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/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_RMAP_H #define _LINUX_RMAP_H /* * Declarations for Reverse Mapping functions in mm/rmap.c */ #include <linux/list.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/rwsem.h> #include <linux/memcontrol.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/memremap.h> /* * The anon_vma heads a list of private "related" vmas, to scan if * an anonymous page pointing to this anon_vma needs to be unmapped: * the vmas on the list will be related by forking, or by splitting. * * Since vmas come and go as they are split and merged (particularly * in mprotect), the mapping field of an anonymous page cannot point * directly to a vma: instead it points to an anon_vma, on whose list * the related vmas can be easily linked or unlinked. * * After unlinking the last vma on the list, we must garbage collect * the anon_vma object itself: we're guaranteed no page can be * pointing to this anon_vma once its vma list is empty. */ struct anon_vma { struct anon_vma *root; /* Root of this anon_vma tree */ struct rw_semaphore rwsem; /* W: modification, R: walking the list */ /* * The refcount is taken on an anon_vma when there is no * guarantee that the vma of page tables will exist for * the duration of the operation. A caller that takes * the reference is responsible for clearing up the * anon_vma if they are the last user on release */ atomic_t refcount; /* * Count of child anon_vmas. Equals to the count of all anon_vmas that * have ->parent pointing to this one, including itself. * * This counter is used for making decision about reusing anon_vma * instead of forking new one. See comments in function anon_vma_clone. */ unsigned long num_children; /* Count of VMAs whose ->anon_vma pointer points to this object. */ unsigned long num_active_vmas; struct anon_vma *parent; /* Parent of this anon_vma */ /* * NOTE: the LSB of the rb_root.rb_node is set by * mm_take_all_locks() _after_ taking the above lock. So the * rb_root must only be read/written after taking the above lock * to be sure to see a valid next pointer. The LSB bit itself * is serialized by a system wide lock only visible to * mm_take_all_locks() (mm_all_locks_mutex). */ /* Interval tree of private "related" vmas */ struct rb_root_cached rb_root; }; /* * The copy-on-write semantics of fork mean that an anon_vma * can become associated with multiple processes. Furthermore, * each child process will have its own anon_vma, where new * pages for that process are instantiated. * * This structure allows us to find the anon_vmas associated * with a VMA, or the VMAs associated with an anon_vma. * The "same_vma" list contains the anon_vma_chains linking * all the anon_vmas associated with this VMA. * The "rb" field indexes on an interval tree the anon_vma_chains * which link all the VMAs associated with this anon_vma. */ struct anon_vma_chain { struct vm_area_struct *vma; struct anon_vma *anon_vma; struct list_head same_vma; /* locked by mmap_lock & page_table_lock */ struct rb_node rb; /* locked by anon_vma->rwsem */ unsigned long rb_subtree_last; #ifdef CONFIG_DEBUG_VM_RB unsigned long cached_vma_start, cached_vma_last; #endif }; enum ttu_flags { TTU_SPLIT_HUGE_PMD = 0x4, /* split huge PMD if any */ TTU_IGNORE_MLOCK = 0x8, /* ignore mlock */ TTU_SYNC = 0x10, /* avoid racy checks with PVMW_SYNC */ TTU_HWPOISON = 0x20, /* do convert pte to hwpoison entry */ TTU_BATCH_FLUSH = 0x40, /* Batch TLB flushes where possible * and caller guarantees they will * do a final flush if necessary */ TTU_RMAP_LOCKED = 0x80, /* do not grab rmap lock: * caller holds it */ }; #ifdef CONFIG_MMU static inline void get_anon_vma(struct anon_vma *anon_vma) { atomic_inc(&anon_vma->refcount); } void __put_anon_vma(struct anon_vma *anon_vma); static inline void put_anon_vma(struct anon_vma *anon_vma) { if (atomic_dec_and_test(&anon_vma->refcount)) __put_anon_vma(anon_vma); } static inline void anon_vma_lock_write(struct anon_vma *anon_vma) { down_write(&anon_vma->root->rwsem); } static