Merge "page-flags: define PG_locked behavior on compound pages"

3 files changed, 139 insertions, 103 deletions

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 772362adf471..053824b0a412 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -56,4 +56,10 @@ void dump_mm(const struct mm_struct *mm);
 #define VIRTUAL_BUG_ON(cond) do { } while (0)
 #endif
 
+#ifdef CONFIG_DEBUG_VM_PGFLAGS
+#define VM_BUG_ON_PGFLAGS(cond, page) VM_BUG_ON_PAGE(cond, page)
+#else
+#define VM_BUG_ON_PGFLAGS(cond, page) BUILD_BUG_ON_INVALID(cond)
+#endif
+
 #endif
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 86c233be1cfc..985fb2c63cb7 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -139,49 +139,101 @@ enum pageflags {
 
 #ifndef __GENERATING_BOUNDS_H
 
+struct page;	/* forward declaration */
+
+static inline struct page *compound_head(struct page *page)
+{
+	unsigned long head = READ_ONCE(page->compound_head);
+
+	if (unlikely(head & 1))
+		return (struct page *) (head - 1);
+	return page;
+}
+
+static inline int PageTail(struct page *page)
+{
+	return READ_ONCE(page->compound_head) & 1;
+}
+
+static inline int PageCompound(struct page *page)
+{
+	return test_bit(PG_head, &page->flags) || PageTail(page);
+}
+
+/*
+ * Page flags policies wrt compound pages
+ *
+ * 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_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.
+ */
+#define PF_ANY(page, enforce)	page
+#define PF_HEAD(page, enforce)	compound_head(page)
+#define PF_NO_TAIL(page, enforce) ({					\
+		VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page);	\
+		compound_head(page);})
+#define PF_NO_COMPOUND(page, enforce) ({					\
+		VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page);	\
+		page;})
+
 /*
  * Macros to create function definitions for page flags
  */
-#define TESTPAGEFLAG(uname, lname)					\
-static inline int Page##uname(const struct page *page)			\
-			{ return test_bit(PG_##lname, &page->flags); }
+#define TESTPAGEFLAG(uname, lname, policy)				\
+static inline int Page##uname(struct page *page)			\
+	{ return test_bit(PG_##lname, &policy(page, 0)->flags); }
 
-#define SETPAGEFLAG(uname, lname)					\
+#define SETPAGEFLAG(uname, lname, policy)				\
 static inline void SetPage##uname(struct page *page)			\
-			{ set_bit(PG_##lname, &page->flags); }
+	{ set_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define CLEARPAGEFLAG(uname, lname)					\
+#define CLEARPAGEFLAG(uname, lname, policy)				\
 static inline void ClearPage##uname(struct page *page)			\
-			{ clear_bit(PG_##lname, &page->flags); }
+	{ clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define __SETPAGEFLAG(uname, lname)					\
+#define __SETPAGEFLAG(uname, lname, policy)				\
 static inline void __SetPage##uname(struct page *page)			\
-			{ __set_bit(PG_##lname, &page->flags); }
+	{ __set_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define __CLEARPAGEFLAG(uname, lname)					\
+#define __CLEARPAGEFLAG(uname, lname, policy)				\
 static inline void __ClearPage##uname(struct page *page)		\
-			{ __clear_bit(PG_##lname, &page->flags); }
+	{ __clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define TESTSETFLAG(uname, lname)					\
+#define TESTSETFLAG(uname, lname, policy)				\
 static inline int TestSetPage##uname(struct page *page)			\
-		{ return test_and_set_bit(PG_##lname, &page->flags); }
+	{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define TESTCLEARFLAG(uname, lname)					\
+#define TESTCLEARFLAG(uname, lname, policy)				\
 static inline int TestClearPage##uname(struct page *page)		\
-		{ return test_and_clear_bit(PG_##lname, &page->flags); }
+	{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define __TESTCLEARFLAG(uname, lname)					\
+#define __TESTCLEARFLAG(uname, lname, policy)				\
 static inline int __TestClearPage##uname(struct page *page)		\
-		{ return __test_and_clear_bit(PG_##lname, &page->flags); }
+	{ return __test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
-#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
-	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
+#define PAGEFLAG(uname, lname, policy)					\
+	TESTPAGEFLAG(uname, lname, policy)				\
+	SETPAGEFLAG(uname, lname, policy)				\
+	CLEARPAGEFLAG(uname, lname, policy)
 
-#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
-	__SETPAGEFLAG(uname, lname)  __CLEARPAGEFLAG(uname, lname)
+#define __PAGEFLAG(uname, lname, policy)				\
+	TESTPAGEFLAG(uname, lname, policy)				\
+	__SETPAGEFLAG(uname, lname, policy)				\
+	__CLEARPAGEFLAG(uname, lname, policy)
 
-#define TESTSCFLAG(uname, lname)					\
-	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
+#define TESTSCFLAG(uname, lname, policy)				\
+	TESTSETFLAG(uname, lname, policy)				\
+	TESTCLEARFLAG(uname, lname, policy)
 
