, use the sign bit to count a little
1939	* bit higher via unsigned math, and thus still get an accurate result.
1940	*/
1941	return ((unsigned int)folio_ref_count(folio)) >=
1942	GUP_PIN_COUNTING_BIAS;
1943	}
1944
1945	static inline bool page_maybe_dma_pinned(struct page *page)
1946	{
1947	return folio_maybe_dma_pinned(page_folio(page));
1948	}
1949
1950	/*
1951	* This should most likely only be called during fork() to see whether we
1952	* should break the cow immediately for an anon page on the src mm.
1953	*
1954	* The caller has to hold the PT lock and the vma->vm_mm->->write_protect_seq.
1955	*/
1956	static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma,
1957	struct page *page)
1958	{
1959	VM_BUG_ON(!(raw_read_seqcount(&vma->vm_mm->write_protect_seq) & 1));
1960
1961	if (!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags))
1962	return false;
1963
1964	return page_maybe_dma_pinned(page);
1965	}
1966
1967	/**
1968	* is_zero_page - Query if a page is a zero page
1969	* @page: The page to query
1970	*
1971	* This returns true if @page is one of the permanent zero pages.
1972	*/
1973	static inline bool is_zero_page(const struct page *page)
1974	{
1975	return is_zero_pfn(page_to_pfn(page));
1976	}
1977
1978	/**
1979	* is_zero_folio - Query if a folio is a zero page
1980	* @folio: The folio to query
1981	*
1982	* This returns true if @folio is one of the permanent zero pages.
1983	*/
1984	static inline bool is_zero_folio(const struct folio *folio)
1985	{
1986	return is_zero_page(page: &folio->page);
1987	}
1988
1989	/* MIGRATE_CMA and ZONE_MOVABLE do not allow pin folios */
1990	#ifdef CONFIG_MIGRATION
1991	static inline bool folio_is_longterm_pinnable(struct folio *folio)
1992	{
1993	#ifdef CONFIG_CMA
1994	int mt = folio_migratetype(folio);
1995
1996	if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
1997	return false;
1998	#endif
1999	/* The zero page can be "pinned" but gets special handling. */
2000	if (is_zero_folio(folio))
2001	return true;
2002
2003	/* Coherent device memory must always allow eviction. */
2004	if (folio_is_device_coherent(folio))
2005	return false;
2006
2007	/* Otherwise, non-movable zone folios can be pinned. */
2008	return !folio_is_zone_movable(folio);
2009
2010	}
2011	#else
2012	static inline bool folio_is_longterm_pinnable(struct folio *folio)
2013	{
2014	return true;
2015	}
2016	#endif
2017
2018	static inline void set_page_zone(struct page *page, enum zone_type zone)
2019	{
2020	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
2021	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
2022	}
2023
2024	static inline void set_page_node(struct page *page, unsigned long node)
2025	{
2026	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
2027	page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
2028	}
2029
2030	static inline void set_page_links(struct page *page, enum zone_type zone,
2031	unsigned long node, unsigned long pfn)
2032	{
2033	set_page_zone(page, zone);
2034	set_page_node(page, node);
2035	#ifdef SECTION_IN_PAGE_FLAGS
2036	set_page_section(page, pfn_to_section_nr(pfn));
2037	#endif
2038	}
2039
2040	/**
2041	* folio_nr_pages - The number of pages in the folio.
2042	* @folio: The folio.
2043	*
2044	* Return: A positive power of two.
2045	*/
2046	static inline long folio_nr_pages(struct folio *folio)
2047	{
2048	if (!folio_test_large(folio))
2049	return 1;
2050	#ifdef CONFIG_64BIT
2051	return folio->_folio_nr_pages;
2052	#else
2053	return 1L << (folio->_flags_1 & 0xff);
2054	#endif
2055	}
2056
2057	/*
2058	* compound_nr() returns the number of pages in this potentially compound
2059	* page. compound_nr() can be called on a tail page, and is defined to
2060	* return 1 in that case.
2061	*/
2062	static inline unsigned long compound_nr(struct page *page)
2063	{
2064	struct folio *folio = (struct folio *)page;
2065
2066	if (!test_bit(PG_head, &folio->flags))
2067	return 1;
2068	#ifdef CONFIG_64BIT
2069	return folio->_folio_nr_pages;
2070	#else
2071	return 1L << (folio->_flags_1 & 0xff);
2072	#endif
2073	}
2074
2075	/**
2076	* thp_nr_pages - The number of regular pages in this huge page.
2077	* @page: The head page of a huge page.
2078	*/
2079	static inline int thp_nr_pages(struct page *page)
2080	{
2081	return folio_nr_pages(folio: (struct folio *)page);
2082	}
2083
2084	/**
2085	* folio_next - Move to the next physical folio.
2086	* @folio: The folio we're currently operating on.
2087	*
2088	* If you have physically contiguous memory which may span more than
2089	* one folio (eg a &struct bio_vec), use this function to move from one
2090	* folio to the next. Do not use it if the memory is only virtually
2091	* contiguous as the folios are almost certainly not adjacent to each
2092	* other. This is the folio equivalent to writing ``page++``.
2093	*
2094	* Context: We assume that the folios are refcounted and/or locked at a
2095	* higher level and do not adjust the reference counts.
2096	* Return: The next struct folio.
2097	*/
2098	static inline struct folio *folio_next(struct folio *folio)
2099	{
2100	return (struct folio *)folio_page(folio, folio_nr_pages(folio));
2101	}
2102
2103	/**
2104	* folio_shift - The size of the memory described by this folio.
2105	* @folio: The folio.
2106	*
2107	* A folio represents a number of bytes which is a power-of-two in size.
2108	* This function tells you which power-of-two the folio is. See also
2109	* folio_size() and folio_order().
2110	*
2111	* Context: The caller should have a reference on the folio to prevent
2112	* it from being split. It is not necessary for the folio to be locked.
2113	* Return: The base-2 logarithm of the size of this folio.
2114	*/
2115	static inline unsigned int folio_shift(struct folio *folio)
2116	{
2117	return PAGE_SHIFT + folio_order(folio);
2118	}
2119
2120	/**
2121	* folio_size - The number of bytes in a folio.
2122	* @folio: The folio.
2123	*
2124	* Context: The caller should have a reference on the folio to prevent
2125	* it from being split. It is not necessary for the folio to be locked.
2126	* Return: The number of bytes in this folio.
2127	*/
2128	static inline size_t folio_size(struct folio *folio)
2129	{
2130	return PAGE_SIZE << folio_order(folio);
2131	}
2132
2133	/**
2134	* folio_estimated_sharers - Estimate the number of sharers of a folio.
2135	* @folio: The folio.
2136	*
2137	* folio_estimated_sharers() aims to serve as a function to efficiently
2138	* estimate the number of processes sharing a folio. This is done by
2139	* looking at the precise mapcount of the first subpage in the folio, and
2140	* assuming the other subpages are the same. This may not be true for large
2141	* folios. If you want exact mapcounts for exact calculations, look at
2142	* page_mapcount() or folio_total_mapcount().
2143	*
2144	* Return: The estimated number of processes sharing a folio.
2145	*/
2146	static inline int folio_estimated_sharers(struct folio *folio)
2147	{
2148	return page_mapcount(folio_page(folio, 0));
2149	}
2150
2151	#ifndef HAVE_ARCH_MAKE_PAGE_ACCESSIBLE
2152	static inline int arch_make_page_accessible(struct page *page)
2153	{
2154	return 0;
2155	}
2156	#endif
2157
2158	#ifndef HAVE_ARCH_MAKE_FOLIO_ACCESSIBLE
2159	static inline int arch_make_folio_accessible(struct folio *folio)
2160	{
2161	int ret;
2162	long i, nr = folio_nr_pages(folio);
2163
2164	for (i = 0; i < nr; i++) {
2165	ret = arch_make_page_accessible(folio_page(folio, i));
2166	if (ret)
2167	break;
2168	}
2169
2170	return ret;
2171	}
2172	#endif
2173
2174	/*
2175	* Some inline functions in vmstat.h depend on page_zone()
2176	*/
2177	#include <linux/vmstat.h>
2178
2179	static __always_inline void *lowmem_page_address(const struct page *page)
2180	{
2181	return page_to_virt(page);
2182	}
2183
2184	#if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
2185	#define HASHED_PAGE_VIRTUAL
2186	#endif
2187
2188	#if defined(WANT_PAGE_VIRTUAL)
2189	static inline void *page_address(const struct page *page)
2190	{
2191	return page->virtual;
2192	}
2193	static inline void set_page_address(struct page *page, void *address)
2194	{
2195	page->virtual = address;
2196	}
2197	#define page_address_init() do { } while(0)
2198	#endif
2199
2200	#if defined(HASHED_PAGE_VIRTUAL)
2201	void *page_address(const struct page *page);
2202	void set_page_address(struct page *page, void *virtual);
2203	void page_address_init(void);
2204	#endif
2205
2206	#if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
2207	#define page_address(page) lowmem_page_address(page)
2208	#define set_page_address(page, address) do { } while(0)
2209	#define page_address_init() do { } while(0)
2210	#endif
2211
2212	static inline void *folio_address(const struct folio *folio)
2213	{
2214	return page_address(&folio->page);
2215	}
2216
2217	extern pgoff_t __page_file_index(struct page *page);
2218
2219	/*
2220	* Return the pagecache index of the passed page. Regular pagecache pages
2221	* use ->index whereas swapcache pages use swp_offset(->private)
2222	*/
2223	static inline pgoff_t page_index(struct page *page)
2224	{
2225	if (unlikely(PageSwapCache(page)))
2226	return __page_file_index(page);
2227	return page->index;
2228	}
2229
2230	/*
2231	* Return true only if the page has been allocated with
2232	* ALLOC_NO_WATERMARKS and the low watermark was not
2233	* met implying that the system is under some pressure.
2234	*/
2235	static inline bool page_is_pfmemalloc(const struct page *page)
2236	{
2237	/*
2238	* lru.next has bit 1 set if the page is allocated from the
2239	* pfmemalloc reserves. Callers may simply overwrite it if
2240	* they do not need to preserve that information.
