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 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Macros for manipulating and testing page->flags
  */
 
 #ifndef PAGE_FLAGS_H
 #define PAGE_FLAGS_H
 
 #include <linux/types.h>
 #include <linux/bug.h>
 #include <linux/mmdebug.h>
 #ifndef __GENERATING_BOUNDS_H
 #include <linux/mm_types.h>
 #include <generated/bounds.h>
 #endif /* !__GENERATING_BOUNDS_H */
 
 /*
  * Various page->flags bits:
  *
  * PG_reserved is set for special pages. The "struct page" of such a page
  * should in general not be touched (e.g. set dirty) except by its owner.
  * Pages marked as PG_reserved include:
  * - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS,
  *   initrd, HW tables)
  * - Pages reserved or allocated early during boot (before the page allocator
  *   was initialized). This includes (depending on the architecture) the
  *   initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much
  *   much more. Once (if ever) freed, PG_reserved is cleared and they will
  *   be given to the page allocator.
  * - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying
  *   to read/write these pages might end badly. Don't touch!
  * - The zero page(s)
  * - Pages not added to the page allocator when onlining a section because
  *   they were excluded via the online_page_callback() or because they are
  *   PG_hwpoison.
  * - Pages allocated in the context of kexec/kdump (loaded kernel image,
  *   control pages, vmcoreinfo)
  * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are
  *   not marked PG_reserved (as they might be in use by somebody else who does
  *   not respect the caching strategy).
  * - Pages part of an offline section (struct pages of offline sections should
  *   not be trusted as they will be initialized when first onlined).
  * - MCA pages on ia64
  * - Pages holding CPU notes for POWER Firmware Assisted Dump
  * - Device memory (e.g. PMEM, DAX, HMM)
  * Some PG_reserved pages will be excluded from the hibernation image.
  * PG_reserved does in general not hinder anybody from dumping or swapping
  * and is no longer required for remap_pfn_range(). ioremap might require it.
  * Consequently, PG_reserved for a page mapped into user space can indicate
  * the zero page, the vDSO, MMIO pages or device memory.
  *
  * The PG_private bitflag is set on pagecache pages if they contain filesystem
  * specific data (which is normally at page->private). It can be used by
  * private allocations for its own usage.
  *
  * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
  * and cleared when writeback _starts_ or when read _completes_. PG_writeback
  * is set before writeback starts and cleared when it finishes.
  *
  * PG_locked also pins a page in pagecache, and blocks truncation of the file
  * while it is held.
  *
  * page_waitqueue(page) is a wait queue of all tasks waiting for the page
  * to become unlocked.
  *
  * PG_swapbacked is set when a page uses swap as a backing storage.  This are
  * usually PageAnon or shmem pages but please note that even anonymous pages
  * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
  * a result of MADV_FREE).
  *
  * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
  * file-backed pagecache (see mm/vmscan.c).
  *
  * PG_error is set to indicate that an I/O error occurred on this page.
  *
  * PG_arch_1 is an architecture specific page state bit.  The generic code
  * guarantees that this bit is cleared for a page when it first is entered into
  * the page cache.
  *
  * PG_hwpoison indicates that a page got corrupted in hardware and contains
  * data with incorrect ECC bits that triggered a machine check. Accessing is
  * not safe since it may cause another machine check. Don't touch!
  */
 
 /*
  * Don't use the pageflags directly.  Use the PageFoo macros.
  *
  * The page flags field is split into two parts, the main flags area
  * which extends from the low bits upwards, and the fields area which
  * extends from the high bits downwards.
  *
  *  | FIELD | ... | FLAGS |
  *  N-1           ^       0
  *               (NR_PAGEFLAGS)
  *
  * The fields area is reserved for fields mapping zone, node (for NUMA) and
  * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
  * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
  */
 enum pageflags {
     PG_locked,      /* Page is locked. Don't touch. */
     PG_referenced,
     PG_uptodate,
     PG_dirty,
     PG_lru,
     PG_active,
     PG_workingset,
     PG_waiters,     /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
     PG_error,
     PG_slab,
     PG_owner_priv_1,    /* Owner use. If pagecache, fs may use*/
     PG_arch_1,
     PG_reserved,
     PG_private,     /* If pagecache, has fs-private data */
     PG_private_2,       /* If pagecache, has fs aux data */
     PG_writeback,       /* Page is under writeback */
     PG_head,        /* A head page */
     PG_mappedtodisk,    /* Has blocks allocated on-disk */
     PG_reclaim,     /* To be reclaimed asap */
     PG_swapbacked,      /* Page is backed by RAM/swap */
     PG_unevictable,     /* Page is "unevictable"  */
 #ifdef CONFIG_MMU
     PG_mlocked,     /* Page is vma mlocked */
 #endif
 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
     PG_uncached,        /* Page has been mapped as uncached */
 #endif
 #ifdef CONFIG_MEMORY_FAILURE
     PG_hwpoison,        /* hardware poisoned page. Don't touch */
 #endif
 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
     PG_young,
     PG_idle,
 #endif
 #ifdef CONFIG_64BIT
     PG_arch_2,
 #endif
 #ifdef CONFIG_KASAN_HW_TAGS
     PG_skip_kasan_poison,
 #endif
     __NR_PAGEFLAGS,
 