inline int anon_vma_trylock_write(struct anon_vma *anon_vma) { return down_write_trylock(&anon_vma->root->rwsem); } static inline void anon_vma_unlock_write(struct anon_vma *anon_vma) { up_write(&anon_vma->root->rwsem); } static inline void anon_vma_lock_read(struct anon_vma *anon_vma) { down_read(&anon_vma->root->rwsem); } static inline int anon_vma_trylock_read(struct anon_vma *anon_vma) { return down_read_trylock(&anon_vma->root->rwsem); } static inline void anon_vma_unlock_read(struct anon_vma *anon_vma) { up_read(&anon_vma->root->rwsem); } /* * anon_vma helper functions. */ void anon_vma_init(void); /* create anon_vma_cachep */ int __anon_vma_prepare(struct vm_area_struct *); void unlink_anon_vmas(struct vm_area_struct *); int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); static inline int anon_vma_prepare(struct vm_area_struct *vma) { if (likely(vma->anon_vma)) return 0; return __anon_vma_prepare(vma); } static inline void anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next) { VM_BUG_ON_VMA(vma->anon_vma != next->anon_vma, vma); unlink_anon_vmas(next); } struct anon_vma *folio_get_anon_vma(const struct folio *folio); /* RMAP flags, currently only relevant for some anon rmap operations. */ typedef int __bitwise rmap_t; /* * No special request: A mapped anonymous (sub)page is possibly shared between * processes. */ #define RMAP_NONE ((__force rmap_t)0) /* The anonymous (sub)page is exclusive to a single process. */ #define RMAP_EXCLUSIVE ((__force rmap_t)BIT(0)) /* * Internally, we're using an enum to specify the granularity. We make the * compiler emit specialized code for each granularity. */ enum rmap_level { RMAP_LEVEL_PTE = 0, RMAP_LEVEL_PMD, }; static inline void __folio_rmap_sanity_checks(const struct folio *folio, const struct page *page, int nr_pages, enum rmap_level level) { /* hugetlb folios are handled separately. */ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); /* When (un)mapping zeropages, we should never touch ref+mapcount. */ VM_WARN_ON_FOLIO(is_zero_folio(folio), folio); /* * TODO: we get driver-allocated folios that have nothing to do with * the rmap using vm_insert_page(); therefore, we cannot assume that * folio_test_large_rmappable() holds for large folios. We should * handle any desired mapcount+stats accounting for these folios in * VM_MIXEDMAP VMAs separately, and then sanity-check here that * we really only get rmappable folios. */ VM_WARN_ON_ONCE(nr_pages <= 0); VM_WARN_ON_FOLIO(page_folio(page) != folio, folio); VM_WARN_ON_FOLIO(page_folio(page + nr_pages - 1) != folio, folio); switch (level) { case RMAP_LEVEL_PTE: break; case RMAP_LEVEL_PMD: /* * We don't support folios larger than a single PMD yet. So * when RMAP_LEVEL_PMD is set, we assume that we are creating * a single "entire" mapping of the folio. */ VM_WARN_ON_FOLIO(folio_nr_pages(folio) != HPAGE_PMD_NR, folio); VM_WARN_ON_FOLIO(nr_pages != HPAGE_PMD_NR, folio); break; default: VM_WARN_ON_ONCE(true); } } /* * rmap interfaces called when adding or removing pte of page */ void folio_move_anon_rmap(struct folio *, struct vm_area_struct *); void folio_add_anon_rmap_ptes(struct folio *, struct page *, int nr_pages, struct vm_area_struct *, unsigned long address, rmap_t flags); #define folio_add_anon_rmap_pte(folio, page, vma, address, flags) \ folio_add_anon_rmap_ptes(folio, page, 1, vma, address, flags) void folio_add_anon_rmap_pmd(struct folio *, struct page *, struct vm_area_struct *, unsigned long address, rmap_t flags); void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address, rmap_t flags); void folio_add_file_rmap_ptes(struct folio *, struct page *, int nr_pages, struct vm_area_struct *); #define folio_add_file_rmap_pte(folio, page, vma) \ folio_add_file_rmap_ptes(folio, page, 1, vma) void folio_add_file_rmap_pmd(struct folio *, struct page *, struct vm_area_struct *); void folio_remove_rmap_ptes(struct folio *, struct page *, int nr_pages, struct vm_area_struct *); #define folio_remove_rmap_pte(folio, page, vma) \ folio_remove_rmap_ptes(folio, page, 