/* SPDX-License-Identifier: GPL-2.0 */
/* Linux v6.1, commit 830b3c68c1fb1e9176028d02ef86f3cf76aa2476.
 * Source: include/linux/page-flags.h
 * Whole helper definitions and complete configuration groups.
 * Kernel context; not a standalone translation unit.
 */

/* Upstream lines 300-313. */

#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


/* Upstream lines 780-804. */
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);
}


/* Upstream lines 825-914. */

#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


/* Upstream lines 969-1016. */
/*
 * 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);


/* Upstream lines 1018-1045. */
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);
}