     PG_readahead = PG_reclaim,
 
     /*
      * Depending on the way an anonymous folio can be mapped into a page
      * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped
      * THP), PG_anon_exclusive may be set only for the head page or for
      * tail pages of an anonymous folio. For now, we only expect it to be
      * set on tail pages for PTE-mapped THP.
      */
     PG_anon_exclusive = PG_mappedtodisk,
 
     /* Filesystems */
     PG_checked = PG_owner_priv_1,
 
     /* SwapBacked */
     PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
 
     /* Two page bits are conscripted by FS-Cache to maintain local caching
      * state.  These bits are set on pages belonging to the netfs's inodes
      * when those inodes are being locally cached.
      */
     PG_fscache = PG_private_2,  /* page backed by cache */
 
     /* XEN */
     /* Pinned in Xen as a read-only pagetable page. */
     PG_pinned = PG_owner_priv_1,
     /* Pinned as part of domain save (see xen_mm_pin_all()). */
     PG_savepinned = PG_dirty,
     /* Has a grant mapping of another (foreign) domain's page. */
     PG_foreign = PG_owner_priv_1,
     /* Remapped by swiotlb-xen. */
     PG_xen_remapped = PG_owner_priv_1,
 
     /* SLOB */
     PG_slob_free = PG_private,
 
     /* Compound pages. Stored in first tail page's flags */
     PG_double_map = PG_workingset,
 
 #ifdef CONFIG_MEMORY_FAILURE
     /*
      * Compound pages. Stored in first tail page's flags.
      * Indicates that at least one subpage is hwpoisoned in the
      * THP.
      */
     PG_has_hwpoisoned = PG_error,
 #endif
 
     /* non-lru isolated movable page */
     PG_isolated = PG_reclaim,
 
     /* Only valid for buddy pages. Used to track pages that are reported */
     PG_reported = PG_uptodate,
 
 #ifdef CONFIG_MEMORY_HOTPLUG
     /* For self-hosted memmap pages */
     PG_vmemmap_self_hosted = PG_owner_priv_1,
 #endif
 };
 
 #define PAGEFLAGS_MASK      ((1UL << NR_PAGEFLAGS) - 1)
 
 #ifndef __GENERATING_BOUNDS_H
 
 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
 
 /*
  * Return the real head page struct iff the @page is a fake head page, otherwise
  * return the @page itself. See Documentation/mm/vmemmap_dedup.rst.
  */
 static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
 {
     if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key))
         return page;
 
     /*
      * Only addresses aligned with PAGE_SIZE of struct page may be fake head
      * struct page. The alignment check aims to avoid access the fields (
      * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly)
      * cold cacheline in some cases.
      */
     if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) &&
         test_bit(PG_head, &page->flags)) {
         /*
          * We can safely access the field of the @page[1] with PG_head
          * because the @page is a compound page composed with at least
          * two contiguous pages.
          */
         unsigned long head = READ_ONCE(page[1].compound_head);
 
         if (likely(head & 1))
             return (const struct page *)(head - 1);
     }
     return page;
 }
 #else
 static inline const struct page *page_fixed_fake_head(const struct page *page)
 {
     return page;
 }
 #endif
 
 static __always_inline int page_is_fake_head(struct page *page)
 {
     return page_fixed_fake_head(page) != page;
 }
 
 static inline unsigned long _compound_head(const struct page *page)
 {
     unsigned long head = READ_ONCE(page->compound_head);
 
     if (unlikely(head & 1))
         return head - 1;
     return (unsigned long)page_fixed_fake_head(page);
 }
 
