[linux-2.6-block.git] / include / linux / page-flags.h

/*
 * Macros for manipulating and testing page->flags
 */

#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H

#include <linux/types.h>
#ifndef __GENERATING_BOUNDS_H
#include <linux/mm_types.h>
#include <linux/bounds.h>
#endif /* !__GENERATING_BOUNDS_H */

/*
 * Various page->flags bits:
 *
 * PG_reserved is set for special pages, which can never be swapped out. Some
 * of them might not even exist (eg empty_bad_page)...
 *
 * 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_uptodate tells whether the page's contents is valid.  When a read
 * completes, the page becomes uptodate, unless a disk I/O error happened.
 *
 * 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_highmem pages are not permanently mapped into the kernel virtual address
 * space, they need to be kmapped separately for doing IO on the pages.  The
 * struct page (these bits with information) are always mapped into kernel
 * address space...
 *
 * PG_buddy is set to indicate that the page is free and in the buddy system
 * (see mm/page_alloc.c).
 *
 * 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 *_dontuse flags.  Use the macros.  Otherwise you'll break
 * locked- and dirty-page accounting.
 *
 * 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_error,
	PG_referenced,
	PG_uptodate,
	PG_dirty,
	PG_lru,
	PG_active,
	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 */
#ifdef CONFIG_PAGEFLAGS_EXTENDED
	PG_head,		/* A head page */
	PG_tail,		/* A tail page */
#else
	PG_compound,		/* A compound page */
#endif
	PG_swapcache,		/* Swap page: swp_entry_t in private */
	PG_mappedtodisk,	/* Has blocks allocated on-disk */
	PG_reclaim,		/* To be reclaimed asap */
	PG_buddy,		/* Page is free, on buddy lists */
	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
	__NR_PAGEFLAGS,

	/* Filesystems */
	PG_checked = PG_owner_priv_1,

	/* 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 */
	PG_pinned = PG_owner_priv_1,
	PG_savepinned = PG_dirty,

	/* SLOB */
	PG_slob_free = PG_private,

	/* SLUB */
	PG_slub_frozen = PG_active,
	PG_slub_debug = PG_error,
};

#ifndef __GENERATING_BOUNDS_H

/*
 * Macros to create function definitions for page flags
 */
#define TESTPAGEFLAG(uname, lname)					\
static inline int Page##uname(struct page *page) 			\
			{ return test_bit(PG_##lname, &page->flags); }

#define SETPAGEFLAG(uname, lname)					\
static inline void SetPage##uname(struct page *page)			\
			{ set_bit(PG_##lname, &page->flags); }

#define CLEARPAGEFLAG(uname, lname)					\
static inline void ClearPage##uname(struct page *page)			\
			{ clear_bit(PG_##lname, &page->flags); }

#define __SETPAGEFLAG(uname, lname)					\
static inline void __SetPage##uname(struct page *page)			\
			{ __set_bit(PG_##lname, &page->flags); }

#define __CLEARPAGEFLAG(uname, lname)					\
static inline void __ClearPage##uname(struct page *page)		\
			{ __clear_bit(PG_##lname, &page->flags); }

#define TESTSETFLAG(uname, lname)					\
static inline int TestSetPage##uname(struct page *page)			\
		{ return test_and_set_bit(PG_##lname, &page->flags); }

#define TESTCLEARFLAG(uname, lname)					\
static inline int TestClearPage##uname(struct page *page)		\
		{ return test_and_clear_bit(PG_##lname, &page->flags); }

#define __TESTCLEARFLAG(uname, lname)					\
static inline int __TestClearPage##uname(struct page *page)		\
		{ return __test_and_clear_bit(PG_##lname, &page->flags); }

#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)

#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
	__SETPAGEFLAG(uname, lname)  __CLEARPAGEFLAG(uname, lname)

#define PAGEFLAG_FALSE(uname) 						\
static inline int Page##uname(struct page *page) 			\
			{ return 0; }

#define TESTSCFLAG(uname, lname)					\
	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)

#define SETPAGEFLAG_NOOP(uname)						\
static inline void SetPage##uname(struct page *page) {  }

#define CLEARPAGEFLAG_NOOP(uname)					\
static inline void ClearPage##uname(struct page *page) {  }