2241	*/
2242	return (uintptr_t)page->lru.next & BIT(1);
2243	}
2244
2245	/*
2246	* Return true only if the folio has been allocated with
2247	* ALLOC_NO_WATERMARKS and the low watermark was not
2248	* met implying that the system is under some pressure.
2249	*/
2250	static inline bool folio_is_pfmemalloc(const struct folio *folio)
2251	{
2252	/*
2253	* lru.next has bit 1 set if the page is allocated from the
2254	* pfmemalloc reserves. Callers may simply overwrite it if
2255	* they do not need to preserve that information.
2256	*/
2257	return (uintptr_t)folio->lru.next & BIT(1);
2258	}
2259
2260	/*
2261	* Only to be called by the page allocator on a freshly allocated
2262	* page.
2263	*/
2264	static inline void set_page_pfmemalloc(struct page *page)
2265	{
2266	page->lru.next = (void *)BIT(1);
2267	}
2268
2269	static inline void clear_page_pfmemalloc(struct page *page)
2270	{
2271	page->lru.next = NULL;
2272	}
2273
2274	/*
2275	* Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
2276	*/
2277	extern void pagefault_out_of_memory(void);
2278
2279	#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
2280	#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1))
2281	#define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))
2282
2283	/*
2284	* Parameter block passed down to zap_pte_range in exceptional cases.
2285	*/
2286	struct zap_details {
2287	struct folio *single_folio; /* Locked folio to be unmapped */
2288	bool even_cows; /* Zap COWed private pages too? */
2289	zap_flags_t zap_flags; /* Extra flags for zapping */
2290	};
2291
2292	/*
2293	* Whether to drop the pte markers, for example, the uffd-wp information for
2294	* file-backed memory. This should only be specified when we will completely
2295	* drop the page in the mm, either by truncation or unmapping of the vma. By
2296	* default, the flag is not set.
2297	*/
2298	#define ZAP_FLAG_DROP_MARKER ((__force zap_flags_t) BIT(0))
2299	/* Set in unmap_vmas() to indicate a final unmap call. Only used by hugetlb */
2300	#define ZAP_FLAG_UNMAP ((__force zap_flags_t) BIT(1))
2301
2302	#ifdef CONFIG_SCHED_MM_CID
2303	void sched_mm_cid_before_execve(struct task_struct *t);
2304	void sched_mm_cid_after_execve(struct task_struct *t);
2305	void sched_mm_cid_fork(struct task_struct *t);
2306	void sched_mm_cid_exit_signals(struct task_struct *t);
2307	static inline int task_mm_cid(struct task_struct *t)
2308	{
2309	return t->mm_cid;
2310	}
2311	#else
2312	static inline void sched_mm_cid_before_execve(struct task_struct *t) { }
2313	static inline void sched_mm_cid_after_execve(struct task_struct *t) { }
2314	static inline void sched_mm_cid_fork(struct task_struct *t) { }
2315	static inline void sched_mm_cid_exit_signals(struct task_struct *t) { }
2316	static inline int task_mm_cid(struct task_struct *t)
2317	{
2318	/*
2319	* Use the processor id as a fall-back when the mm cid feature is
2320	* disabled. This provides functional per-cpu data structure accesses
2321	* in user-space, althrough it won't provide the memory usage benefits.
2322	*/
2323	return raw_smp_processor_id();
2324	}
2325	#endif
2326
2327	#ifdef CONFIG_MMU
2328	extern bool can_do_mlock(void);
2329	#else
2330	static inline bool can_do_mlock(void) { return false; }
2331	#endif
2332	extern int user_shm_lock(size_t, struct ucounts *);
2333	extern void user_shm_unlock(size_t, struct ucounts *);
2334
2335	struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr,
2336	pte_t pte);
2337	struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
2338	pte_t pte);
2339	struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma,
2340	unsigned long addr, pmd_t pmd);
2341	struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
2342	pmd_t pmd);
2343
2344	void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
2345	unsigned long size);
2346	void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
2347	unsigned long size, struct zap_details *details);
2348	static inline void zap_vma_pages(struct vm_area_struct *vma)
2349	{
2350	zap_page_range_single(vma, address: vma->vm_start,
2351	size: vma->vm_end - vma->vm_start, NULL);
2352	}
2353	void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
2354	struct vm_area_struct *start_vma, unsigned long start,
2355	unsigned long end, unsigned long tree_end, bool mm_wr_locked);
2356
2357	struct mmu_notifier_range;
2358
2359	void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
2360	unsigned long end, unsigned long floor, unsigned long ceiling);
2361	int
2362	copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma);
2363	int follow_pte(struct mm_struct *mm, unsigned long address,
2364	pte_t **ptepp, spinlock_t **ptlp);
2365	int follow_pfn(struct vm_area_struct *vma, unsigned long address,
2366	unsigned long *pfn);
2367	int follow_phys(struct vm_area_struct *vma, unsigned long address,
2368	unsigned int flags, unsigned long *prot, resource_size_t *phys);
2369	int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
2370	void *buf, int len, int write);
2371
2372	extern void truncate_pagecache(struct inode *inode, loff_t new);
2373	extern void truncate_setsize(struct inode *inode, loff_t newsize);
2374	void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);
2375	void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
2376	int generic_error_remove_page(struct address_space *mapping, struct page *page);
2377
2378	struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
2379	unsigned long address, struct pt_regs *regs);
2380
2381	#ifdef CONFIG_MMU
2382	extern vm_fault_t handle_mm_fault(struct vm_area_struct *vma,
2383	unsigned long address, unsigned int flags,
2384	struct pt_regs *regs);
2385	extern int fixup_user_fault(struct mm_struct *mm,
2386	unsigned long address, unsigned int fault_flags,
2387	bool *unlocked);
2388	void unmap_mapping_pages(struct address_space *mapping,
2389	pgoff_t start, pgoff_t nr, bool even_cows);
2390	void unmap_mapping_range(struct address_space *mapping,
2391	loff_t const holebegin, loff_t const holelen, int even_cows);
2392	#else
2393	static inline vm_fault_t handle_mm_fault(struct vm_area_struct *vma,
2394	unsigned long address, unsigned int flags,
2395	struct pt_regs *regs)
2396	{
2397	/* should never happen if there's no MMU */
2398	BUG();
2399	return VM_FAULT_SIGBUS;
2400	}
2401	static inline int fixup_user_fault(struct mm_struct *mm, unsigned long address,
2402	unsigned int fault_flags, bool *unlocked)
2403	{
2404	/* should never happen if there's no MMU */
2405	BUG();
2406	return -EFAULT;
2407	}
2408	static inline void unmap_mapping_pages(struct address_space *mapping,
2409	pgoff_t start, pgoff_t nr, bool even_cows) { }
2410	static inline void unmap_mapping_range(struct address_space *mapping,
2411	loff_t const holebegin, loff_t const holelen, int even_cows) { }
2412	#endif
2413
2414	static inline void unmap_shared_mapping_range(struct address_space *mapping,
2415	loff_t const holebegin, loff_t const holelen)
2416	{
2417	unmap_mapping_range(mapping, holebegin, holelen, even_cows: 0);
2418	}
2419
2420	static inline struct vm_area_struct *vma_lookup(struct mm_struct *mm,
2421	unsigned long addr);
2422
2423	extern int access_process_vm(struct task_struct *tsk, unsigned long addr,
2424	void *buf, int len, unsigned int gup_flags);
2425	extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2426	void *buf, int len, unsigned int gup_flags);
2427
2428	long get_user_pages_remote(struct mm_struct *mm,
2429	unsigned long start, unsigned long nr_pages,
2430	unsigned int gup_flags, struct page **pages,
2431	int *locked);
2432	long pin_user_pages_remote(struct mm_struct *mm,
2433	unsigned long start, unsigned long nr_pages,
2434	unsigned int gup_flags, struct page **pages,
2435	int *locked);
2436
2437	/*
2438	* Retrieves a single page alongside its VMA. Does not support FOLL_NOWAIT.
2439	*/
2440	static inline struct page *get_user_page_vma_remote(struct mm_struct *mm,
2441	unsigned long addr,
2442	int gup_flags,
2443	struct vm_area_struct **vmap)
2444	{
2445	struct page *page;
2446	struct vm_area_struct *vma;
2447	int got;
2448
2449	if (WARN_ON_ONCE(unlikely(gup_flags & FOLL_NOWAIT)))
2450	return ERR_PTR(error: -EINVAL);
2451
2452	got = get_user_pages_remote(mm, start: addr, nr_pages: 1, gup_flags, pages: &page, NULL);
2453
2454	if (got < 0)
2455	return ERR_PTR(error: got);
2456
2457	vma = vma_lookup(mm, addr);
2458	if (WARN_ON_ONCE(!vma)) {
2459	put_page(page);
2460	return ERR_PTR(error: -EINVAL);
2461	}
2462
2463	*vmap = vma;
2464	return page;
2465	}
2466
2467	long get_user_pages(unsigned long start, unsigned long nr_pages,
2468	unsigned int gup_flags, struct page **pages);
2469	long pin_user_pages(unsigned long start, unsigned long nr_pages,
2470	unsigned int gup_flags, struct page **pages);
2471	long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
2472	struct page **pages, unsigned int gup_flags);
2473	long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
2474	struct page **pages, unsigned int gup_flags);
2475
2476	int get_user_pages_fast(unsigned long start, int nr_pages,
2477	unsigned int gup_flags, struct page **pages);
2478	int pin_user_pages_fast(unsigned long start, int nr_pages,
2479	unsigned int gup_flags, struct page **pages);
2480	void folio_add_pin(struct folio *folio);
2481
2482	int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc);
2483	int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
2484	struct task_struct *task, bool bypass_rlim);
2485
2486	struct kvec;
2487	struct page *get_dump_page(unsigned long addr);
2488
2489	bool folio_mark_dirty(struct folio *folio);
2490	bool set_page_dirty(struct page *page);
2491	int set_page_dirty_lock(struct page *page);
2492
2493	int get_cmdline(struct task_struct *task, char *buffer, int buflen);
2494
2495	extern unsigned long move_page_tables(struct vm_area_struct *vma,
2496	unsigned long old_addr, struct vm_area_struct *new_vma,
2497	unsigned long new_addr, unsigned long len,
2498	bool need_rmap_locks, bool for_stack);
2499
2500	/*
2501	* Flags used by change_protection(). For now we make it a bitmap so
2502	* that we can pass in multiple flags just like parameters. However
2503	* for now all the callers are only use one of the flags at the same
2504	* time.