 #define compound_head(page) ((typeof(page))_compound_head(page))
 
 /**
  * page_folio - Converts from page to folio.
  * @p: The page.
  *
  * Every page is part of a folio.  This function cannot be called on a
  * NULL pointer.
  *
  * Context: No reference, nor lock is required on @page.  If the caller
  * does not hold a reference, this call may race with a folio split, so
  * it should re-check the folio still contains this page after gaining
  * a reference on the folio.
  * Return: The folio which contains this page.
  */
 #define page_folio(p)       (_Generic((p),              \
     const struct page *:    (const struct folio *)_compound_head(p), \
     struct page *:      (struct folio *)_compound_head(p)))
 
 /**
  * folio_page - Return a page from a folio.
  * @folio: The folio.
  * @n: The page number to return.
  *
  * @n is relative to the start of the folio.  This function does not
  * check that the page number lies within @folio; the caller is presumed
  * to have a reference to the page.
  */
 #define folio_page(folio, n)    nth_page(&(folio)->page, n)
 
 static __always_inline int PageTail(struct page *page)
 {
     return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
 }
 
 static __always_inline int PageCompound(struct page *page)
 {
     return test_bit(PG_head, &page->flags) ||
            READ_ONCE(page->compound_head) & 1;
 }
 
 #define PAGE_POISON_PATTERN -1l
 static inline int PagePoisoned(const struct page *page)
 {
     return READ_ONCE(page->flags) == PAGE_POISON_PATTERN;
 }
 
 #ifdef CONFIG_DEBUG_VM
 void page_init_poison(struct page *page, size_t size);
 #else
 static inline void page_init_poison(struct page *page, size_t size)
 {
 }
 #endif
 
 static unsigned long *folio_flags(struct folio *folio, unsigned n)
 {
     struct page *page = &folio->page;
 
     VM_BUG_ON_PGFLAGS(PageTail(page), page);
     VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
     return &page[n].flags;
 }
 
 /*
  * Page flags policies wrt compound pages
  *
  * PF_POISONED_CHECK
  *     check if this struct page poisoned/uninitialized
  *
  * PF_ANY:
  *     the page flag is relevant for small, head and tail pages.
  *
  * PF_HEAD:
  *     for compound page all operations related to the page flag applied to
  *     head page.
  *
  * PF_ONLY_HEAD:
  *     for compound page, callers only ever operate on the head page.
  *
  * PF_NO_TAIL:
  *     modifications of the page flag must be done on small or head pages,
  *     checks can be done on tail pages too.
  *
  * PF_NO_COMPOUND:
  *     the page flag is not relevant for compound pages.
  *
  * PF_SECOND:
  *     the page flag is stored in the first tail page.
  */
 #define PF_POISONED_CHECK(page) ({                  \
         VM_BUG_ON_PGFLAGS(PagePoisoned(page), page);        \
         page; })
 #define PF_ANY(page, enforce)   PF_POISONED_CHECK(page)
 #define PF_HEAD(page, enforce)  PF_POISONED_CHECK(compound_head(page))
 #define PF_ONLY_HEAD(page, enforce) ({                  \
         VM_BUG_ON_PGFLAGS(PageTail(page), page);        \
         PF_POISONED_CHECK(page); })
 #define PF_NO_TAIL(page, enforce) ({                    \
         VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
         PF_POISONED_CHECK(compound_head(page)); })
 #define PF_NO_COMPOUND(page, enforce) ({                \
         VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
         PF_POISONED_CHECK(page); })
 #define PF_SECOND(page, enforce) ({                 \
         VM_BUG_ON_PGFLAGS(!PageHead(page), page);       \
         PF_POISONED_CHECK(&page[1]); })
 
 /* Which page is the flag stored in */
 #define FOLIO_PF_ANY        0
 #define FOLIO_PF_HEAD       0
 #define FOLIO_PF_ONLY_HEAD  0
 #define FOLIO_PF_NO_TAIL    0
 #define FOLIO_PF_NO_COMPOUND    0
 #define FOLIO_PF_SECOND     1
 
 /*
  * Macros to create function definitions for page flags
  */
 #define TESTPAGEFLAG(uname, lname, policy)              \
 static __always_inline bool folio_test_##lname(struct folio *folio) \
 { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }    \
 static __always_inline int Page##uname(struct page *page)       \
 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
 