#define __CLEARPAGEFLAG_NOOP(uname)					\
static inline void __ClearPage##uname(struct page *page) {  }

#define TESTCLEARFLAG_FALSE(uname)					\
static inline int TestClearPage##uname(struct page *page) { return 0; }

#define __TESTCLEARFLAG_FALSE(uname)					\
static inline int __TestClearPage##uname(struct page *page) { return 0; }

struct page;	/* forward declaration */

TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
PAGEFLAG(Error, error)
PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(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(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)

__PAGEFLAG(SlobFree, slob_free)

__PAGEFLAG(SlubFrozen, slub_frozen)
__PAGEFLAG(SlubDebug, slub_debug)

/*
 * 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 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)

/*
 * Only test-and-set exist for PG_writeback.  The unconditional operators are
 * risky: they bypass page accounting.
 */
TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
__PAGEFLAG(Buddy, buddy)
PAGEFLAG(MappedToDisk, mappedtodisk)

/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
PAGEFLAG(Readahead, reclaim)		/* Reminder to do async read-ahead */

#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(page_zone(__p))
#else
PAGEFLAG_FALSE(HighMem)
#endif

#ifdef CONFIG_SWAP
PAGEFLAG(SwapCache, swapcache)
#else
PAGEFLAG_FALSE(SwapCache)
	SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
#endif

PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
	TESTCLEARFLAG(Unevictable, unevictable)

#ifdef CONFIG_MMU
PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
	TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
#else
PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked)
	TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
#endif

#ifdef CONFIG_ARCH_USES_PG_UNCACHED
PAGEFLAG(Uncached, uncached)
#else
PAGEFLAG_FALSE(Uncached)
#endif

#ifdef CONFIG_MEMORY_FAILURE
PAGEFLAG(HWPoison, hwpoison)
TESTSETFLAG(HWPoison, hwpoison)
#define __PG_HWPOISON (1UL << PG_hwpoison)
#else
PAGEFLAG_FALSE(HWPoison)
#define __PG_HWPOISON 0
#endif

static inline int PageUptodate(struct page *page)
{
	int ret = test_bit(PG_uptodate, &(page)->flags);

	/*
	 * Must ensure that the data we read out of the page is loaded
	 * _after_ we've loaded page->flags to check for PageUptodate.
	 * We can skip the barrier if the page is not uptodate, because
	 * we wouldn't be reading anything from it.
	 *
	 * See SetPageUptodate() for the other side of the story.
	 */
	if (ret)
		smp_rmb();

	return ret;
}

static inline void __SetPageUptodate(struct page *page)
{
	smp_wmb();
	__set_bit(PG_uptodate, &(page)->flags);
}

static inline void SetPageUptodate(struct page *page)
{
#ifdef CONFIG_S390
	if (!test_and_set_bit(PG_uptodate, &page->flags))
		page_clear_dirty(page);
#else
	/*
	 * Memory barrier must be issued before setting the PG_uptodate bit,
	 * so that all previous stores issued in order to bring the page
	 * uptodate are actually visible before PageUptodate becomes true.
	 *
	 * s390 doesn't need an explicit smp_wmb here because the test and
	 * set bit already provides full barriers.
	 */
	smp_wmb();
	set_bit(PG_uptodate, &(page)->flags);
#endif
}

CLEARPAGEFLAG(Uptodate, uptodate)

extern void cancel_dirty_page(struct page *page, unsigned int account_size);

int test_clear_page_writeback(struct page *page);
int test_set_page_writeback(struct page *page);

static inline void set_page_writeback(struct page *page)
{
	test_set_page_writeback(page);
}

#ifdef CONFIG_PAGEFLAGS_EXTENDED
/*
 * System with lots of page flags available. This allows separate
 * flags for PageHead() and PageTail() checks of compound pages so that bit
 * tests can be used in performance sensitive paths. PageCompound is
 * generally not used in hot code paths.
 */
__PAGEFLAG(Head, head)
__PAGEFLAG(Tail, tail)

static inline int PageCompound(struct page *page)
{
	return page->flags & ((1L << PG_head) | (1L << PG_tail));

}
#else
/*
 * Reduce page flag use as much as possible by overlapping
 * compound page flags with the flags used for page cache pages. Possible
 * because PageCompound is always set for compound pages and not for
 * pages on the LRU and/or pagecache.
 */
TESTPAGEFLAG(Compound, compound)
__PAGEFLAG(Head, compound)