2505	*/
2506	/*
2507	* Whether we should manually check if we can map individual PTEs writable,
2508	* because something (e.g., COW, uffd-wp) blocks that from happening for all
2509	* PTEs automatically in a writable mapping.
2510	*/
2511	#define MM_CP_TRY_CHANGE_WRITABLE (1UL << 0)
2512	/* Whether this protection change is for NUMA hints */
2513	#define MM_CP_PROT_NUMA (1UL << 1)
2514	/* Whether this change is for write protecting */
2515	#define MM_CP_UFFD_WP (1UL << 2) /* do wp */
2516	#define MM_CP_UFFD_WP_RESOLVE (1UL << 3) /* Resolve wp */
2517	#define MM_CP_UFFD_WP_ALL (MM_CP_UFFD_WP | \
2518	MM_CP_UFFD_WP_RESOLVE)
2519
2520	bool vma_needs_dirty_tracking(struct vm_area_struct *vma);
2521	int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot);
2522	static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma)
2523	{
2524	/*
2525	* We want to check manually if we can change individual PTEs writable
2526	* if we can't do that automatically for all PTEs in a mapping. For
2527	* private mappings, that's always the case when we have write
2528	* permissions as we properly have to handle COW.
2529	*/
2530	if (vma->vm_flags & VM_SHARED)
2531	return vma_wants_writenotify(vma, vm_page_prot: vma->vm_page_prot);
2532	return !!(vma->vm_flags & VM_WRITE);
2533
2534	}
2535	bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
2536	pte_t pte);
2537	extern long change_protection(struct mmu_gather *tlb,
2538	struct vm_area_struct *vma, unsigned long start,
2539	unsigned long end, unsigned long cp_flags);
2540	extern int mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
2541	struct vm_area_struct *vma, struct vm_area_struct **pprev,
2542	unsigned long start, unsigned long end, unsigned long newflags);
2543
2544	/*
2545	* doesn't attempt to fault and will return short.
2546	*/
2547	int get_user_pages_fast_only(unsigned long start, int nr_pages,
2548	unsigned int gup_flags, struct page **pages);
2549
2550	static inline bool get_user_page_fast_only(unsigned long addr,
2551	unsigned int gup_flags, struct page **pagep)
2552	{
2553	return get_user_pages_fast_only(start: addr, nr_pages: 1, gup_flags, pages: pagep) == 1;
2554	}
2555	/*
2556	* per-process(per-mm_struct) statistics.
2557	*/
2558	static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
2559	{
2560	return percpu_counter_read_positive(fbc: &mm->rss_stat[member]);
2561	}
2562
2563	void mm_trace_rss_stat(struct mm_struct *mm, int member);
2564
2565	static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
2566	{
2567	percpu_counter_add(fbc: &mm->rss_stat[member], amount: value);
2568
2569	mm_trace_rss_stat(mm, member);
2570	}
2571
2572	static inline void inc_mm_counter(struct mm_struct *mm, int member)
2573	{
2574	percpu_counter_inc(fbc: &mm->rss_stat[member]);
2575
2576	mm_trace_rss_stat(mm, member);
2577	}
2578
2579	static inline void dec_mm_counter(struct mm_struct *mm, int member)
2580	{
2581	percpu_counter_dec(fbc: &mm->rss_stat[member]);
2582
2583	mm_trace_rss_stat(mm, member);
2584	}
2585
2586	/* Optimized variant when page is already known not to be PageAnon */
2587	static inline int mm_counter_file(struct page *page)
2588	{
2589	if (PageSwapBacked(page))
2590	return MM_SHMEMPAGES;
2591	return MM_FILEPAGES;
2592	}
2593
2594	static inline int mm_counter(struct page *page)
2595	{
2596	if (PageAnon(page))
2597	return MM_ANONPAGES;
2598	return mm_counter_file(page);
2599	}
2600
2601	static inline unsigned long get_mm_rss(struct mm_struct *mm)
2602	{
2603	return get_mm_counter(mm, member: MM_FILEPAGES) +
2604	get_mm_counter(mm, member: MM_ANONPAGES) +
2605	get_mm_counter(mm, member: MM_SHMEMPAGES);
2606	}
2607
2608	static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
2609	{
2610	return max(mm->hiwater_rss, get_mm_rss(mm));
2611	}
2612
2613	static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
2614	{
2615	return max(mm->hiwater_vm, mm->total_vm);
2616	}
2617
2618	static inline void update_hiwater_rss(struct mm_struct *mm)
2619	{
2620	unsigned long _rss = get_mm_rss(mm);
2621
2622	if ((mm)->hiwater_rss < _rss)
2623	(mm)->hiwater_rss = _rss;
2624	}
2625
2626	static inline void update_hiwater_vm(struct mm_struct *mm)
2627	{
2628	if (mm->hiwater_vm < mm->total_vm)
2629	mm->hiwater_vm = mm->total_vm;
2630	}
2631
2632	static inline void reset_mm_hiwater_rss(struct mm_struct *mm)
2633	{
2634	mm->hiwater_rss = get_mm_rss(mm);
2635	}
2636
2637	static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
2638	struct mm_struct *mm)
2639	{
2640	unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
2641
2642	if (*maxrss < hiwater_rss)
2643	*maxrss = hiwater_rss;
2644	}
2645
2646	#ifndef CONFIG_ARCH_HAS_PTE_SPECIAL
2647	static inline int pte_special(pte_t pte)
2648	{
2649	return 0;
2650	}
2651
2652	static inline pte_t pte_mkspecial(pte_t pte)
2653	{
2654	return pte;
2655	}
2656	#endif
2657
2658	#ifndef CONFIG_ARCH_HAS_PTE_DEVMAP
2659	static inline int pte_devmap(pte_t pte)
2660	{
2661	return 0;
2662	}
2663	#endif
2664
2665	extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
2666	spinlock_t **ptl);
2667	static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
2668	spinlock_t **ptl)
2669	{
2670	pte_t *ptep;
2671	__cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
2672	return ptep;
2673	}
2674
2675	#ifdef __PAGETABLE_P4D_FOLDED
2676	static inline int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd,
2677	unsigned long address)
2678	{
2679	return 0;
2680	}
2681	#else
2682	int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
2683	#endif
2684
2685	#if defined(__PAGETABLE_PUD_FOLDED) || !defined(CONFIG_MMU)
2686	static inline int __pud_alloc(struct mm_struct *mm, p4d_t *p4d,
2687	unsigned long address)
2688	{
2689	return 0;
2690	}
2691	static inline void mm_inc_nr_puds(struct mm_struct *mm) {}
2692	static inline void mm_dec_nr_puds(struct mm_struct *mm) {}
2693
2694	#else
2695	int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address);
2696
2697	static inline void mm_inc_nr_puds(struct mm_struct *mm)
2698	{
2699	if (mm_pud_folded(mm))
2700	return;
2701	atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), v: &mm->pgtables_bytes);
2702	}
2703
2704	static inline void mm_dec_nr_puds(struct mm_struct *mm)
2705	{
2706	if (mm_pud_folded(mm))
2707	return;
2708	atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), v: &mm->pgtables_bytes);
2709	}
2710	#endif
2711
2712	#if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
2713	static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
2714	unsigned long address)
2715	{
2716	return 0;
2717	}
2718
2719	static inline void mm_inc_nr_pmds(struct mm_struct *mm) {}
2720	static inline void mm_dec_nr_pmds(struct mm_struct *mm) {}
2721
2722	#else
2723	int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
2724
2725	static inline void mm_inc_nr_pmds(struct mm_struct *mm)
2726	{
2727	if (mm_pmd_folded(mm))
2728	return;
2729	atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), v: &mm->pgtables_bytes);
2730	}
2731
2732	static inline void mm_dec_nr_pmds(struct mm_struct *mm)
2733	{
2734	if (mm_pmd_folded(mm))
2735	return;
2736	atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), v: &mm->pgtables_bytes);
2737	}
2738	#endif
2739
2740	#ifdef CONFIG_MMU
2741	static inline void mm_pgtables_bytes_init(struct mm_struct *mm)
2742	{
2743	atomic_long_set(v: &mm->pgtables_bytes, i: 0);
2744	}
2745
2746	static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm)
2747	{
2748	return atomic_long_read(v: &mm->pgtables_bytes);
2749	}
2750
2751	static inline void mm_inc_nr_ptes(struct mm_struct *mm)
2752	{
2753	atomic_long_add(PTRS_PER_PTE * sizeof(pte_t), v: &mm->pgtables_bytes);
2754	}
2755
2756	static inline void mm_dec_nr_ptes(struct mm_struct *mm)
2757	{
2758	atomic_long_sub(PTRS_PER_PTE * sizeof(pte_t), v: &mm->pgtables_bytes);
2759	}
2760	#else
2761
2762	static inline void mm_pgtables_bytes_init(struct mm_struct *mm) {}
2763	static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm)
2764	{
2765	return 0;
2766	}
2767
2768	static inline void mm_inc_nr_ptes(struct mm_struct *mm) {}
2769	static inline void mm_dec_nr_ptes(struct mm_struct *mm) {}
2770	#endif
2771
2772	int __pte_alloc(struct mm_struct *mm, pmd_t *pmd);
2773	int __pte_alloc_kernel(pmd_t *pmd);
2774
2775	#if defined(CONFIG_MMU)
2776
2777	static inline p4d_t *p4d_alloc(struct mm_struct *mm, pgd_t *pgd,
2778	unsigned long address)
2779	{
2780	return (unlikely(pgd_none(*pgd)) && __p4d_alloc(mm, pgd, address)) ?