 #define SETPAGEFLAG(uname, lname, policy)               \
 static __always_inline                          \
 void folio_set_##lname(struct folio *folio)             \
 { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }        \
 static __always_inline void SetPage##uname(struct page *page)       \
 { set_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define CLEARPAGEFLAG(uname, lname, policy)             \
 static __always_inline                          \
 void folio_clear_##lname(struct folio *folio)               \
 { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }      \
 static __always_inline void ClearPage##uname(struct page *page)     \
 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define __SETPAGEFLAG(uname, lname, policy)             \
 static __always_inline                          \
 void __folio_set_##lname(struct folio *folio)               \
 { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }      \
 static __always_inline void __SetPage##uname(struct page *page)     \
 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define __CLEARPAGEFLAG(uname, lname, policy)               \
 static __always_inline                          \
 void __folio_clear_##lname(struct folio *folio)             \
 { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }    \
 static __always_inline void __ClearPage##uname(struct page *page)   \
 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define TESTSETFLAG(uname, lname, policy)               \
 static __always_inline                          \
 bool folio_test_set_##lname(struct folio *folio)            \
 { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
 static __always_inline int TestSetPage##uname(struct page *page)    \
 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define TESTCLEARFLAG(uname, lname, policy)             \
 static __always_inline                          \
 bool folio_test_clear_##lname(struct folio *folio)          \
 { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
 static __always_inline int TestClearPage##uname(struct page *page)  \
 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define PAGEFLAG(uname, lname, policy)                  \
     TESTPAGEFLAG(uname, lname, policy)              \
     SETPAGEFLAG(uname, lname, policy)               \
     CLEARPAGEFLAG(uname, lname, policy)
 
 #define __PAGEFLAG(uname, lname, policy)                \
     TESTPAGEFLAG(uname, lname, policy)              \
     __SETPAGEFLAG(uname, lname, policy)             \
     __CLEARPAGEFLAG(uname, lname, policy)
 
 #define TESTSCFLAG(uname, lname, policy)                \
     TESTSETFLAG(uname, lname, policy)               \
     TESTCLEARFLAG(uname, lname, policy)
 
 #define TESTPAGEFLAG_FALSE(uname, lname)                \
 static inline bool folio_test_##lname(const struct folio *folio) { return false; } \
 static inline int Page##uname(const struct page *page) { return 0; }
 
 #define SETPAGEFLAG_NOOP(uname, lname)                  \
 static inline void folio_set_##lname(struct folio *folio) { }       \
 static inline void SetPage##uname(struct page *page) {  }
 
 #define CLEARPAGEFLAG_NOOP(uname, lname)                \
 static inline void folio_clear_##lname(struct folio *folio) { }     \
 static inline void ClearPage##uname(struct page *page) {  }
 
 #define __CLEARPAGEFLAG_NOOP(uname, lname)              \
 static inline void __folio_clear_##lname(struct folio *folio) { }   \
 static inline void __ClearPage##uname(struct page *page) {  }
 
 #define TESTSETFLAG_FALSE(uname, lname)                 \
 static inline bool folio_test_set_##lname(struct folio *folio)      \
 { return 0; }                               \
 static inline int TestSetPage##uname(struct page *page) { return 0; }
 
 #define TESTCLEARFLAG_FALSE(uname, lname)               \
 static inline bool folio_test_clear_##lname(struct folio *folio)    \
 { return 0; }                               \
 static inline int TestClearPage##uname(struct page *page) { return 0; }
 
 #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname)   \
     SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
 
 #define TESTSCFLAG_FALSE(uname, lname)                  \
     TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
 
 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
 PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
 PAGEFLAG(Referenced, referenced, PF_HEAD)
     TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
     __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
     __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
     TESTCLEARFLAG(LRU, lru, PF_HEAD)
 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
     TESTCLEARFLAG(Active, active, PF_HEAD)
 PAGEFLAG(Workingset, workingset, PF_HEAD)
     TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
 PAGEFLAG(Checked, checked, PF_NO_COMPOUND)     /* Used by some filesystems */
 
 /* Xen */
 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
     TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
     TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
 
 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
     __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
     __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
     __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
     __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
 
 /*
  * Private page markings that may be used by the filesystem that owns the page
  * for its own purposes.
  * - PG_private and PG_private_2 cause release_folio() and co to be invoked
  */
 PAGEFLAG(Private, private, PF_ANY)
 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
     TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
 