/*
 * PG_reclaim is used in combination with PG_compound to mark the
 * head and tail of a compound page. This saves one page flag
 * but makes it impossible to use compound pages for the page cache.
 * The PG_reclaim bit would have to be used for reclaim or readahead
 * if compound pages enter the page cache.
 *
 * PG_compound & PG_reclaim	=> Tail page
 * PG_compound & ~PG_reclaim	=> Head page
 */
#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))

static inline int PageTail(struct page *page)
{
	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
}

static inline void __SetPageTail(struct page *page)
{
	page->flags |= PG_head_tail_mask;
}

static inline void __ClearPageTail(struct page *page)
{
	page->flags &= ~PG_head_tail_mask;
}

#endif /* !PAGEFLAGS_EXTENDED */

#ifdef CONFIG_MMU
#define __PG_MLOCKED		(1 << PG_mlocked)
#else
#define __PG_MLOCKED		0
#endif

/*
 * 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 \
	(1 << PG_lru	 | 1 << PG_locked    | \
	 1 << PG_private | 1 << PG_private_2 | \
	 1 << PG_buddy	 | 1 << PG_writeback | 1 << PG_reserved | \
	 1 << PG_slab	 | 1 << PG_swapcache | 1 << PG_active | \
	 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON)

/*
 * Flags checked when a page is prepped for return by the page allocator.
 * Pages being prepped should not have any flags set.  It they are set,
 * there has been a kernel bug or struct page corruption.
 */
#define PAGE_FLAGS_CHECK_AT_PREP	((1 << NR_PAGEFLAGS) - 1)

#define PAGE_FLAGS_PRIVATE				\
	(1 << PG_private | 1 << 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);
}