 #define TESTPAGEFLAG_FALSE(uname)					\
 static inline int Page##uname(const struct page *page) { return 0; }
@@ -210,28 +262,28 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 #define TESTSCFLAG_FALSE(uname)						\
 	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 
-struct page;	/* forward declaration */
-
-TESTPAGEFLAG(Locked, locked)
-PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
-PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
-	__SETPAGEFLAG(Referenced, referenced)
-PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
-PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
-PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
-	TESTCLEARFLAG(Active, active)
-__PAGEFLAG(Slab, slab)
-PAGEFLAG(Checked, checked)		/* Used by some filesystems */
-PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned)	/* Xen */
-PAGEFLAG(SavePinned, savepinned);			/* Xen */
-PAGEFLAG(Foreign, foreign);				/* Xen */
-PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
-PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
-	__SETPAGEFLAG(SwapBacked, swapbacked)
-
-__PAGEFLAG(SlobFree, slob_free)
+__PAGEFLAG(Locked, locked, PF_NO_TAIL)
+PAGEFLAG(Error, error, PF_ANY) TESTCLEARFLAG(Error, error, PF_ANY)
+PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY)
+	__SETPAGEFLAG(Referenced, referenced, PF_ANY)
+PAGEFLAG(Dirty, dirty, PF_ANY) TESTSCFLAG(Dirty, dirty, PF_ANY)
+	__CLEARPAGEFLAG(Dirty, dirty, PF_ANY)
+PAGEFLAG(LRU, lru, PF_ANY) __CLEARPAGEFLAG(LRU, lru, PF_ANY)
+PAGEFLAG(Active, active, PF_ANY) __CLEARPAGEFLAG(Active, active, PF_ANY)
+	TESTCLEARFLAG(Active, active, PF_ANY)
+__PAGEFLAG(Slab, slab, PF_ANY)
+PAGEFLAG(Checked, checked, PF_ANY)		/* Used by some filesystems */
+PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)	/* Xen */
+PAGEFLAG(SavePinned, savepinned, PF_ANY);			/* Xen */
+PAGEFLAG(Foreign, foreign, PF_ANY);				/* Xen */
+PAGEFLAG(Reserved, reserved, PF_ANY) __CLEARPAGEFLAG(Reserved, reserved, PF_ANY)
+PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
+	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
+	__SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
+
+__PAGEFLAG(SlobFree, slob_free, PF_ANY)
 #ifdef CONFIG_ZCACHE
-PAGEFLAG(WasActive, was_active)
+PAGEFLAG(WasActive, was_active, PF_ANY)
 #else
 PAGEFLAG_FALSE(WasActive)
 #endif
@@ -241,21 +293,22 @@ PAGEFLAG_FALSE(WasActive)
  * for its own purposes.
  * - PG_private and PG_private_2 cause releasepage() and co to be invoked
  */
-PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
-	__CLEARPAGEFLAG(Private, private)
-PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
-PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
+PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
+	__CLEARPAGEFLAG(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) TESTSCFLAG(Writeback, writeback)
-PAGEFLAG(MappedToDisk, mappedtodisk)
+TESTPAGEFLAG(Writeback, writeback, PF_ANY) TESTSCFLAG(Writeback, writeback, PF_ANY)
+PAGEFLAG(MappedToDisk, mappedtodisk, PF_ANY)
 
 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
-PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
-PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim)
+PAGEFLAG(Reclaim, reclaim, PF_ANY) TESTCLEARFLAG(Reclaim, reclaim, PF_ANY)
+PAGEFLAG(Readahead, reclaim, PF_ANY) TESTCLEARFLAG(Readahead, reclaim, PF_ANY)
 
 #ifdef CONFIG_HIGHMEM
 /*
@@ -268,31 +321,32 @@ PAGEFLAG_FALSE(HighMem)
 #endif
 
 #ifdef CONFIG_SWAP
-PAGEFLAG(SwapCache, swapcache)
+PAGEFLAG(SwapCache, swapcache, PF_ANY)
 #else
 PAGEFLAG_FALSE(SwapCache)
 #endif
 
-PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
-	TESTCLEARFLAG(Unevictable, unevictable)
+PAGEFLAG(Unevictable, unevictable, PF_ANY)
+	__CLEARPAGEFLAG(Unevictable, unevictable, PF_ANY)
+	TESTCLEARFLAG(Unevictable, unevictable, PF_ANY)
 
 #ifdef CONFIG_MMU
-PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
-	TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
+PAGEFLAG(Mlocked, mlocked, PF_ANY) __CLEARPAGEFLAG(Mlocked, mlocked, PF_ANY)
+	TESTSCFLAG(Mlocked, mlocked, PF_ANY) __TESTCLEARFLAG(Mlocked, mlocked, PF_ANY)
 #else
 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
 	TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
 #endif
 
 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
-PAGEFLAG(Uncached, uncached)
+PAGEFLAG(Uncached, uncached, PF_ANY)
 #else
 PAGEFLAG_FALSE(Uncached)
 #endif
 