 /*
  * Only test-and-set exist for PG_writeback.  The unconditional operators are
  * risky: they bypass page accounting.
  */
 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
     TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
 
 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
     TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
 PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND)
     TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND)
 
 #ifdef CONFIG_HIGHMEM
 /*
  * Must use a macro here due to header dependency issues. page_zone() is not
  * available at this point.
  */
 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
 #else
 PAGEFLAG_FALSE(HighMem, highmem)
 #endif
 
 #ifdef CONFIG_SWAP
 static __always_inline bool folio_test_swapcache(struct folio *folio)
 {
     return folio_test_swapbacked(folio) &&
             test_bit(PG_swapcache, folio_flags(folio, 0));
 }
 
 static __always_inline bool PageSwapCache(struct page *page)
 {
     return folio_test_swapcache(page_folio(page));
 }
 
 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
 #else
 PAGEFLAG_FALSE(SwapCache, swapcache)
 #endif
 
 PAGEFLAG(Unevictable, unevictable, PF_HEAD)
     __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
     TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
 
 #ifdef CONFIG_MMU
 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
     __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
     TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
 #else
 PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked)
     TESTSCFLAG_FALSE(Mlocked, mlocked)
 #endif
 
 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
 #else
 PAGEFLAG_FALSE(Uncached, uncached)
 #endif
 
 #ifdef CONFIG_MEMORY_FAILURE
 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
 #define __PG_HWPOISON (1UL << PG_hwpoison)
 #define MAGIC_HWPOISON  0x48575053U /* HWPS */
 extern void SetPageHWPoisonTakenOff(struct page *page);
 extern void ClearPageHWPoisonTakenOff(struct page *page);
 extern bool take_page_off_buddy(struct page *page);
 extern bool put_page_back_buddy(struct page *page);
 #else
 PAGEFLAG_FALSE(HWPoison, hwpoison)
 #define __PG_HWPOISON 0
 #endif
 
 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
 TESTPAGEFLAG(Young, young, PF_ANY)
 SETPAGEFLAG(Young, young, PF_ANY)
 TESTCLEARFLAG(Young, young, PF_ANY)
 PAGEFLAG(Idle, idle, PF_ANY)
 #endif
 
 #ifdef CONFIG_KASAN_HW_TAGS
 PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD)
 #else
 PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison)
 #endif
 
 /*
  * PageReported() is used to track reported free pages within the Buddy
  * allocator. We can use the non-atomic version of the test and set
  * operations as both should be shielded with the zone lock to prevent
  * any possible races on the setting or clearing of the bit.
  */
 __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY)
 #else
 PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
 #endif
 
 /*
  * On an anonymous page mapped into a user virtual memory area,
  * page->mapping points to its anon_vma, not to a struct address_space;
  * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
  *
  * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
  * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
  * bit; and then page->mapping points, not to an anon_vma, but to a private
  * structure which KSM associates with that merged page.  See ksm.h.
  *
  * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
  * page and then page->mapping points to a struct movable_operations.
  *
  * Please note that, confusingly, "page_mapping" refers to the inode
  * address_space which maps the page from disk; whereas "page_mapped"
  * refers to user virtual address space into which the page is mapped.
  */
 #define PAGE_MAPPING_ANON   0x1
 #define PAGE_MAPPING_MOVABLE    0x2
 #define PAGE_MAPPING_KSM    (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
 #define PAGE_MAPPING_FLAGS  (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
 
 /*
  * Different with flags above, this flag is used only for fsdax mode.  It
  * indicates that this page->mapping is now under reflink case.
  */
 #define PAGE_MAPPING_DAX_COW    0x1
 
 static __always_inline bool folio_mapping_flags(struct folio *folio)
 {
     return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0;
 }
 
 static __always_inline int PageMappingFlags(struct page *page)
 {
     return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
 }
 
 static __always_inline bool folio_test_anon(struct folio *folio)
 {
     return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
 }
 
 static __always_inline bool PageAnon(struct page *page)
 {
     return folio_test_anon(page_folio(page));
 }
 
 static __always_inline bool __folio_test_movable(const struct folio *folio)
 {
     return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
             PAGE_MAPPING_MOVABLE;
 }
 
 static __always_inline int __PageMovable(struct page *page)
 {
     return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
                 PAGE_MAPPING_MOVABLE;
 }
 