2781	NULL : p4d_offset(pgd, address);
2782	}
2783
2784	static inline pud_t *pud_alloc(struct mm_struct *mm, p4d_t *p4d,
2785	unsigned long address)
2786	{
2787	return (unlikely(p4d_none(*p4d)) && __pud_alloc(mm, p4d, address)) ?
2788	NULL : pud_offset(p4d, address);
2789	}
2790
2791	static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2792	{
2793	return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
2794	NULL: pmd_offset(pud, address);
2795	}
2796	#endif /* CONFIG_MMU */
2797
2798	static inline struct ptdesc *virt_to_ptdesc(const void *x)
2799	{
2800	return page_ptdesc(virt_to_page(x));
2801	}
2802
2803	static inline void *ptdesc_to_virt(const struct ptdesc *pt)
2804	{
2805	return page_to_virt(ptdesc_page(pt));
2806	}
2807
2808	static inline void *ptdesc_address(const struct ptdesc *pt)
2809	{
2810	return folio_address(ptdesc_folio(pt));
2811	}
2812
2813	static inline bool pagetable_is_reserved(struct ptdesc *pt)
2814	{
2815	return folio_test_reserved(ptdesc_folio(pt));
2816	}
2817
2818	/**
2819	* pagetable_alloc - Allocate pagetables
2820	* @gfp: GFP flags
2821	* @order: desired pagetable order
2822	*
2823	* pagetable_alloc allocates memory for page tables as well as a page table
2824	* descriptor to describe that memory.
2825	*
2826	* Return: The ptdesc describing the allocated page tables.
2827	*/
2828	static inline struct ptdesc *pagetable_alloc(gfp_t gfp, unsigned int order)
2829	{
2830	struct page *page = alloc_pages(gfp: gfp | __GFP_COMP, order);
2831
2832	return page_ptdesc(page);
2833	}
2834
2835	/**
2836	* pagetable_free - Free pagetables
2837	* @pt: The page table descriptor
2838	*
2839	* pagetable_free frees the memory of all page tables described by a page
2840	* table descriptor and the memory for the descriptor itself.
2841	*/
2842	static inline void pagetable_free(struct ptdesc *pt)
2843	{
2844	struct page *page = ptdesc_page(pt);
2845
2846	__free_pages(page, order: compound_order(page));
2847	}
2848
2849	#if USE_SPLIT_PTE_PTLOCKS
2850	#if ALLOC_SPLIT_PTLOCKS
2851	void __init ptlock_cache_init(void);
2852	bool ptlock_alloc(struct ptdesc *ptdesc);
2853	void ptlock_free(struct ptdesc *ptdesc);
2854
2855	static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
2856	{
2857	return ptdesc->ptl;
2858	}
2859	#else /* ALLOC_SPLIT_PTLOCKS */
2860	static inline void ptlock_cache_init(void)
2861	{
2862	}
2863
2864	static inline bool ptlock_alloc(struct ptdesc *ptdesc)
2865	{
2866	return true;
2867	}
2868
2869	static inline void ptlock_free(struct ptdesc *ptdesc)
2870	{
2871	}
2872
2873	static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
2874	{
2875	return &ptdesc->ptl;
2876	}
2877	#endif /* ALLOC_SPLIT_PTLOCKS */
2878
2879	static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
2880	{
2881	return ptlock_ptr(page_ptdesc(pmd_page(*pmd)));
2882	}
2883
2884	static inline bool ptlock_init(struct ptdesc *ptdesc)
2885	{
2886	/*
2887	* prep_new_page() initialize page->private (and therefore page->ptl)
2888	* with 0. Make sure nobody took it in use in between.
2889	*
2890	* It can happen if arch try to use slab for page table allocation:
2891	* slab code uses page->slab_cache, which share storage with page->ptl.
2892	*/
2893	VM_BUG_ON_PAGE(*(unsigned long *)&ptdesc->ptl, ptdesc_page(ptdesc));
2894	if (!ptlock_alloc(ptdesc))
2895	return false;
2896	spin_lock_init(ptlock_ptr(ptdesc));
2897	return true;
2898	}
2899
2900	#else /* !USE_SPLIT_PTE_PTLOCKS */
2901	/*
2902	* We use mm->page_table_lock to guard all pagetable pages of the mm.
2903	*/
2904	static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
2905	{
2906	return &mm->page_table_lock;
2907	}
2908	static inline void ptlock_cache_init(void) {}
2909	static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
2910	static inline void ptlock_free(struct ptdesc *ptdesc) {}
2911	#endif /* USE_SPLIT_PTE_PTLOCKS */
2912
2913	static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc)
2914	{
2915	struct folio *folio = ptdesc_folio(ptdesc);
2916
2917	if (!ptlock_init(ptdesc))
2918	return false;
2919	__folio_set_pgtable(folio);
2920	lruvec_stat_add_folio(folio, idx: NR_PAGETABLE);
2921	return true;
2922	}
2923
2924	static inline void pagetable_pte_dtor(struct ptdesc *ptdesc)
2925	{
2926	struct folio *folio = ptdesc_folio(ptdesc);
2927
2928	ptlock_free(ptdesc);
2929	__folio_clear_pgtable(folio);
2930	lruvec_stat_sub_folio(folio, idx: NR_PAGETABLE);
2931	}
2932
2933	pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp);
2934	static inline pte_t *pte_offset_map(pmd_t *pmd, unsigned long addr)
2935	{
2936	return __pte_offset_map(pmd, addr, NULL);
2937	}
2938
2939	pte_t *__pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd,
2940	unsigned long addr, spinlock_t **ptlp);
2941	static inline pte_t *pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd,
2942	unsigned long addr, spinlock_t **ptlp)
2943	{
2944	pte_t *pte;
2945
2946	__cond_lock(*ptlp, pte = __pte_offset_map_lock(mm, pmd, addr, ptlp));
2947	return pte;
2948	}
2949
2950	pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd,
2951	unsigned long addr, spinlock_t **ptlp);
2952
2953	#define pte_unmap_unlock(pte, ptl) do { \
2954	spin_unlock(ptl); \
2955	pte_unmap(pte); \
2956	} while (0)
2957
2958	#define pte_alloc(mm, pmd) (unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, pmd))
2959
2960	#define pte_alloc_map(mm, pmd, address) \
2961	(pte_alloc(mm, pmd) ? NULL : pte_offset_map(pmd, address))
2962
2963	#define pte_alloc_map_lock(mm, pmd, address, ptlp) \
2964	(pte_alloc(mm, pmd) ? \
2965	NULL : pte_offset_map_lock(mm, pmd, address, ptlp))
2966
2967	#define pte_alloc_kernel(pmd, address) \
2968	((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd))? \
2969	NULL: pte_offset_kernel(pmd, address))
2970
2971	#if USE_SPLIT_PMD_PTLOCKS
2972
2973	static inline struct page *pmd_pgtable_page(pmd_t *pmd)
2974	{
2975	unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
2976	return virt_to_page((void *)((unsigned long) pmd & mask));
2977	}
2978
2979	static inline struct ptdesc *pmd_ptdesc(pmd_t *pmd)
2980	{
2981	return page_ptdesc(pmd_pgtable_page(pmd));
2982	}
2983
2984	static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
2985	{
2986	return ptlock_ptr(ptdesc: pmd_ptdesc(pmd));
2987	}
2988
2989	static inline bool pmd_ptlock_init(struct ptdesc *ptdesc)
2990	{
2991	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
2992	ptdesc->pmd_huge_pte = NULL;
2993	#endif
2994	return ptlock_init(ptdesc);
2995	}
2996
2997	static inline void pmd_ptlock_free(struct ptdesc *ptdesc)
2998	{
2999	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
3000	VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte, ptdesc_page(ptdesc));
3001	#endif
3002	ptlock_free(ptdesc);
3003	}
3004
3005	#define pmd_huge_pte(mm, pmd) (pmd_ptdesc(pmd)->pmd_huge_pte)
3006
3007	#else
3008
3009	static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
3010	{
3011	return &mm->page_table_lock;
3012	}
3013
3014	static inline bool pmd_ptlock_init(struct ptdesc *ptdesc) { return true; }
3015	static inline void pmd_ptlock_free(struct ptdesc *ptdesc) {}
3016
3017	#define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
3018
3019	#endif
3020
3021	static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
3022	{
3023	spinlock_t *ptl = pmd_lockptr(mm, pmd);
3024	spin_lock(lock: ptl);
3025	return ptl;
3026	}
3027
3028	static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc)
3029	{
3030	struct folio *folio = ptdesc_folio(ptdesc);
3031
3032	if (!pmd_ptlock_init(ptdesc))
3033	return false;
3034	__folio_set_pgtable(folio);
3035	lruvec_stat_add_folio(folio, idx: NR_PAGETABLE);
3036	return true;
3037	}
3038
3039	static inline void pagetable_pmd_dtor(struct ptdesc *ptdesc)
3040	{
3041	struct folio *folio = ptdesc_folio(ptdesc);
3042
3043	pmd_ptlock_free(ptdesc);
3044	__folio_clear_pgtable(folio);
3045	lruvec_stat_sub_folio(folio, idx: NR_PAGETABLE);
3046	}
3047
3048	/*
3049	* No scalability reason to split PUD locks yet, but follow the same pattern
3050	* as the PMD locks to make it easier if we decide to. The VM should not be
3051	* considered ready to switch to split PUD locks yet; there may be places
3052	* which need to be converted from page_table_lock.
3053	*/
3054	static inline spinlock_t *pud_lockptr(struct mm_struct *mm, pud_t *pud)
3055	{
3056	return &mm->page_table_lock;
3057	}
3058
3059	static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud)
3060	{
3061	spinlock_t *ptl = pud_lockptr(mm, pud);
3062
3063	spin_lock(lock: ptl);
3064	return ptl;
3065	}
3066
3067	static inline void pagetable_pud_ctor(struct ptdesc *ptdesc)
3068	{
3069	struct folio *folio = ptdesc_folio(ptdesc);
3070
3071	__folio_set_pgtable(folio);
3072	lruvec_stat_add_folio(folio, idx: NR_PAGETABLE);
3073	}
3074
3075	static inline void pagetable_pud_dtor(struct ptdesc *ptdesc)
3076	{
3077	struct folio *folio = ptdesc_folio(ptdesc);
3078
3079	__folio_clear_pgtable(folio);
3080	lruvec_stat_sub_folio(folio, idx: NR_PAGETABLE);
3081	}
3082
3083	extern void __init pagecache_init(void);
3084	extern void free_initmem(void);
3085
3086	/*
3087	* Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
3088	* into the buddy system. The freed pages will be poisoned with pattern
3089	* "poison" if it's within range [0, UCHAR_MAX].