1, vma) void folio_remove_rmap_pmd(struct folio *, struct page *, struct vm_area_struct *); void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address, rmap_t flags); void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); /* See folio_try_dup_anon_rmap_*() */ static inline int hugetlb_try_dup_anon_rmap(struct folio *folio, struct vm_area_struct *vma) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); if (PageAnonExclusive(&folio->page)) { if (unlikely(folio_needs_cow_for_dma(vma, folio))) return -EBUSY; ClearPageAnonExclusive(&folio->page); } atomic_inc(&folio->_entire_mapcount); atomic_inc(&folio->_large_mapcount); return 0; } /* See folio_try_share_anon_rmap_*() */ static inline int hugetlb_try_share_anon_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); VM_WARN_ON_FOLIO(!PageAnonExclusive(&folio->page), folio); /* Paired with the memory barrier in try_grab_folio(). */ if (IS_ENABLED(CONFIG_HAVE_GUP_FAST)) smp_mb(); if (unlikely(folio_maybe_dma_pinned(folio))) return -EBUSY; ClearPageAnonExclusive(&folio->page); /* * This is conceptually a smp_wmb() paired with the smp_rmb() in * gup_must_unshare(). */ if (IS_ENABLED(CONFIG_HAVE_GUP_FAST)) smp_mb__after_atomic(); return 0; } static inline void hugetlb_add_file_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); atomic_inc(&folio->_entire_mapcount); atomic_inc(&folio->_large_mapcount); } static inline void hugetlb_remove_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); atomic_dec(&folio->_entire_mapcount); atomic_dec(&folio->_large_mapcount); } static __always_inline void __folio_dup_file_rmap(struct folio *folio, struct page *page, int nr_pages, enum rmap_level level) { const int orig_nr_pages = nr_pages; __folio_rmap_sanity_checks(folio, page, nr_pages, level); switch (level) { case RMAP_LEVEL_PTE: if (!folio_test_large(folio)) { atomic_inc(&folio->_mapcount); break; } do { atomic_inc(&page->_mapcount); } while (page++, --nr_pages > 0); atomic_add(orig_nr_pages, &folio->_large_mapcount); break; case RMAP_LEVEL_PMD: atomic_inc(&folio->_entire_mapcount); atomic_inc(&folio->_large_mapcount); break; } } /** * folio_dup_file_rmap_ptes - duplicate PTE mappings of a page range of a folio * @folio: The folio to duplicate the mappings of * @page: The first page to duplicate the mappings of * @nr_pages: The number of pages of which the mapping will be duplicated * * The page range of the folio is defined by [page, page + nr_pages) * * The caller needs to hold the page table lock. */ static inline void folio_dup_file_rmap_ptes(struct folio *folio, struct page *page, int nr_pages) { __folio_dup_file_rmap(folio, page, nr_pages, RMAP_LEVEL_PTE); } static __always_inline void folio_dup_file_rmap_pte(struct folio *folio, struct page *page) { __folio_dup_file_rmap(folio, page, 1, RMAP_LEVEL_PTE); } /** * folio_dup_file_rmap_pmd - duplicate a PMD mapping of a page range of a folio * @folio: The folio to duplicate the mapping of * @page: The first page to duplicate the mapping of * * The page range of the folio is defined by [page, page + HPAGE_PMD_NR) * * The caller needs to hold the page table lock. */ static inline void folio_dup_file_rmap_pmd(struct folio *folio, struct page *page) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE __folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, RMAP_LEVEL_PTE); #else WARN_ON_ONCE(true); #endif } static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *src_vma, enum rmap_level level) { const int orig_nr_pages = nr_pages; bool maybe_pinned; int i; VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); __folio_rmap_sanity_checks(folio, page, nr_pages, level); /* * If this folio may have been pinned by the parent process, * don't allow to duplicate the mappings but instead require to e.g., * copy the subpage immediately for the child so that we'll always * guarantee the pinned folio won't be randomly replaced in the * future on write faults. */ maybe_pinned = likely(!folio_is_device_private(folio)) && unlikely(folio_needs_cow_for_dma(src_vma, folio)); /* * No need