 #ifdef CONFIG_KSM
 /*
  * A KSM page is one of those write-protected "shared pages" or "merged pages"
  * which KSM maps into multiple mms, wherever identical anonymous page content
  * is found in VM_MERGEABLE vmas.  It's a PageAnon page, pointing not to any
  * anon_vma, but to that page's node of the stable tree.
  */
 static __always_inline bool folio_test_ksm(struct folio *folio)
 {
     return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
                 PAGE_MAPPING_KSM;
 }
 
 static __always_inline bool PageKsm(struct page *page)
 {
     return folio_test_ksm(page_folio(page));
 }
 #else
 TESTPAGEFLAG_FALSE(Ksm, ksm)
 #endif
 
 u64 stable_page_flags(struct page *page);
 
 /**
  * folio_test_uptodate - Is this folio up to date?
  * @folio: The folio.
  *
  * The uptodate flag is set on a folio when every byte in the folio is
  * at least as new as the corresponding bytes on storage.  Anonymous
  * and CoW folios are always uptodate.  If the folio is not uptodate,
  * some of the bytes in it may be; see the is_partially_uptodate()
  * address_space operation.
  */
 static inline bool folio_test_uptodate(struct folio *folio)
 {
     bool ret = test_bit(PG_uptodate, folio_flags(folio, 0));
     /*
      * Must ensure that the data we read out of the folio is loaded
      * _after_ we've loaded folio->flags to check the uptodate bit.
      * We can skip the barrier if the folio is not uptodate, because
      * we wouldn't be reading anything from it.
      *
      * See folio_mark_uptodate() for the other side of the story.
      */
     if (ret)
         smp_rmb();
 
     return ret;
 }
 
 static inline int PageUptodate(struct page *page)
 {
     return folio_test_uptodate(page_folio(page));
 }
 
 static __always_inline void __folio_mark_uptodate(struct folio *folio)
 {
     smp_wmb();
     __set_bit(PG_uptodate, folio_flags(folio, 0));
 }
 
 static __always_inline void folio_mark_uptodate(struct folio *folio)
 {
     /*
      * Memory barrier must be issued before setting the PG_uptodate bit,
      * so that all previous stores issued in order to bring the folio
      * uptodate are actually visible before folio_test_uptodate becomes true.
      */
     smp_wmb();
     set_bit(PG_uptodate, folio_flags(folio, 0));
 }
 
 static __always_inline void __SetPageUptodate(struct page *page)
 {
     __folio_mark_uptodate((struct folio *)page);
 }
 
 static __always_inline void SetPageUptodate(struct page *page)
 {
     folio_mark_uptodate((struct folio *)page);
 }
 
 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
 
 bool __folio_start_writeback(struct folio *folio, bool keep_write);
 bool set_page_writeback(struct page *page);
 
 #define folio_start_writeback(folio)            \
     __folio_start_writeback(folio, false)
 #define folio_start_writeback_keepwrite(folio)  \
     __folio_start_writeback(folio, true)
 
 static inline void set_page_writeback_keepwrite(struct page *page)
 {
     folio_start_writeback_keepwrite(page_folio(page));
 }
 
 static inline bool test_set_page_writeback(struct page *page)
 {
     return set_page_writeback(page);
 }
 
 static __always_inline bool folio_test_head(struct folio *folio)
 {
     return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY));
 }
 
 static __always_inline int PageHead(struct page *page)
 {
     PF_POISONED_CHECK(page);
     return test_bit(PG_head, &page->flags) && !page_is_fake_head(page);
 }
 
 __SETPAGEFLAG(Head, head, PF_ANY)
 __CLEARPAGEFLAG(Head, head, PF_ANY)
 CLEARPAGEFLAG(Head, head, PF_ANY)
 
 /**
  * folio_test_large() - Does this folio contain more than one page?
  * @folio: The folio to test.
  *
  * Return: True if the folio is larger than one page.
  */
 static inline bool folio_test_large(struct folio *folio)
 {
     return folio_test_head(folio);
 }
 
 static __always_inline void set_compound_head(struct page *page, struct page *head)
 {
     WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
 }
 
 static __always_inline void clear_compound_head(struct page *page)
 {
     WRITE_ONCE(page->compound_head, 0);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline void ClearPageCompound(struct page *page)
 {
     BUG_ON(!PageHead(page));
     ClearPageHead(page);
 }
 #endif
 