3090	* Return pages freed into the buddy system.
3091	*/
3092	extern unsigned long free_reserved_area(void *start, void *end,
3093	int poison, const char *s);
3094
3095	extern void adjust_managed_page_count(struct page *page, long count);
3096
3097	extern void reserve_bootmem_region(phys_addr_t start,
3098	phys_addr_t end, int nid);
3099
3100	/* Free the reserved page into the buddy system, so it gets managed. */
3101	static inline void free_reserved_page(struct page *page)
3102	{
3103	ClearPageReserved(page);
3104	init_page_count(page);
3105	__free_page(page);
3106	adjust_managed_page_count(page, count: 1);
3107	}
3108	#define free_highmem_page(page) free_reserved_page(page)
3109
3110	static inline void mark_page_reserved(struct page *page)
3111	{
3112	SetPageReserved(page);
3113	adjust_managed_page_count(page, count: -1);
3114	}
3115
3116	static inline void free_reserved_ptdesc(struct ptdesc *pt)
3117	{
3118	free_reserved_page(ptdesc_page(pt));
3119	}
3120
3121	/*
3122	* Default method to free all the __init memory into the buddy system.
3123	* The freed pages will be poisoned with pattern "poison" if it's within
3124	* range [0, UCHAR_MAX].
3125	* Return pages freed into the buddy system.
3126	*/
3127	static inline unsigned long free_initmem_default(int poison)
3128	{
3129	extern char __init_begin[], __init_end[];
3130
3131	return free_reserved_area(start: &__init_begin, end: &__init_end,
3132	poison, s: "unused kernel image (initmem)");
3133	}
3134
3135	static inline unsigned long get_num_physpages(void)
3136	{
3137	int nid;
3138	unsigned long phys_pages = 0;
3139
3140	for_each_online_node(nid)
3141	phys_pages += node_present_pages(nid);
3142
3143	return phys_pages;
3144	}
3145
3146	/*
3147	* Using memblock node mappings, an architecture may initialise its
3148	* zones, allocate the backing mem_map and account for memory holes in an
3149	* architecture independent manner.
3150	*
3151	* An architecture is expected to register range of page frames backed by
3152	* physical memory with memblock_add[_node]() before calling
3153	* free_area_init() passing in the PFN each zone ends at. At a basic
3154	* usage, an architecture is expected to do something like
3155	*
3156	* unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
3157	* max_highmem_pfn};
3158	* for_each_valid_physical_page_range()
3159	* memblock_add_node(base, size, nid, MEMBLOCK_NONE)
3160	* free_area_init(max_zone_pfns);
3161	*/
3162	void free_area_init(unsigned long *max_zone_pfn);
3163	unsigned long node_map_pfn_alignment(void);
3164	unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
3165	unsigned long end_pfn);
3166	extern unsigned long absent_pages_in_range(unsigned long start_pfn,
3167	unsigned long end_pfn);
3168	extern void get_pfn_range_for_nid(unsigned int nid,
3169	unsigned long *start_pfn, unsigned long *end_pfn);
3170
3171	#ifndef CONFIG_NUMA
3172	static inline int early_pfn_to_nid(unsigned long pfn)
3173	{
3174	return 0;
3175	}
3176	#else
3177	/* please see mm/page_alloc.c */
3178	extern int __meminit early_pfn_to_nid(unsigned long pfn);
3179	#endif
3180
3181	extern void set_dma_reserve(unsigned long new_dma_reserve);
3182	extern void mem_init(void);
3183	extern void __init mmap_init(void);
3184
3185	extern void __show_mem(unsigned int flags, nodemask_t *nodemask, int max_zone_idx);
3186	static inline void show_mem(void)
3187	{
3188	__show_mem(flags: 0, NULL, max_zone_idx: MAX_NR_ZONES - 1);
3189	}
3190	extern long si_mem_available(void);
3191	extern void si_meminfo(struct sysinfo * val);
3192	extern void si_meminfo_node(struct sysinfo *val, int nid);
3193	#ifdef __HAVE_ARCH_RESERVED_KERNEL_PAGES
3194	extern unsigned long arch_reserved_kernel_pages(void);
3195	#endif
3196
3197	extern __printf(3, 4)
3198	void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...);
3199
3200	extern void setup_per_cpu_pageset(void);
3201
3202	/* nommu.c */
3203	extern atomic_long_t mmap_pages_allocated;
3204	extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
3205
3206	/* interval_tree.c */
3207	void vma_interval_tree_insert(struct vm_area_struct *node,
3208	struct rb_root_cached *root);
3209	void vma_interval_tree_insert_after(struct vm_area_struct *node,
3210	struct vm_area_struct *prev,
3211	struct rb_root_cached *root);
3212	void vma_interval_tree_remove(struct vm_area_struct *node,
3213	struct rb_root_cached *root);
3214	struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
3215	unsigned long start, unsigned long last);
3216	struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
3217	unsigned long start, unsigned long last);
3218
3219	#define vma_interval_tree_foreach(vma, root, start, last) \
3220	for (vma = vma_interval_tree_iter_first(root, start, last); \
3221	vma; vma = vma_interval_tree_iter_next(vma, start, last))
3222
3223	void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
3224	struct rb_root_cached *root);
3225	void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
3226	struct rb_root_cached *root);
3227	struct anon_vma_chain *
3228	anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
3229	unsigned long start, unsigned long last);
3230	struct anon_vma_chain *anon_vma_interval_tree_iter_next(
3231	struct anon_vma_chain *node, unsigned long start, unsigned long last);
3232	#ifdef CONFIG_DEBUG_VM_RB
3233	void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
3234	#endif
3235
3236	#define anon_vma_interval_tree_foreach(avc, root, start, last) \
3237	for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
3238	avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
3239
3240	/* mmap.c */
3241	extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
3242	extern int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
3243	unsigned long start, unsigned long end, pgoff_t pgoff,
3244	struct vm_area_struct *next);
3245	extern int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
3246	unsigned long start, unsigned long end, pgoff_t pgoff);
3247	extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
3248	extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
3249	extern void unlink_file_vma(struct vm_area_struct *);
3250	extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
3251	unsigned long addr, unsigned long len, pgoff_t pgoff,
3252	bool *need_rmap_locks);
3253	extern void exit_mmap(struct mm_struct *);
3254	struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
3255	struct vm_area_struct *prev,
3256	struct vm_area_struct *vma,
3257	unsigned long start, unsigned long end,
3258	unsigned long vm_flags,
3259	struct mempolicy *policy,
3260	struct vm_userfaultfd_ctx uffd_ctx,
3261	struct anon_vma_name *anon_name);
3262
3263	/* We are about to modify the VMA's flags. */
3264	static inline struct vm_area_struct
3265	*vma_modify_flags(struct vma_iterator *vmi,
3266	struct vm_area_struct *prev,
3267	struct vm_area_struct *vma,
3268	unsigned long start, unsigned long end,
3269	unsigned long new_flags)
3270	{
3271	return vma_modify(vmi, prev, vma, start, end, vm_flags: new_flags,
3272	vma_policy(vma), uffd_ctx: vma->vm_userfaultfd_ctx,
3273	anon_name: anon_vma_name(vma));
3274	}
3275
3276	/* We are about to modify the VMA's flags and/or anon_name. */
3277	static inline struct vm_area_struct
3278	*vma_modify_flags_name(struct vma_iterator *vmi,
3279	struct vm_area_struct *prev,
3280	struct vm_area_struct *vma,
3281	unsigned long start,
3282	unsigned long end,
3283	unsigned long new_flags,
3284	struct anon_vma_name *new_name)
3285	{
3286	return vma_modify(vmi, prev, vma, start, end, vm_flags: new_flags,
3287	vma_policy(vma), uffd_ctx: vma->vm_userfaultfd_ctx, anon_name: new_name);
3288	}
3289
3290	/* We are about to modify the VMA's memory policy. */
3291	static inline struct vm_area_struct
3292	*vma_modify_policy(struct vma_iterator *vmi,
3293	struct vm_area_struct *prev,
3294	struct vm_area_struct *vma,
3295	unsigned long start, unsigned long end,
3296	struct mempolicy *new_pol)
3297	{
3298	return vma_modify(vmi, prev, vma, start, end, vm_flags: vma->vm_flags,
3299	policy: new_pol, uffd_ctx: vma->vm_userfaultfd_ctx, anon_name: anon_vma_name(vma));
3300	}
3301
3302	/* We are about to modify the VMA's flags and/or uffd context. */
3303	static inline struct vm_area_struct
3304	*vma_modify_flags_uffd(struct vma_iterator *vmi,
3305	struct vm_area_struct *prev,
3306	struct vm_area_struct *vma,
3307	unsigned long start, unsigned long end,
3308	unsigned long new_flags,
3309	struct vm_userfaultfd_ctx new_ctx)
3310	{
3311	return vma_modify(vmi, prev, vma, start, end, vm_flags: new_flags,
3312	vma_policy(vma), uffd_ctx: new_ctx, anon_name: anon_vma_name(vma));
3313	}
3314
3315	static inline int check_data_rlimit(unsigned long rlim,
3316	unsigned long new,
3317	unsigned long start,
3318	unsigned long end_data,
3319	unsigned long start_data)
3320	{
3321	if (rlim < RLIM_INFINITY) {
3322	if (((new - start) + (end_data - start_data)) > rlim)
3323	return -ENOSPC;
3324	}
3325
3326	return 0;
3327	}
3328
3329	extern int mm_take_all_locks(struct mm_struct *mm);
3330	extern void mm_drop_all_locks(struct mm_struct *mm);
3331
3332	extern int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
3333	extern int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
3334	extern struct file *get_mm_exe_file(struct mm_struct *mm);
3335	extern struct file *get_task_exe_file(struct task_struct *task);
3336
3337	extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages);
3338	extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages);
3339
3340	extern bool vma_is_special_mapping(const struct vm_area_struct *vma,
3341	const struct vm_special_mapping *sm);
3342	extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
3343	unsigned long addr, unsigned long len,