to check+clear for already shared PTEs/PMDs of the * folio. But if any page is PageAnonExclusive, we must fallback to * copying if the folio maybe pinned. */ switch (level) { case RMAP_LEVEL_PTE: if (unlikely(maybe_pinned)) { for (i = 0; i < nr_pages; i++) if (PageAnonExclusive(page + i)) return -EBUSY; } if (!folio_test_large(folio)) { if (PageAnonExclusive(page)) ClearPageAnonExclusive(page); atomic_inc(&folio->_mapcount); break; } do { if (PageAnonExclusive(page)) ClearPageAnonExclusive(page); atomic_inc(&page->_mapcount); } while (page++, --nr_pages > 0); atomic_add(orig_nr_pages, &folio->_large_mapcount); break; case RMAP_LEVEL_PMD: if (PageAnonExclusive(page)) { if (unlikely(maybe_pinned)) return -EBUSY; ClearPageAnonExclusive(page); } atomic_inc(&folio->_entire_mapcount); atomic_inc(&folio->_large_mapcount); break; } return 0; } /** * folio_try_dup_anon_rmap_ptes - try duplicating PTE mappings of a page range * of a folio * @folio: The folio to duplicate the mappings of * @page: The first page to duplicate the mappings of * @nr_pages: The number of pages of which the mapping will be duplicated * @src_vma: The vm area from which the mappings are duplicated * * The page range of the folio is defined by [page, page + nr_pages) * * The caller needs to hold the page table lock and the * vma->vma_mm->write_protect_seq. * * Duplicating the mappings can only fail if the folio may be pinned; device * private folios cannot get pinned and consequently this function cannot fail * for them. * * If duplicating the mappings succeeded, the duplicated PTEs have to be R/O in * the parent and the child. They must *not* be writable after this call * succeeded. * * Returns 0 if duplicating the mappings succeeded. Returns -EBUSY otherwise. */ static inline int folio_try_dup_anon_rmap_ptes(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *src_vma) { return __folio_try_dup_anon_rmap(folio, page, nr_pages, src_vma, RMAP_LEVEL_PTE); } static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio, struct page *page, struct vm_area_struct *src_vma) { return __folio_try_dup_anon_rmap(folio, page, 1, src_vma, RMAP_LEVEL_PTE); } /** * folio_try_dup_anon_rmap_pmd - try duplicating a PMD mapping of a page range * of a folio * @folio: The folio to duplicate the mapping of * @page: The first page to duplicate the mapping of * @src_vma: The vm area from which the mapping is duplicated * * The page range of the folio is defined by [page, page + HPAGE_PMD_NR) * * The caller needs to hold the page table lock and the * vma->vma_mm->write_protect_seq. * * Duplicating the mapping can only fail if the folio may be pinned; device * private folios cannot get pinned and consequently this function cannot fail * for them. * * If duplicating the mapping succeeds, the duplicated PMD has to be R/O in * the parent and the child. They must *not* be writable after this call * succeeded. * * Returns 0 if duplicating the mapping succeeded. Returns -EBUSY otherwise. */ static inline int folio_try_dup_anon_rmap_pmd(struct folio *folio, struct page *page, struct vm_area_struct *src_vma) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE return __folio_try_dup_anon_rmap(folio, page, HPAGE_PMD_NR, src_vma, RMAP_LEVEL_PMD); #else WARN_ON_ONCE(true); return -EBUSY; #endif } static __always_inline int __folio_try_share_anon_rmap(struct folio *folio, struct page *page, int nr_pages, enum rmap_level level) { VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); VM_WARN_ON_FOLIO(!PageAnonExclusive(page), folio); __folio_rmap_sanity_checks(folio, page, nr_pages, level); /* device private folios cannot get pinned via GUP. */ if (unlikely(folio_is_device_private(folio))) { ClearPageAnonExclusive(page); return 0; } /* * We have to make sure that when we clear PageAnonExclusive, that * the page is not pinned and that concurrent GUP-fast won't succeed in * concurrently pinning the page. * * Conceptually, PageAnonExclusive clearing consists of: * (A1) Clear PTE * (A2) Check if the page is pinned; back off if so. * (A3) Clear PageAnonExclusive * (A4) Restore PTE (optional, but certainly not writable) * * When clearing PageAnonExclusive, we cannot possibly map the page * writable again, because anon pages that may be shared must never * be writable. So in any case, if the PTE was writable it cannot * be writable anymore afterwards and there would be a PTE change. Only * if the PTE wasn't writable, there might not be a PTE change. * * Conceptually, GUP-fast pinning of an anon page consists of: * (B1) Read the PTE * (B2) FOLL_WRITE: check if the PTE is not writable; back off if so. * (B3) Pin the mapped page * (B4) Check if the PTE changed by re-reading it; back off if so. * (B5) If the original PTE is not writable, check if * PageAnonExclusive is not set; back off if so. * * If the PTE was writable, we only have to make sure that GUP-fast * observes a PTE change and properly backs off. * * If the PTE was not writable, we have to make sure that GUP-fast either * detects a (temporary) PTE change or that PageAnonExclusive is cleared * and properly backs off. * * Consequently, when clearing PageAnonExclusive(), we have to make * sure that (A1), (A2)/(A3) and (A4) happen in the right memory * order. In GUP-fast pinning code, we have to make sure that (B3),(B4) * and (B5) happen in the right memory order. * * We assume that there might not be a memory barrier after * clearing/invalidating the PTE (A1) and before restoring the PTE (A4), * so we use explicit ones here. */ /* Paired with the memory barrier in try_grab_folio(). */ if (IS_ENABLED(CONFIG_HAVE_GUP_FAST)) smp_mb(); if (unlikely(folio_maybe_dma_pinned(folio))) return -EBUSY; ClearPageAnonExclusive(page); /* * This is conceptually a smp_wmb() paired with the smp_rmb() in * gup_must_unshare(). */ if (IS_ENABLED(CONFIG_HAVE_GUP_FAST)) smp_mb__after_atomic(); return 0; } /** * folio_try_share_anon_rmap_pte - try marking an exclusive anonymous page * mapped by a PTE possibly shared to prepare * for KSM or temporary unmapping * @folio: The folio to share a mapping of * @page: The mapped exclusive page * * The caller needs to hold the page table lock and has to have the page table * entries cleared/invalidated. * * This is similar to folio_try_dup_anon_rmap_pte(), however, not used during * fork() to duplicate mappings, but instead to prepare for KSM or temporarily * unmapping parts of a folio (swap, migration) via folio_remove_rmap_pte(). * * Marking the mapped page shared can only fail if the folio maybe pinned; * device private folios cannot get pinned and consequently this function cannot * fail. * * Returns 0 if marking the mapped page possibly shared succeeded. Returns * -EBUSY otherwise. */ static inline int folio_try_share_anon_rmap_pte(struct folio *folio, struct page *page) { return __folio_try_share_anon_rmap(folio, page, 1, RMAP_LEVEL_PTE); } /** * folio_try_share_anon_rmap_pmd - try marking an exclusive anonymous page * range mapped by a PMD possibly shared to * prepare for temporary unmapping * @folio: The folio to share the mapping of * @page: The first page to share the mapping of * * The page range of the folio is defined by [page, page + HPAGE_PMD_NR) * * The caller needs to hold the page table lock and has to have the page table * entries cleared/invalidated. * * This is similar to folio_try_dup_anon_rmap_pmd(), however, not used during * fork() to duplicate a mapping, but instead to prepare for temporarily * unmapping parts of a folio (swap, migration) via folio_remove_rmap_pmd(). * * Marking the mapped pages shared can only fail if the folio maybe pinned; * device private folios cannot get pinned and consequently this function cannot * fail. * * Returns 0 if marking the mapped pages possibly shared succeeded. Returns * -EBUSY otherwise. */ static inline int folio_try_share_anon_rmap_pmd(struct folio *folio, struct page *page) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE return __folio_try_share_anon_rmap(folio, page, HPAGE_PMD_NR, RMAP_LEVEL_PMD); #else WARN_ON_ONCE(true); return -EBUSY; #endif } /* * Called from mm/vmscan.c to handle paging out */ int folio_referenced(struct folio *, int is_locked, struct mem_cgroup *memcg, unsigned long *vm_flags); void try_to_migrate(struct folio *folio, enum ttu_flags flags); void try_to_unmap(struct folio *, enum ttu_flags flags); int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, unsigned long end, struct page **pages, void *arg); /* Avoid racy checks */ #define PVMW_SYNC (1 << 0) /* Look for migration entries rather than present PTEs */ #define PVMW_MIGRATION (1 << 1) struct page_vma_mapped_walk { unsigned long pfn; unsigned long nr_pages; pgoff_t pgoff; struct vm_area_struct *vma; unsigned long address; pmd_t *pmd; pte_t *pte; spinlock_t *ptl; unsigned int flags; }; #define DEFINE_FOLIO_VMA_WALK(name, _folio, _vma, _address, _flags) \ struct page_vma_mapped_walk name = { \ .pfn = folio_pfn(_folio), \ .nr_pages = folio_nr_pages(_folio), \ .pgoff = folio_pgoff(_folio), \ .vma = _vma, \ .address = _address, \ .flags = _flags, \ } static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw) { /* HugeTLB pte is set to the relevant page table entry without pte_mapped. */ if (pvmw->pte && !is_vm_hugetlb_page(pvmw->vma)) pte_unmap(pvmw->pte); if (pvmw->ptl) spin_unlock(pvmw->ptl); } /** * page_vma_mapped_walk_restart - Restart the page table walk. * @pvmw: Pointer to struct page_vma_mapped_walk. * * It restarts the page table walk when changes occur in the page * table, such as splitting a PMD. Ensures that the PTL held during * the previous walk is released and resets the state to allow for * a new walk starting at the current address stored in pvmw->address. */ static inline void page_vma_mapped_walk_restart(struct page_vma_mapped_walk *pvmw) { WARN_ON_ONCE(!pvmw->pmd && !pvmw->pte); if (likely(pvmw->ptl)) spin_unlock(pvmw->ptl); else WARN_ON_ONCE(1); pvmw->ptl = NULL; pvmw->pmd = NULL; pvmw->pte = NULL; } bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw); unsigned long page_address_in_vma(const struct folio *folio, const struct page *, const struct vm_area_struct *); /* * Cleans the PTEs of shared mappings. * (and since clean PTEs should also be readonly, write protects them too) * * returns the number of cleaned PTEs. */ int folio_mkclean(struct folio *); int pfn_mkclean_range(unsigned long pfn, unsigned long nr_pages, pgoff_t pgoff, struct vm_area_struct *vma); enum rmp_flags { RMP_LOCKED = 1 << 0, RMP_USE_SHARED_ZEROPAGE = 1 << 1, }; void remove_migration_ptes(struct folio *src, struct folio *dst, int flags); /* * rmap_walk_control: To control rmap traversing for specific needs * * arg: passed to rmap_one() and invalid_vma() * try_lock: bail out if the rmap lock is contended * contended: indicate the rmap traversal bailed out due to lock contention * rmap_one: executed on each vma where page is mapped * done: for checking traversing termination condition * anon_lock: for getting anon_lock by optimized way rather than default * invalid_vma: for skipping uninterested vma */ struct rmap_walk_control { void *arg; bool try_lock; bool contended; /* * Return false if page table scanning in rmap_walk should be stopped. * Otherwise, return true. */ bool (*rmap_one)(struct folio *folio, struct vm_area_struct *vma, unsigned long addr, void *arg); int (*done)(struct folio *folio); struct anon_vma *(*anon_lock)(const struct folio *folio, struct rmap_walk_control *rwc); bool (*invalid_vma)(struct vm_area_struct *vma, void *arg); }; void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc); void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc); struct anon_vma *folio_lock_anon_vma_read(const struct folio *folio, struct rmap_walk_control *rwc); #else /* !CONFIG_MMU */ #define anon_vma_init() do {} while (0) #define anon_vma_prepare(vma) (0) static inline int folio_referenced(struct folio *folio, int is_locked, struct mem_cgroup *memcg, unsigned long *vm_flags) { *vm_flags = 0; return 0; } static inline void try_to_unmap(struct folio *folio, enum ttu_flags flags) { } static inline int folio_mkclean(struct folio *folio) { return 0; } #endif /* CONFIG_MMU */ #endif /* _LINUX_RMAP_H */