#endif /* !__GENERATING_BOUNDS_H */

#endif	/* PAGE_FLAGS_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Macros for manipulating and testing page->flags
	3	*/
	4
	5	#ifndef PAGE_FLAGS_H
	6	#define PAGE_FLAGS_H
	7
f886ed44	8	#include <linux/types.h>
9223b419	9	#ifndef __GENERATING_BOUNDS_H
6d777953	10	#include <linux/mm_types.h>
9223b419 CL	11	#include <linux/bounds.h>
9223b419 CL	12	#endif /* !__GENERATING_BOUNDS_H */
f886ed44	13
1da177e4 LT	14	/*
	15	* Various page->flags bits:
	16	*
	17	* PG_reserved is set for special pages, which can never be swapped out. Some
	18	* of them might not even exist (eg empty_bad_page)...
	19	*
da6052f7 NP	20	* The PG_private bitflag is set on pagecache pages if they contain filesystem
	21	* specific data (which is normally at page->private). It can be used by
	22	* private allocations for its own usage.
1da177e4	23	*
da6052f7 NP	24	* During initiation of disk I/O, PG_locked is set. This bit is set before I/O
	25	* and cleared when writeback _starts_ or when read _completes_. PG_writeback
	26	* is set before writeback starts and cleared when it finishes.
	27	*
	28	* PG_locked also pins a page in pagecache, and blocks truncation of the file
	29	* while it is held.
	30	*
	31	* page_waitqueue(page) is a wait queue of all tasks waiting for the page
	32	* to become unlocked.
1da177e4 LT	33	*
	34	* PG_uptodate tells whether the page's contents is valid. When a read
	35	* completes, the page becomes uptodate, unless a disk I/O error happened.
	36	*
da6052f7 NP	37	* PG_referenced, PG_reclaim are used for page reclaim for anonymous and
da6052f7 NP	38	* file-backed pagecache (see mm/vmscan.c).
1da177e4 LT	39	*
	40	* PG_error is set to indicate that an I/O error occurred on this page.
	41	*
	42	* PG_arch_1 is an architecture specific page state bit. The generic code
	43	* guarantees that this bit is cleared for a page when it first is entered into
	44	* the page cache.
	45	*
	46	* PG_highmem pages are not permanently mapped into the kernel virtual address
	47	* space, they need to be kmapped separately for doing IO on the pages. The
	48	* struct page (these bits with information) are always mapped into kernel
	49	* address space...
da6052f7 NP	50	*
	51	* PG_buddy is set to indicate that the page is free and in the buddy system
	52	* (see mm/page_alloc.c).
	53	*
d466f2fc AK	54	* PG_hwpoison indicates that a page got corrupted in hardware and contains
	55	* data with incorrect ECC bits that triggered a machine check. Accessing is
	56	* not safe since it may cause another machine check. Don't touch!
1da177e4 LT	57	*/
	58
	59	/*
	60	* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3 AW	61	* locked- and dirty-page accounting.
	62	*
	63	* The page flags field is split into two parts, the main flags area
	64	* which extends from the low bits upwards, and the fields area which
	65	* extends from the high bits downwards.
	66	*
	67	* \| FIELD \| ... \| FLAGS \|
9223b419 CL	68	* N-1 ^ 0
9223b419 CL	69	* (NR_PAGEFLAGS)
91fc8ab3	70	*
9223b419 CL	71	* The fields area is reserved for fields mapping zone, node (for NUMA) and
	72	* SPARSEMEM section (for variants of SPARSEMEM that require section ids like
	73	* SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
1da177e4	74	*/
e2683181 CL	75	enum pageflags {
	76	PG_locked, /* Page is locked. Don't touch. */
	77	PG_error,
	78	PG_referenced,
	79	PG_uptodate,
	80	PG_dirty,
	81	PG_lru,
	82	PG_active,
	83	PG_slab,
	84	PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
e2683181 CL	85	PG_arch_1,
	86	PG_reserved,
	87	PG_private, /* If pagecache, has fs-private data */
266cf658	88	PG_private_2, /* If pagecache, has fs aux data */
e2683181	89	PG_writeback, /* Page is under writeback */
e20b8cca CL	90	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	91	PG_head, /* A head page */
	92	PG_tail, /* A tail page */
	93	#else
e2683181	94	PG_compound, /* A compound page */
e20b8cca	95	#endif
e2683181 CL	96	PG_swapcache, /* Swap page: swp_entry_t in private */
	97	PG_mappedtodisk, /* Has blocks allocated on-disk */
	98	PG_reclaim, /* To be reclaimed asap */
e2683181	99	PG_buddy, /* Page is free, on buddy lists */
b2e18538	100	PG_swapbacked, /* Page is backed by RAM/swap */
