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-rw-r--r--include/linux/page-flags.h33
1 files changed, 25 insertions, 8 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 74e4dda91238..6b5818d6de32 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -79,6 +79,7 @@ enum pageflags {
PG_dirty,
PG_lru,
PG_active,
+ PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
PG_slab,
PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
PG_arch_1,
@@ -87,7 +88,6 @@ enum pageflags {
PG_private_2, /* If pagecache, has fs aux data */
PG_writeback, /* Page is under writeback */
PG_head, /* A head page */
- PG_swapcache, /* Swap page: swp_entry_t in private */
PG_mappedtodisk, /* Has blocks allocated on-disk */
PG_reclaim, /* To be reclaimed asap */
PG_swapbacked, /* Page is backed by RAM/swap */
@@ -110,6 +110,9 @@ enum pageflags {
/* 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.
@@ -167,6 +170,9 @@ static __always_inline int PageCompound(struct page *page)
* 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.
@@ -176,6 +182,9 @@ static __always_inline int PageCompound(struct page *page)
*/
#define PF_ANY(page, enforce) page
#define PF_HEAD(page, enforce) compound_head(page)
+#define PF_ONLY_HEAD(page, enforce) ({ \
+ VM_BUG_ON_PGFLAGS(PageTail(page), page); \
+ page;})
#define PF_NO_TAIL(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
compound_head(page);})
@@ -253,6 +262,7 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
+PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
PAGEFLAG(Referenced, referenced, PF_HEAD)
TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
@@ -314,7 +324,13 @@ PAGEFLAG_FALSE(HighMem)
#endif
#ifdef CONFIG_SWAP
-PAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND)
+static __always_inline int PageSwapCache(struct page *page)
+{
+ return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
+
+}
+SETPAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND)
+CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND)
#else
PAGEFLAG_FALSE(SwapCache)
#endif
@@ -701,12 +717,12 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
* Flags checked when a page is freed. Pages being freed should not have
* these flags set. It 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_swapcache | 1UL << PG_active | \
- 1UL << PG_unevictable | __PG_MLOCKED)
+#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.
@@ -735,6 +751,7 @@ static inline int page_has_private(struct page *page)
#undef PF_ANY
#undef PF_HEAD
+#undef PF_ONLY_HEAD
#undef PF_NO_TAIL
#undef PF_NO_COMPOUND
#endif /* !__GENERATING_BOUNDS_H */
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