 #ifdef CONFIG_MEMORY_FAILURE
-PAGEFLAG(HWPoison, hwpoison)
-TESTSCFLAG(HWPoison, hwpoison)
+PAGEFLAG(HWPoison, hwpoison, PF_ANY)
+TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
 #define __PG_HWPOISON (1UL << PG_hwpoison)
 #else
 PAGEFLAG_FALSE(HWPoison)
@@ -300,10 +354,10 @@ PAGEFLAG_FALSE(HWPoison)
 #endif
 
 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
-TESTPAGEFLAG(Young, young)
-SETPAGEFLAG(Young, young)
-TESTCLEARFLAG(Young, young)
-PAGEFLAG(Idle, idle)
+TESTPAGEFLAG(Young, young, PF_ANY)
+SETPAGEFLAG(Young, young, PF_ANY)
+TESTCLEARFLAG(Young, young, PF_ANY)
+PAGEFLAG(Idle, idle, PF_ANY)
 #endif
 
 /*
@@ -397,7 +451,7 @@ static inline void SetPageUptodate(struct page *page)
 	set_bit(PG_uptodate, &(page)->flags);
 }
 
-CLEARPAGEFLAG(Uptodate, uptodate)
+CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY)
 
 int test_clear_page_writeback(struct page *page);
 int __test_set_page_writeback(struct page *page, bool keep_write);
@@ -417,12 +471,7 @@ static inline void set_page_writeback_keepwrite(struct page *page)
 	test_set_page_writeback_keepwrite(page);
 }
 
-__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
-
-static inline int PageTail(struct page *page)
-{
-	return READ_ONCE(page->compound_head) & 1;
-}
+__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
 
 static inline void set_compound_head(struct page *page, struct page *head)
 {
@@ -434,20 +483,6 @@ static inline void clear_compound_head(struct page *page)
 	WRITE_ONCE(page->compound_head, 0);
 }
 
-static inline struct page *compound_head(struct page *page)
-{
-	unsigned long head = READ_ONCE(page->compound_head);
-
-	if (unlikely(head & 1))
-		return (struct page *) (head - 1);
-	return page;
-}
-
-static inline int PageCompound(struct page *page)
-{
-	return PageHead(page) || PageTail(page);
-
-}
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline void ClearPageCompound(struct page *page)
 {
@@ -573,7 +608,7 @@ static inline void __ClearPageBalloon(struct page *page)
 	atomic_set(&page->_mapcount, -1);
 }
 
-__PAGEFLAG(Isolated, isolated);
+__PAGEFLAG(Isolated, isolated, PF_ANY);
 
 /*
  * If network-based swap is enabled, sl*b must keep track of whether pages
@@ -652,6 +687,10 @@ static inline int page_has_private(struct page *page)
 	return !!(page->flags & PAGE_FLAGS_PRIVATE);
 }
 
+#undef PF_ANY
+#undef PF_HEAD
+#undef PF_NO_TAIL
+#undef PF_NO_COMPOUND
 #endif /* !__GENERATING_BOUNDS_H */
 
 #endif	/* PAGE_FLAGS_H */
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 443a063e6af8..d2f4a732b3e8 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -441,18 +441,9 @@ extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
 				unsigned int flags);
 extern void unlock_page(struct page *page);
 
-static inline void __set_page_locked(struct page *page)
-{
-	__set_bit(PG_locked, &page->flags);
-}
-
-static inline void __clear_page_locked(struct page *page)
-{
-	__clear_bit(PG_locked, &page->flags);
-}
-
 static inline int trylock_page(struct page *page)
 {
+	page = compound_head(page);
 	return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
 }
 
@@ -505,9 +496,9 @@ extern int wait_on_page_bit_killable_timeout(struct page *page,
 
 static inline int wait_on_page_locked_killable(struct page *page)
 {
-	if (PageLocked(page))
-		return wait_on_page_bit_killable(page, PG_locked);
-	return 0;
+	if (!PageLocked(page))
+		return 0;
+	return wait_on_page_bit_killable(compound_head(page), PG_locked);
 }
 
 extern wait_queue_head_t *page_waitqueue(struct page *page);
@@ -526,7 +517,7 @@ static inline void wake_up_page(struct page *page, int bit)
 static inline void wait_on_page_locked(struct page *page)
 {
 	if (PageLocked(page))
-		wait_on_page_bit(page, PG_locked);
+		wait_on_page_bit(compound_head(page), PG_locked);
 }
 
 /* 
@@ -672,17 +663,17 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
 
 /*
  * Like add_to_page_cache_locked, but used to add newly allocated pages:
- * the page is new, so we can just run __set_page_locked() against it.
+ * the page is new, so we can just run __SetPageLocked() against it.
  */
 static inline int add_to_page_cache(struct page *page,
 		struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask)
 {
 	int error;
 
-	__set_page_locked(page);
+	__SetPageLocked(page);
 	error = add_to_page_cache_locked(page, mapping, offset, gfp_mask);
 	if (unlikely(error))
-		__clear_page_locked(page);
+		__ClearPageLocked(page);
 	return error;
 }