894bc310	101	PG_unevictable, /* Page is "unevictable" */
af8e3354	102	#ifdef CONFIG_MMU
b291f000	103	PG_mlocked, /* Page is vma mlocked */
894bc310	104	#endif
46cf98cd	105	#ifdef CONFIG_ARCH_USES_PG_UNCACHED
602c4d11	106	PG_uncached, /* Page has been mapped as uncached */
d466f2fc AK	107	#endif
	108	#ifdef CONFIG_MEMORY_FAILURE
	109	PG_hwpoison, /* hardware poisoned page. Don't touch */
f886ed44	110	#endif
0cad47cf AW	111	__NR_PAGEFLAGS,
	112
	113	/* Filesystems */
	114	PG_checked = PG_owner_priv_1,
	115
266cf658 DH	116	/* Two page bits are conscripted by FS-Cache to maintain local caching
	117	* state. These bits are set on pages belonging to the netfs's inodes
	118	* when those inodes are being locally cached.
	119	*/
	120	PG_fscache = PG_private_2, /* page backed by cache */
	121
0cad47cf AW	122	/* XEN */
	123	PG_pinned = PG_owner_priv_1,
	124	PG_savepinned = PG_dirty,
8a38082d	125
9023cb7e	126	/* SLOB */
9023cb7e AW	127	PG_slob_free = PG_private,
9023cb7e AW	128
8a38082d AW	129	/* SLUB */
	130	PG_slub_frozen = PG_active,
	131	PG_slub_debug = PG_error,
e2683181	132	};
1da177e4	133
9223b419 CL	134	#ifndef __GENERATING_BOUNDS_H
9223b419 CL	135
f94a62e9 CL	136	/*
	137	* Macros to create function definitions for page flags
	138	*/
	139	#define TESTPAGEFLAG(uname, lname) \
	140	static inline int Page##uname(struct page *page) \
	141	{ return test_bit(PG_##lname, &page->flags); }
	142
	143	#define SETPAGEFLAG(uname, lname) \
	144	static inline void SetPage##uname(struct page *page) \
	145	{ set_bit(PG_##lname, &page->flags); }
	146
	147	#define CLEARPAGEFLAG(uname, lname) \
	148	static inline void ClearPage##uname(struct page *page) \
	149	{ clear_bit(PG_##lname, &page->flags); }
	150
	151	#define __SETPAGEFLAG(uname, lname) \
	152	static inline void __SetPage##uname(struct page *page) \
	153	{ __set_bit(PG_##lname, &page->flags); }
	154
	155	#define __CLEARPAGEFLAG(uname, lname) \
	156	static inline void __ClearPage##uname(struct page *page) \
	157	{ __clear_bit(PG_##lname, &page->flags); }
	158
	159	#define TESTSETFLAG(uname, lname) \
	160	static inline int TestSetPage##uname(struct page *page) \
	161	{ return test_and_set_bit(PG_##lname, &page->flags); }
	162
	163	#define TESTCLEARFLAG(uname, lname) \
	164	static inline int TestClearPage##uname(struct page *page) \
	165	{ return test_and_clear_bit(PG_##lname, &page->flags); }
	166
451ea25d JW	167	#define __TESTCLEARFLAG(uname, lname) \
	168	static inline int __TestClearPage##uname(struct page *page) \
	169	{ return __test_and_clear_bit(PG_##lname, &page->flags); }
f94a62e9 CL	170
	171	#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	172	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
	173
	174	#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	175	__SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
	176
ec7cade8 CL	177	#define PAGEFLAG_FALSE(uname) \
	178	static inline int Page##uname(struct page *page) \
	179	{ return 0; }
	180
f94a62e9 CL	181	#define TESTSCFLAG(uname, lname) \
	182	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
	183
8a7a8544 LS	184	#define SETPAGEFLAG_NOOP(uname) \
	185	static inline void SetPage##uname(struct page *page) { }
	186
	187	#define CLEARPAGEFLAG_NOOP(uname) \
	188	static inline void ClearPage##uname(struct page *page) { }
	189
	190	#define __CLEARPAGEFLAG_NOOP(uname) \
	191	static inline void __ClearPage##uname(struct page *page) { }
	192
	193	#define TESTCLEARFLAG_FALSE(uname) \
	194	static inline int TestClearPage##uname(struct page *page) { return 0; }
	195
451ea25d JW	196	#define __TESTCLEARFLAG_FALSE(uname) \
	197	static inline int __TestClearPage##uname(struct page *page) { return 0; }
	198
6a1e7f77 CL	199	struct page; /* forward declaration */
6a1e7f77 CL	200
03fb3d2a	201	TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
6a1e7f77 CL	202	PAGEFLAG(Error, error)
	203	PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
	204	PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
	205	PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
	206	PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
894bc310	207	TESTCLEARFLAG(Active, active)
6a1e7f77	208	__PAGEFLAG(Slab, slab)