3344	unsigned long flags,
3345	const struct vm_special_mapping *spec);
3346	/* This is an obsolete alternative to _install_special_mapping. */
3347	extern int install_special_mapping(struct mm_struct *mm,
3348	unsigned long addr, unsigned long len,
3349	unsigned long flags, struct page **pages);
3350
3351	unsigned long randomize_stack_top(unsigned long stack_top);
3352	unsigned long randomize_page(unsigned long start, unsigned long range);
3353
3354	extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
3355
3356	extern unsigned long mmap_region(struct file *file, unsigned long addr,
3357	unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
3358	struct list_head *uf);
3359	extern unsigned long do_mmap(struct file *file, unsigned long addr,
3360	unsigned long len, unsigned long prot, unsigned long flags,
3361	vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
3362	struct list_head *uf);
3363	extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
3364	unsigned long start, size_t len, struct list_head *uf,
3365	bool unlock);
3366	extern int do_munmap(struct mm_struct *, unsigned long, size_t,
3367	struct list_head *uf);
3368	extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior);
3369
3370	#ifdef CONFIG_MMU
3371	extern int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
3372	unsigned long start, unsigned long end,
3373	struct list_head *uf, bool unlock);
3374	extern int __mm_populate(unsigned long addr, unsigned long len,
3375	int ignore_errors);
3376	static inline void mm_populate(unsigned long addr, unsigned long len)
3377	{
3378	/* Ignore errors */
3379	(void) __mm_populate(addr, len, ignore_errors: 1);
3380	}
3381	#else
3382	static inline void mm_populate(unsigned long addr, unsigned long len) {}
3383	#endif
3384
3385	/* This takes the mm semaphore itself */
3386	extern int __must_check vm_brk_flags(unsigned long, unsigned long, unsigned long);
3387	extern int vm_munmap(unsigned long, size_t);
3388	extern unsigned long __must_check vm_mmap(struct file *, unsigned long,
3389	unsigned long, unsigned long,
3390	unsigned long, unsigned long);
3391
3392	struct vm_unmapped_area_info {
3393	#define VM_UNMAPPED_AREA_TOPDOWN 1
3394	unsigned long flags;
3395	unsigned long length;
3396	unsigned long low_limit;
3397	unsigned long high_limit;
3398	unsigned long align_mask;
3399	unsigned long align_offset;
3400	};
3401
3402	extern unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info);
3403
3404	/* truncate.c */
3405	extern void truncate_inode_pages(struct address_space *, loff_t);
3406	extern void truncate_inode_pages_range(struct address_space *,
3407	loff_t lstart, loff_t lend);
3408	extern void truncate_inode_pages_final(struct address_space *);
3409
3410	/* generic vm_area_ops exported for stackable file systems */
3411	extern vm_fault_t filemap_fault(struct vm_fault *vmf);
3412	extern vm_fault_t filemap_map_pages(struct vm_fault *vmf,
3413	pgoff_t start_pgoff, pgoff_t end_pgoff);
3414	extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf);
3415
3416	extern unsigned long stack_guard_gap;
3417	/* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
3418	int expand_stack_locked(struct vm_area_struct *vma, unsigned long address);
3419	struct vm_area_struct *expand_stack(struct mm_struct * mm, unsigned long addr);
3420
3421	/* CONFIG_STACK_GROWSUP still needs to grow downwards at some places */
3422	int expand_downwards(struct vm_area_struct *vma, unsigned long address);
3423
3424	/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
3425	extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
3426	extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
3427	struct vm_area_struct **pprev);
3428
3429	/*
3430	* Look up the first VMA which intersects the interval [start_addr, end_addr)
3431	* NULL if none. Assume start_addr < end_addr.
3432	*/
3433	struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
3434	unsigned long start_addr, unsigned long end_addr);
3435
3436	/**
3437	* vma_lookup() - Find a VMA at a specific address
3438	* @mm: The process address space.
3439	* @addr: The user address.
3440	*
3441	* Return: The vm_area_struct at the given address, %NULL otherwise.
3442	*/
3443	static inline
3444	struct vm_area_struct *vma_lookup(struct mm_struct *mm, unsigned long addr)
3445	{
3446	return mtree_load(mt: &mm->mm_mt, index: addr);
3447	}
3448
3449	static inline unsigned long stack_guard_start_gap(struct vm_area_struct *vma)
3450	{
3451	if (vma->vm_flags & VM_GROWSDOWN)
3452	return stack_guard_gap;
3453
3454	/* See reasoning around the VM_SHADOW_STACK definition */
3455	if (vma->vm_flags & VM_SHADOW_STACK)
3456	return PAGE_SIZE;
3457
3458	return 0;
3459	}
3460
3461	static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
3462	{
3463	unsigned long gap = stack_guard_start_gap(vma);
3464	unsigned long vm_start = vma->vm_start;
3465
3466	vm_start -= gap;
3467	if (vm_start > vma->vm_start)
3468	vm_start = 0;
3469	return vm_start;
3470	}
3471
3472	static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
3473	{
3474	unsigned long vm_end = vma->vm_end;
3475
3476	if (vma->vm_flags & VM_GROWSUP) {
3477	vm_end += stack_guard_gap;
3478	if (vm_end < vma->vm_end)
3479	vm_end = -PAGE_SIZE;
3480	}
3481	return vm_end;
3482	}
3483
3484	static inline unsigned long vma_pages(struct vm_area_struct *vma)
3485	{
3486	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
3487	}
3488
3489	/* Look up the first VMA which exactly match the interval vm_start ... vm_end */
3490	static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
3491	unsigned long vm_start, unsigned long vm_end)
3492	{
3493	struct vm_area_struct *vma = vma_lookup(mm, addr: vm_start);
3494
3495	if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
3496	vma = NULL;
3497
3498	return vma;
3499	}
3500
3501	static inline bool range_in_vma(struct vm_area_struct *vma,
3502	unsigned long start, unsigned long end)
3503	{
3504	return (vma && vma->vm_start <= start && end <= vma->vm_end);
3505	}
3506
3507	#ifdef CONFIG_MMU
3508	pgprot_t vm_get_page_prot(unsigned long vm_flags);
3509	void vma_set_page_prot(struct vm_area_struct *vma);
3510	#else
3511	static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
3512	{
3513	return __pgprot(0);
3514	}
3515	static inline void vma_set_page_prot(struct vm_area_struct *vma)
3516	{
3517	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
3518	}
3519	#endif
3520
3521	void vma_set_file(struct vm_area_struct *vma, struct file *file);
3522
3523	#ifdef CONFIG_NUMA_BALANCING
3524	unsigned long change_prot_numa(struct vm_area_struct *vma,
3525	unsigned long start, unsigned long end);
3526	#endif
3527
3528	struct vm_area_struct *find_extend_vma_locked(struct mm_struct *,
3529	unsigned long addr);
3530	int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
3531	unsigned long pfn, unsigned long size, pgprot_t);
3532	int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr,
3533	unsigned long pfn, unsigned long size, pgprot_t prot);
3534	int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
3535	int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr,
3536	struct page **pages, unsigned long *num);
3537	int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
3538	unsigned long num);
3539	int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
3540	unsigned long num);
3541	vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
3542	unsigned long pfn);
3543	vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
3544	unsigned long pfn, pgprot_t pgprot);
3545	vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
3546	pfn_t pfn);
3547	vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma,
3548	unsigned long addr, pfn_t pfn);
3549	int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
3550
3551	static inline vm_fault_t vmf_insert_page(struct vm_area_struct *vma,
3552	unsigned long addr, struct page *page)
3553	{
3554	int err = vm_insert_page(vma, addr, page);
3555
3556	if (err == -ENOMEM)
3557	return VM_FAULT_OOM;
3558	if (err < 0 && err != -EBUSY)
3559	return VM_FAULT_SIGBUS;
3560
3561	return VM_FAULT_NOPAGE;
3562	}
3563
3564	#ifndef io_remap_pfn_range
3565	static inline int io_remap_pfn_range(struct vm_area_struct *vma,
3566	unsigned long addr, unsigned long pfn,
3567	unsigned long size, pgprot_t prot)
3568	{
3569	return remap_pfn_range(vma, addr, pfn, size, pgprot_decrypted(prot));
3570	}
3571	#endif
3572
3573	static inline vm_fault_t vmf_error(int err)
3574	{
3575	if (err == -ENOMEM)
3576	return VM_FAULT_OOM;
3577	else if (err == -EHWPOISON)
3578	return VM_FAULT_HWPOISON;
3579	return VM_FAULT_SIGBUS;
3580	}
3581
3582	/*
3583	* Convert errno to return value for ->page_mkwrite() calls.
3584	*
3585	* This should eventually be merged with vmf_error() above, but will need a
3586	* careful audit of all vmf_error() callers.
3587	*/
3588	static inline vm_fault_t vmf_fs_error(int err)
3589	{
3590	if (err == 0)
3591	return VM_FAULT_LOCKED;
3592	if (err == -EFAULT || err == -EAGAIN)
3593	return VM_FAULT_NOPAGE;
3594	if (err == -ENOMEM)
3595	return VM_FAULT_OOM;
3596	/* -ENOSPC, -EDQUOT, -EIO ... */
3597	return VM_FAULT_SIGBUS;
3598	}
3599
3600	struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
3601	unsigned int foll_flags);
3602
3603	static inline int vm_fault_to_errno(vm_fault_t vm_fault, int foll_flags)
3604	{
3605	if (vm_fault & VM_FAULT_OOM)
3606	return -ENOMEM;
3607	if (vm_fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
3608	return (foll_flags & FOLL_HWPOISON) ? -EHWPOISON : -EFAULT;
3609	if (vm_fault & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV))
3610	return -EFAULT;
3611	return 0;
3612	}
3613
3614	/*
3615	* Indicates whether GUP can follow a PROT_NONE mapped page, or whether
3616	* a (NUMA hinting) fault is required.