 #define PG_head_mask ((1UL << PG_head))
 
 #ifdef CONFIG_HUGETLB_PAGE
 int PageHuge(struct page *page);
 int PageHeadHuge(struct page *page);
 static inline bool folio_test_hugetlb(struct folio *folio)
 {
     return PageHeadHuge(&folio->page);
 }
 #else
 TESTPAGEFLAG_FALSE(Huge, hugetlb)
 TESTPAGEFLAG_FALSE(HeadHuge, headhuge)
 #endif
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /*
  * PageHuge() only returns true for hugetlbfs pages, but not for
  * normal or transparent huge pages.
  *
  * PageTransHuge() returns true for both transparent huge and
  * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
  * called only in the core VM paths where hugetlbfs pages can't exist.
  */
 static inline int PageTransHuge(struct page *page)
 {
     VM_BUG_ON_PAGE(PageTail(page), page);
     return PageHead(page);
 }
 
 static inline bool folio_test_transhuge(struct folio *folio)
 {
     return folio_test_head(folio);
 }
 
 /*
  * PageTransCompound returns true for both transparent huge pages
  * and hugetlbfs pages, so it should only be called when it's known
  * that hugetlbfs pages aren't involved.
  */
 static inline int PageTransCompound(struct page *page)
 {
     return PageCompound(page);
 }
 
 /*
  * PageTransTail returns true for both transparent huge pages
  * and hugetlbfs pages, so it should only be called when it's known
  * that hugetlbfs pages aren't involved.
  */
 static inline int PageTransTail(struct page *page)
 {
     return PageTail(page);
 }
 
 /*
  * PageDoubleMap indicates that the compound page is mapped with PTEs as well
  * as PMDs.
  *
  * This is required for optimization of rmap operations for THP: we can postpone
  * per small page mapcount accounting (and its overhead from atomic operations)
  * until the first PMD split.
  *
  * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
  * by one. This reference will go away with last compound_mapcount.
  *
  * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
  */
 PAGEFLAG(DoubleMap, double_map, PF_SECOND)
     TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
 #else
 TESTPAGEFLAG_FALSE(TransHuge, transhuge)
 TESTPAGEFLAG_FALSE(TransCompound, transcompound)
 TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
 TESTPAGEFLAG_FALSE(TransTail, transtail)
 PAGEFLAG_FALSE(DoubleMap, double_map)
     TESTSCFLAG_FALSE(DoubleMap, double_map)
 #endif
 
 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 /*
  * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
  * compound page.
  *
  * This flag is set by hwpoison handler.  Cleared by THP split or free page.
  */
 PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
     TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
 #else
 PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
     TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
 #endif
 
 /*
  * Check if a page is currently marked HWPoisoned. Note that this check is
  * best effort only and inherently racy: there is no way to synchronize with
  * failing hardware.
  */
 static inline bool is_page_hwpoison(struct page *page)
 {
     if (PageHWPoison(page))
         return true;
     return PageHuge(page) && PageHWPoison(compound_head(page));
 }
 
 /*
  * For pages that are never mapped to userspace (and aren't PageSlab),
  * page_type may be used.  Because it is initialised to -1, we invert the
  * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
  * __ClearPageFoo *sets* the bit used for PageFoo.  We reserve a few high and
  * low bits so that an underflow or overflow of page_mapcount() won't be
  * mistaken for a page type value.
  */
 
 #define PAGE_TYPE_BASE  0xf0000000
 /* Reserve      0x0000007f to catch underflows of page_mapcount */
 #define PAGE_MAPCOUNT_RESERVE   -128
 #define PG_buddy    0x00000080
 #define PG_offline  0x00000100
 #define PG_table    0x00000200
 #define PG_guard    0x00000400
 
 #define PageType(page, flag)                        \
     ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
 
 static inline int page_has_type(struct page *page)
 {
     return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
 }
 
 #define PAGE_TYPE_OPS(uname, lname)                 \
 static __always_inline int Page##uname(struct page *page)       \
 {                                   \
     return PageType(page, PG_##lname);              \
 }                                   \
 static __always_inline void __SetPage##uname(struct page *page)     \
 {                                   \
     VM_BUG_ON_PAGE(!PageType(page, 0), page);           \
     page->page_type &= ~PG_##lname;                 \
 }                                   \
 static __always_inline void __ClearPage##uname(struct page *page)   \
 {                                   \
     VM_BUG_ON_PAGE(!Page##uname(page), page);           \
     page->page_type |= PG_##lname;                  \
 }
 