0cad47cf AW	209	PAGEFLAG(Checked, checked) /* Used by some filesystems */
	210	PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
	211	PAGEFLAG(SavePinned, savepinned); /* Xen */
6a1e7f77	212	PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
b2e18538	213	PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
6a1e7f77	214
9023cb7e AW	215	__PAGEFLAG(SlobFree, slob_free)
9023cb7e AW	216
8a38082d AW	217	__PAGEFLAG(SlubFrozen, slub_frozen)
	218	__PAGEFLAG(SlubDebug, slub_debug)
	219
266cf658 DH	220	/*
	221	* Private page markings that may be used by the filesystem that owns the page
	222	* for its own purposes.
	223	* - PG_private and PG_private_2 cause releasepage() and co to be invoked
	224	*/
	225	PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
	226	__CLEARPAGEFLAG(Private, private)
	227	PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
	228	PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
	229
6a1e7f77 CL	230	/*
	231	* Only test-and-set exist for PG_writeback. The unconditional operators are
	232	* risky: they bypass page accounting.
	233	*/
	234	TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
	235	__PAGEFLAG(Buddy, buddy)
	236	PAGEFLAG(MappedToDisk, mappedtodisk)
	237
	238	/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
	239	PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
0a128b2b	240	PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
6a1e7f77 CL	241
6a1e7f77 CL	242	#ifdef CONFIG_HIGHMEM
1da177e4	243	/*
6a1e7f77 CL	244	* Must use a macro here due to header dependency issues. page_zone() is not
6a1e7f77 CL	245	* available at this point.
1da177e4	246	*/
0a128b2b	247	#define PageHighMem(__p) is_highmem(page_zone(__p))
6a1e7f77	248	#else
ec7cade8	249	PAGEFLAG_FALSE(HighMem)
6a1e7f77 CL	250	#endif
	251
	252	#ifdef CONFIG_SWAP
	253	PAGEFLAG(SwapCache, swapcache)
	254	#else
ec7cade8	255	PAGEFLAG_FALSE(SwapCache)
6d91add0	256	SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
6a1e7f77 CL	257	#endif
6a1e7f77 CL	258
894bc310 LS	259	PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
894bc310 LS	260	TESTCLEARFLAG(Unevictable, unevictable)
b291f000	261
af8e3354	262	#ifdef CONFIG_MMU
b291f000	263	PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
451ea25d	264	TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
894bc310	265	#else
451ea25d JW	266	PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked)
451ea25d JW	267	TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
894bc310 LS	268	#endif
894bc310 LS	269
46cf98cd	270	#ifdef CONFIG_ARCH_USES_PG_UNCACHED
6a1e7f77	271	PAGEFLAG(Uncached, uncached)
602c4d11	272	#else
ec7cade8	273	PAGEFLAG_FALSE(Uncached)
6a1e7f77	274	#endif
1da177e4	275
d466f2fc AK	276	#ifdef CONFIG_MEMORY_FAILURE
	277	PAGEFLAG(HWPoison, hwpoison)
	278	TESTSETFLAG(HWPoison, hwpoison)
	279	#define __PG_HWPOISON (1UL << PG_hwpoison)
	280	#else
	281	PAGEFLAG_FALSE(HWPoison)
	282	#define __PG_HWPOISON 0
	283	#endif
	284
0ed361de NP	285	static inline int PageUptodate(struct page *page)
	286	{
	287	int ret = test_bit(PG_uptodate, &(page)->flags);
	288
	289	/*
	290	* Must ensure that the data we read out of the page is loaded
	291	* _after_ we've loaded page->flags to check for PageUptodate.
	292	* We can skip the barrier if the page is not uptodate, because
	293	* we wouldn't be reading anything from it.
	294	*
	295	* See SetPageUptodate() for the other side of the story.
	296	*/
	297	if (ret)
	298	smp_rmb();
	299
	300	return ret;
	301	}
	302
	303	static inline void __SetPageUptodate(struct page *page)
	304	{
	305	smp_wmb();
	306	__set_bit(PG_uptodate, &(page)->flags);
0ed361de NP	307	}
0ed361de NP	308
2dcea57a HC	309	static inline void SetPageUptodate(struct page *page)
2dcea57a HC	310	{
0ed361de	311	#ifdef CONFIG_S390
2dcea57a	312	if (!test_and_set_bit(PG_uptodate, &page->flags))
6c210482	313	page_clear_dirty(page);
f6ac2354	314	#else
0ed361de NP	315	/*
	316	* Memory barrier must be issued before setting the PG_uptodate bit,
	317	* so that all previous stores issued in order to bring the page
	318	* uptodate are actually visible before PageUptodate becomes true.
	319	*
	320	* s390 doesn't need an explicit smp_wmb here because the test and