3617	*/
3618	static inline bool gup_can_follow_protnone(struct vm_area_struct *vma,
3619	unsigned int flags)
3620	{
3621	/*
3622	* If callers don't want to honor NUMA hinting faults, no need to
3623	* determine if we would actually have to trigger a NUMA hinting fault.
3624	*/
3625	if (!(flags & FOLL_HONOR_NUMA_FAULT))
3626	return true;
3627
3628	/*
3629	* NUMA hinting faults don't apply in inaccessible (PROT_NONE) VMAs.
3630	*
3631	* Requiring a fault here even for inaccessible VMAs would mean that
3632	* FOLL_FORCE cannot make any progress, because handle_mm_fault()
3633	* refuses to process NUMA hinting faults in inaccessible VMAs.
3634	*/
3635	return !vma_is_accessible(vma);
3636	}
3637
3638	typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data);
3639	extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
3640	unsigned long size, pte_fn_t fn, void *data);
3641	extern int apply_to_existing_page_range(struct mm_struct *mm,
3642	unsigned long address, unsigned long size,
3643	pte_fn_t fn, void *data);
3644
3645	#ifdef CONFIG_PAGE_POISONING
3646	extern void __kernel_poison_pages(struct page *page, int numpages);
3647	extern void __kernel_unpoison_pages(struct page *page, int numpages);
3648	extern bool _page_poisoning_enabled_early;
3649	DECLARE_STATIC_KEY_FALSE(_page_poisoning_enabled);
3650	static inline bool page_poisoning_enabled(void)
3651	{
3652	return _page_poisoning_enabled_early;
3653	}
3654	/*
3655	* For use in fast paths after init_mem_debugging() has run, or when a
3656	* false negative result is not harmful when called too early.
3657	*/
3658	static inline bool page_poisoning_enabled_static(void)
3659	{
3660	return static_branch_unlikely(&_page_poisoning_enabled);
3661	}
3662	static inline void kernel_poison_pages(struct page *page, int numpages)
3663	{
3664	if (page_poisoning_enabled_static())
3665	__kernel_poison_pages(page, numpages);
3666	}
3667	static inline void kernel_unpoison_pages(struct page *page, int numpages)
3668	{
3669	if (page_poisoning_enabled_static())
3670	__kernel_unpoison_pages(page, numpages);
3671	}
3672	#else
3673	static inline bool page_poisoning_enabled(void) { return false; }
3674	static inline bool page_poisoning_enabled_static(void) { return false; }
3675	static inline void __kernel_poison_pages(struct page *page, int nunmpages) { }
3676	static inline void kernel_poison_pages(struct page *page, int numpages) { }
3677	static inline void kernel_unpoison_pages(struct page *page, int numpages) { }
3678	#endif
3679
3680	DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc);
3681	static inline bool want_init_on_alloc(gfp_t flags)
3682	{
3683	if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
3684	&init_on_alloc))
3685	return true;
3686	return flags & __GFP_ZERO;
3687	}
3688
3689	DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free);
3690	static inline bool want_init_on_free(void)
3691	{
3692	return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
3693	&init_on_free);
3694	}
3695
3696	extern bool _debug_pagealloc_enabled_early;
3697	DECLARE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
3698
3699	static inline bool debug_pagealloc_enabled(void)
3700	{
3701	return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) &&
3702	_debug_pagealloc_enabled_early;
3703	}
3704
3705	/*
3706	* For use in fast paths after mem_debugging_and_hardening_init() has run,
3707	* or when a false negative result is not harmful when called too early.
3708	*/
3709	static inline bool debug_pagealloc_enabled_static(void)
3710	{
3711	if (!IS_ENABLED(CONFIG_DEBUG_PAGEALLOC))
3712	return false;
3713
3714	return static_branch_unlikely(&_debug_pagealloc_enabled);
3715	}
3716
3717	/*
3718	* To support DEBUG_PAGEALLOC architecture must ensure that
3719	* __kernel_map_pages() never fails
3720	*/
3721	extern void __kernel_map_pages(struct page *page, int numpages, int enable);
3722	#ifdef CONFIG_DEBUG_PAGEALLOC
3723	static inline void debug_pagealloc_map_pages(struct page *page, int numpages)
3724	{
3725	if (debug_pagealloc_enabled_static())
3726	__kernel_map_pages(page, numpages, enable: 1);
3727	}
3728
3729	static inline void debug_pagealloc_unmap_pages(struct page *page, int numpages)
3730	{
3731	if (debug_pagealloc_enabled_static())
3732	__kernel_map_pages(page, numpages, enable: 0);
3733	}
3734
3735	extern unsigned int _debug_guardpage_minorder;
3736	DECLARE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
3737
3738	static inline unsigned int debug_guardpage_minorder(void)
3739	{
3740	return _debug_guardpage_minorder;
3741	}
3742
3743	static inline bool debug_guardpage_enabled(void)
3744	{
3745	return static_branch_unlikely(&_debug_guardpage_enabled);
3746	}
3747
3748	static inline bool page_is_guard(struct page *page)
3749	{
3750	if (!debug_guardpage_enabled())
3751	return false;
3752
3753	return PageGuard(page);
3754	}
3755
3756	bool __set_page_guard(struct zone *zone, struct page *page, unsigned int order,
3757	int migratetype);
3758	static inline bool set_page_guard(struct zone *zone, struct page *page,
3759	unsigned int order, int migratetype)
3760	{
3761	if (!debug_guardpage_enabled())
3762	return false;
3763	return __set_page_guard(zone, page, order, migratetype);
3764	}
3765
3766	void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order,
3767	int migratetype);
3768	static inline void clear_page_guard(struct zone *zone, struct page *page,
3769	unsigned int order, int migratetype)
3770	{
3771	if (!debug_guardpage_enabled())
3772	return;
3773	__clear_page_guard(zone, page, order, migratetype);
3774	}
3775
3776	#else /* CONFIG_DEBUG_PAGEALLOC */
3777	static inline void debug_pagealloc_map_pages(struct page *page, int numpages) {}
3778	static inline void debug_pagealloc_unmap_pages(struct page *page, int numpages) {}
3779	static inline unsigned int debug_guardpage_minorder(void) { return 0; }
3780	static inline bool debug_guardpage_enabled(void) { return false; }
3781	static inline bool page_is_guard(struct page *page) { return false; }
3782	static inline bool set_page_guard(struct zone *zone, struct page *page,
3783	unsigned int order, int migratetype) { return false; }
3784	static inline void clear_page_guard(struct zone *zone, struct page *page,
3785	unsigned int order, int migratetype) {}
3786	#endif /* CONFIG_DEBUG_PAGEALLOC */
3787
3788	#ifdef __HAVE_ARCH_GATE_AREA
3789	extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
3790	extern int in_gate_area_no_mm(unsigned long addr);
3791	extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
3792	#else
3793	static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
3794	{
3795	return NULL;
3796	}
3797	static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
3798	static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
3799	{
3800	return 0;
3801	}
3802	#endif /* __HAVE_ARCH_GATE_AREA */
3803
3804	extern bool process_shares_mm(struct task_struct *p, struct mm_struct *mm);
3805
3806	#ifdef CONFIG_SYSCTL
3807	extern int sysctl_drop_caches;
3808	int drop_caches_sysctl_handler(struct ctl_table *, int, void *, size_t *,
3809	loff_t *);
3810	#endif
3811
3812	void drop_slab(void);
3813
3814	#ifndef CONFIG_MMU
3815	#define randomize_va_space 0
3816	#else
3817	extern int randomize_va_space;
3818	#endif
3819
3820	const char * arch_vma_name(struct vm_area_struct *vma);
3821	#ifdef CONFIG_MMU
3822	void print_vma_addr(char *prefix, unsigned long rip);
3823	#else
3824	static inline void print_vma_addr(char *prefix, unsigned long rip)
3825	{
3826	}
3827	#endif
3828
3829	void *sparse_buffer_alloc(unsigned long size);
3830	struct page * __populate_section_memmap(unsigned long pfn,
3831	unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
3832	struct dev_pagemap *pgmap);
3833	void pmd_init(void *addr);
3834	void pud_init(void *addr);
3835	pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
3836	p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
3837	pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
3838	pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
3839	pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
3840	struct vmem_altmap *altmap, struct page *reuse);
3841	void *vmemmap_alloc_block(unsigned long size, int node);
3842	struct vmem_altmap;
3843	void *vmemmap_alloc_block_buf(unsigned long size, int node,
3844	struct vmem_altmap *altmap);
3845	void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
3846	void vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
3847	unsigned long addr, unsigned long next);
3848	int vmemmap_check_pmd(pmd_t *pmd, int node,
3849	unsigned long addr, unsigned long next);
3850	int vmemmap_populate_basepages(unsigned long start, unsigned long end,
3851	int node, struct vmem_altmap *altmap);
3852	int vmemmap_populate_hugepages(unsigned long start, unsigned long end,
3853	int node, struct vmem_altmap *altmap);
3854	int vmemmap_populate(unsigned long start, unsigned long end, int node,
3855	struct vmem_altmap *altmap);
3856	void vmemmap_populate_print_last(void);
3857	#ifdef CONFIG_MEMORY_HOTPLUG
3858	void vmemmap_free(unsigned long start, unsigned long end,
3859	struct vmem_altmap *altmap);
3860	#endif
3861
3862	#define VMEMMAP_RESERVE_NR 2
3863	#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
3864	static inline bool __vmemmap_can_optimize(struct vmem_altmap *altmap,
3865	struct dev_pagemap *pgmap)
3866	{
3867	unsigned long nr_pages;
3868	unsigned long nr_vmemmap_pages;
3869
3870	if (!pgmap || !is_power_of_2(n: sizeof(struct page)))
3871	return false;
3872
3873	nr_pages = pgmap_vmemmap_nr(pgmap);
3874	nr_vmemmap_pages = ((nr_pages * sizeof(struct page)) >> PAGE_SHIFT);
3875	/*
3876	* For vmemmap optimization with DAX we need minimum 2 vmemmap
3877	* pages. See layout diagram in Documentation/mm/vmemmap_dedup.rst
3878	*/
3879	return !altmap && (nr_vmemmap_pages > VMEMMAP_RESERVE_NR);
3880	}
3881	/*
3882	* If we don't have an architecture override, use the generic rule
3883	*/
3884	#ifndef vmemmap_can_optimize
3885	#define vmemmap_can_optimize __vmemmap_can_optimize
3886	#endif
3887
3888	#else
3889	static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap,
3890	struct dev_pagemap *pgmap)
3891	{
3892	return false;
3893	}
3894	#endif
3895
3896	void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
3897	unsigned long nr_pages);
3898
3899	enum mf_flags {
3900	MF_COUNT_INCREASED = 1 << 0,
3901	MF_ACTION_REQUIRED = 1 << 1,
3902	MF_MUST_KILL = 1 << 2,
3903	MF_SOFT_OFFLINE = 1 << 3,
3904	MF_UNPOISON = 1 << 4,
3905	MF_SW_SIMULATED = 1 << 5,
3906	MF_NO_RETRY = 1 << 6,
3907	};
3908	int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index,
3909	unsigned long count, int mf_flags);
3910	extern int memory_failure(unsigned long pfn, int flags);
3911	extern void memory_failure_queue_kick(int cpu);
3912	extern int unpoison_memory(unsigned long pfn);
3913	extern void shake_page(struct page *p);
3914	extern atomic_long_t num_poisoned_pages __read_mostly;
3915	extern int soft_offline_page(unsigned long pfn, int flags);
3916	#ifdef CONFIG_MEMORY_FAILURE
3917	/*
3918	* Sysfs entries for memory failure handling statistics.