 /*
  * PageBuddy() indicates that the page is free and in the buddy system
  * (see mm/page_alloc.c).
  */
 PAGE_TYPE_OPS(Buddy, buddy)
 
 /*
  * PageOffline() indicates that the page is logically offline although the
  * containing section is online. (e.g. inflated in a balloon driver or
  * not onlined when onlining the section).
  * The content of these pages is effectively stale. Such pages should not
  * be touched (read/write/dump/save) except by their owner.
  *
  * If a driver wants to allow to offline unmovable PageOffline() pages without
  * putting them back to the buddy, it can do so via the memory notifier by
  * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
  * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
  * pages (now with a reference count of zero) are treated like free pages,
  * allowing the containing memory block to get offlined. A driver that
  * relies on this feature is aware that re-onlining the memory block will
  * require to re-set the pages PageOffline() and not giving them to the
  * buddy via online_page_callback_t.
  *
  * There are drivers that mark a page PageOffline() and expect there won't be
  * any further access to page content. PFN walkers that read content of random
  * pages should check PageOffline() and synchronize with such drivers using
  * page_offline_freeze()/page_offline_thaw().
  */
 PAGE_TYPE_OPS(Offline, offline)
 
 extern void page_offline_freeze(void);
 extern void page_offline_thaw(void);
 extern void page_offline_begin(void);
 extern void page_offline_end(void);
 
 /*
  * Marks pages in use as page tables.
  */
 PAGE_TYPE_OPS(Table, table)
 
 /*
  * Marks guardpages used with debug_pagealloc.
  */
 PAGE_TYPE_OPS(Guard, guard)
 
 extern bool is_free_buddy_page(struct page *page);
 
 PAGEFLAG(Isolated, isolated, PF_ANY);
 
 static __always_inline int PageAnonExclusive(struct page *page)
 {
     VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
     VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
     return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
 }
 
 static __always_inline void SetPageAnonExclusive(struct page *page)
 {
     VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
     VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
     set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
 }
 
 static __always_inline void ClearPageAnonExclusive(struct page *page)
 {
     VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
     VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
     clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
 }
 
 static __always_inline void __ClearPageAnonExclusive(struct page *page)
 {
     VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
     VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
     __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
 }
 
 #ifdef CONFIG_MMU
 #define __PG_MLOCKED        (1UL << PG_mlocked)
 #else
 #define __PG_MLOCKED        0
 #endif
 
 /*
  * Flags checked when a page is freed.  Pages being freed should not have
  * these flags set.  If they are, there is a problem.
  */
 #define PAGE_FLAGS_CHECK_AT_FREE                \
     (1UL << PG_lru      | 1UL << PG_locked  |   \
      1UL << PG_private  | 1UL << PG_private_2   |   \
      1UL << PG_writeback    | 1UL << PG_reserved    |   \
      1UL << PG_slab     | 1UL << PG_active  |   \
      1UL << PG_unevictable  | __PG_MLOCKED)
 
 /*
  * Flags checked when a page is prepped for return by the page allocator.
  * Pages being prepped should not have these flags set.  If they are set,
  * there has been a kernel bug or struct page corruption.
  *
  * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
  * alloc-free cycle to prevent from reusing the page.
  */
 #define PAGE_FLAGS_CHECK_AT_PREP    \
     (PAGEFLAGS_MASK & ~__PG_HWPOISON)
 
 #define PAGE_FLAGS_PRIVATE              \
     (1UL << PG_private | 1UL << PG_private_2)
 /**
  * page_has_private - Determine if page has private stuff
  * @page: The page to be checked
  *
  * Determine if a page has private stuff, indicating that release routines
  * should be invoked upon it.
  */
 static inline int page_has_private(struct page *page)
 {
     return !!(page->flags & PAGE_FLAGS_PRIVATE);
 }
 
 static inline bool folio_has_private(struct folio *folio)
 {
     return page_has_private(&folio->page);
 }
 
 #undef PF_ANY
 #undef PF_HEAD
 #undef PF_ONLY_HEAD
 #undef PF_NO_TAIL
 #undef PF_NO_COMPOUND
 #undef PF_SECOND
 #endif /* !__GENERATING_BOUNDS_H */
 
 #endif  /* PAGE_FLAGS_H */

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