	321	* set bit already provides full barriers.
	322	*/
	323	smp_wmb();
	324	set_bit(PG_uptodate, &(page)->flags);
1da177e4	325	#endif
0ed361de NP	326	}
0ed361de NP	327
6a1e7f77	328	CLEARPAGEFLAG(Uptodate, uptodate)
1da177e4	329
6a1e7f77	330	extern void cancel_dirty_page(struct page *page, unsigned int account_size);
d77c2d7c	331
6a1e7f77 CL	332	int test_clear_page_writeback(struct page *page);
6a1e7f77 CL	333	int test_set_page_writeback(struct page *page);
1da177e4	334
6a1e7f77 CL	335	static inline void set_page_writeback(struct page *page)
	336	{
	337	test_set_page_writeback(page);
	338	}
1da177e4	339
e20b8cca CL	340	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	341	/*
	342	* System with lots of page flags available. This allows separate
	343	* flags for PageHead() and PageTail() checks of compound pages so that bit
	344	* tests can be used in performance sensitive paths. PageCompound is
	345	* generally not used in hot code paths.
	346	*/
	347	__PAGEFLAG(Head, head)
	348	__PAGEFLAG(Tail, tail)
	349
	350	static inline int PageCompound(struct page *page)
	351	{
	352	return page->flags & ((1L << PG_head) \| (1L << PG_tail));
	353
	354	}
	355	#else
	356	/*
	357	* Reduce page flag use as much as possible by overlapping
	358	* compound page flags with the flags used for page cache pages. Possible
	359	* because PageCompound is always set for compound pages and not for
	360	* pages on the LRU and/or pagecache.
	361	*/
6a1e7f77 CL	362	TESTPAGEFLAG(Compound, compound)
6a1e7f77 CL	363	__PAGEFLAG(Head, compound)
1da177e4	364
d85f3385	365	/*
6d777953	366	* PG_reclaim is used in combination with PG_compound to mark the
6a1e7f77 CL	367	* head and tail of a compound page. This saves one page flag
	368	* but makes it impossible to use compound pages for the page cache.
	369	* The PG_reclaim bit would have to be used for reclaim or readahead
	370	* if compound pages enter the page cache.
6d777953 CL	371	*
	372	* PG_compound & PG_reclaim => Tail page
	373	* PG_compound & ~PG_reclaim => Head page
d85f3385	374	*/
6d777953 CL	375	#define PG_head_tail_mask ((1L << PG_compound) \| (1L << PG_reclaim))
6d777953 CL	376
6a1e7f77 CL	377	static inline int PageTail(struct page *page)
	378	{
	379	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
	380	}
6d777953 CL	381
	382	static inline void __SetPageTail(struct page *page)
	383	{
	384	page->flags \|= PG_head_tail_mask;
	385	}
	386
	387	static inline void __ClearPageTail(struct page *page)
	388	{
	389	page->flags &= ~PG_head_tail_mask;
	390	}
	391
e20b8cca	392	#endif /* !PAGEFLAGS_EXTENDED */
dfa7e20c	393
af8e3354	394	#ifdef CONFIG_MMU
33925b25 DH	395	#define __PG_MLOCKED (1 << PG_mlocked)
33925b25 DH	396	#else
b291f000	397	#define __PG_MLOCKED 0
894bc310 LS	398	#endif
894bc310 LS	399
dfa7e20c RA	400	/*
	401	* Flags checked when a page is freed. Pages being freed should not have
	402	* these flags set. It they are, there is a problem.
	403	*/
79f4b7bf	404	#define PAGE_FLAGS_CHECK_AT_FREE \
266cf658 DH	405	(1 << PG_lru \| 1 << PG_locked \| \
	406	1 << PG_private \| 1 << PG_private_2 \| \
	407	1 << PG_buddy \| 1 << PG_writeback \| 1 << PG_reserved \| \
	408	1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active \| \
d466f2fc	409	1 << PG_unevictable \| __PG_MLOCKED \| __PG_HWPOISON)
dfa7e20c RA	410
	411	/*
	412	* Flags checked when a page is prepped for return by the page allocator.
79f4b7bf HD	413	* Pages being prepped should not have any flags set. It they are set,
79f4b7bf HD	414	* there has been a kernel bug or struct page corruption.
dfa7e20c	415	*/
79f4b7bf	416	#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
dfa7e20c	417
edcf4748 JW	418	#define PAGE_FLAGS_PRIVATE \
edcf4748 JW	419	(1 << PG_private \| 1 << PG_private_2)
266cf658 DH	420	/**
	421	* page_has_private - Determine if page has private stuff
	422	* @page: The page to be checked
	423	*
	424	* Determine if a page has private stuff, indicating that release routines
	425	* should be invoked upon it.
	426	*/
edcf4748 JW	427	static inline int page_has_private(struct page *page)
	428	{
	429	return !!(page->flags & PAGE_FLAGS_PRIVATE);
	430	}
	431
	432	#endif /* !__GENERATING_BOUNDS_H */
266cf658	433
1da177e4	434	#endif /* PAGE_FLAGS_H */