3919	*/
3920	extern const struct attribute_group memory_failure_attr_group;
3921	extern void memory_failure_queue(unsigned long pfn, int flags);
3922	extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
3923	bool *migratable_cleared);
3924	void num_poisoned_pages_inc(unsigned long pfn);
3925	void num_poisoned_pages_sub(unsigned long pfn, long i);
3926	struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
3927	#else
3928	static inline void memory_failure_queue(unsigned long pfn, int flags)
3929	{
3930	}
3931
3932	static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
3933	bool *migratable_cleared)
3934	{
3935	return 0;
3936	}
3937
3938	static inline void num_poisoned_pages_inc(unsigned long pfn)
3939	{
3940	}
3941
3942	static inline void num_poisoned_pages_sub(unsigned long pfn, long i)
3943	{
3944	}
3945	#endif
3946
3947	#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_KSM)
3948	void add_to_kill_ksm(struct task_struct *tsk, struct page *p,
3949	struct vm_area_struct *vma, struct list_head *to_kill,
3950	unsigned long ksm_addr);
3951	#endif
3952
3953	#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
3954	extern void memblk_nr_poison_inc(unsigned long pfn);
3955	extern void memblk_nr_poison_sub(unsigned long pfn, long i);
3956	#else
3957	static inline void memblk_nr_poison_inc(unsigned long pfn)
3958	{
3959	}
3960
3961	static inline void memblk_nr_poison_sub(unsigned long pfn, long i)
3962	{
3963	}
3964	#endif
3965
3966	#ifndef arch_memory_failure
3967	static inline int arch_memory_failure(unsigned long pfn, int flags)
3968	{
3969	return -ENXIO;
3970	}
3971	#endif
3972
3973	#ifndef arch_is_platform_page
3974	static inline bool arch_is_platform_page(u64 paddr)
3975	{
3976	return false;
3977	}
3978	#endif
3979
3980	/*
3981	* Error handlers for various types of pages.
3982	*/
3983	enum mf_result {
3984	MF_IGNORED, /* Error: cannot be handled */
3985	MF_FAILED, /* Error: handling failed */
3986	MF_DELAYED, /* Will be handled later */
3987	MF_RECOVERED, /* Successfully recovered */
3988	};
3989
3990	enum mf_action_page_type {
3991	MF_MSG_KERNEL,
3992	MF_MSG_KERNEL_HIGH_ORDER,
3993	MF_MSG_SLAB,
3994	MF_MSG_DIFFERENT_COMPOUND,
3995	MF_MSG_HUGE,
3996	MF_MSG_FREE_HUGE,
3997	MF_MSG_UNMAP_FAILED,
3998	MF_MSG_DIRTY_SWAPCACHE,
3999	MF_MSG_CLEAN_SWAPCACHE,
4000	MF_MSG_DIRTY_MLOCKED_LRU,
4001	MF_MSG_CLEAN_MLOCKED_LRU,
4002	MF_MSG_DIRTY_UNEVICTABLE_LRU,
4003	MF_MSG_CLEAN_UNEVICTABLE_LRU,
4004	MF_MSG_DIRTY_LRU,
4005	MF_MSG_CLEAN_LRU,
4006	MF_MSG_TRUNCATED_LRU,
4007	MF_MSG_BUDDY,
4008	MF_MSG_DAX,
4009	MF_MSG_UNSPLIT_THP,
4010	MF_MSG_UNKNOWN,
4011	};
4012
4013	#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4014	extern void clear_huge_page(struct page *page,
4015	unsigned long addr_hint,
4016	unsigned int pages_per_huge_page);
4017	int copy_user_large_folio(struct folio *dst, struct folio *src,
4018	unsigned long addr_hint,
4019	struct vm_area_struct *vma);
4020	long copy_folio_from_user(struct folio *dst_folio,
4021	const void __user *usr_src,
4022	bool allow_pagefault);
4023
4024	/**
4025	* vma_is_special_huge - Are transhuge page-table entries considered special?
4026	* @vma: Pointer to the struct vm_area_struct to consider
4027	*
4028	* Whether transhuge page-table entries are considered "special" following
4029	* the definition in vm_normal_page().
4030	*
4031	* Return: true if transhuge page-table entries should be considered special,
4032	* false otherwise.
4033	*/
4034	static inline bool vma_is_special_huge(const struct vm_area_struct *vma)
4035	{
4036	return vma_is_dax(vma) || (vma->vm_file &&
4037	(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
4038	}
4039
4040	#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
4041
4042	#if MAX_NUMNODES > 1
4043	void __init setup_nr_node_ids(void);
4044	#else
4045	static inline void setup_nr_node_ids(void) {}
4046	#endif
4047
4048	extern int memcmp_pages(struct page *page1, struct page *page2);
4049
4050	static inline int pages_identical(struct page *page1, struct page *page2)
4051	{
4052	return !memcmp_pages(page1, page2);
4053	}
4054
4055	#ifdef CONFIG_MAPPING_DIRTY_HELPERS
4056	unsigned long clean_record_shared_mapping_range(struct address_space *mapping,
4057	pgoff_t first_index, pgoff_t nr,
4058	pgoff_t bitmap_pgoff,
4059	unsigned long *bitmap,
4060	pgoff_t *start,
4061	pgoff_t *end);
4062
4063	unsigned long wp_shared_mapping_range(struct address_space *mapping,
4064	pgoff_t first_index, pgoff_t nr);
4065	#endif
4066
4067	extern int sysctl_nr_trim_pages;
4068
4069	#ifdef CONFIG_PRINTK
4070	void mem_dump_obj(void *object);
4071	#else
4072	static inline void mem_dump_obj(void *object) {}
4073	#endif
4074
4075	/**
4076	* seal_check_write - Check for F_SEAL_WRITE or F_SEAL_FUTURE_WRITE flags and
4077	* handle them.
4078	* @seals: the seals to check
4079	* @vma: the vma to operate on
4080	*
4081	* Check whether F_SEAL_WRITE or F_SEAL_FUTURE_WRITE are set; if so, do proper
4082	* check/handling on the vma flags. Return 0 if check pass, or <0 for errors.
4083	*/
4084	static inline int seal_check_write(int seals, struct vm_area_struct *vma)
4085	{
4086	if (seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
4087	/*
4088	* New PROT_WRITE and MAP_SHARED mmaps are not allowed when
4089	* write seals are active.
4090	*/
4091	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
4092	return -EPERM;
4093
4094	/*
4095	* Since an F_SEAL_[FUTURE_]WRITE sealed memfd can be mapped as
4096	* MAP_SHARED and read-only, take care to not allow mprotect to
4097	* revert protections on such mappings. Do this only for shared
4098	* mappings. For private mappings, don't need to mask
4099	* VM_MAYWRITE as we still want them to be COW-writable.
4100	*/
4101	if (vma->vm_flags & VM_SHARED)
4102	vm_flags_clear(vma, VM_MAYWRITE);
4103	}
4104
4105	return 0;
4106	}
4107
4108	#ifdef CONFIG_ANON_VMA_NAME
4109	int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
4110	unsigned long len_in,
4111	struct anon_vma_name *anon_name);
4112	#else
4113	static inline int
4114	madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
4115	unsigned long len_in, struct anon_vma_name *anon_name) {
4116	return 0;
4117	}
4118	#endif
4119
4120	#ifdef CONFIG_UNACCEPTED_MEMORY
4121
4122	bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end);
4123	void accept_memory(phys_addr_t start, phys_addr_t end);
4124
4125	#else
4126
4127	static inline bool range_contains_unaccepted_memory(phys_addr_t start,
4128	phys_addr_t end)
4129	{
4130	return false;
4131	}
4132
4133	static inline void accept_memory(phys_addr_t start, phys_addr_t end)
4134	{
4135	}
4136
4137	#endif
4138
4139	static inline bool pfn_is_unaccepted_memory(unsigned long pfn)
4140	{
4141	phys_addr_t paddr = pfn << PAGE_SHIFT;
4142
4143	return range_contains_unaccepted_memory(start: paddr, end: paddr + PAGE_SIZE);
4144	}
4145
4146	#endif /* _LINUX_MM_H */
4147