[GitHub/mt8127/android_kernel_alcatel_ttab.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).
 *
 */

/*
 * 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_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 */
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
	PG_uncached,		/* Page has been mapped as uncached */
#endif
	__NR_PAGEFLAGS,

	/* Filesystems */
	PG_checked = PG_owner_priv_1,

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

	/* SLOB */
	PG_slob_page = PG_active,
	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 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)

struct page;	/* forward declaration */

TESTPAGEFLAG(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)
__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(Private, private) __CLEARPAGEFLAG(Private, private)
	__SETPAGEFLAG(Private, private)
PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)

__PAGEFLAG(SlobPage, slob_page)
__PAGEFLAG(SlobFree, slob_free)

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

/*
 * 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)
#endif

#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PAGEFLAG(Uncached, uncached)
#else
PAGEFLAG_FALSE(Uncached)
#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 */

#define PAGE_FLAGS	(1 << PG_lru   | 1 << PG_private   | 1 << PG_locked | \
			 1 << PG_buddy | 1 << PG_writeback | \
			 1 << PG_slab  | 1 << PG_swapcache | 1 << PG_active)

/*
 * Flags checked in bad_page().  Pages on the free list should not have
 * these flags set.  It they are, there is a problem.
 */
#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS | \
		1 << PG_reclaim | 1 << PG_dirty | 1 << PG_swapbacked)

/*
 * 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 (PAGE_FLAGS | 1 << PG_reserved)

/*
 * Flags checked when a page is prepped for return by the page allocator.
 * Pages being prepped should not have these flags set.  It they are, there
 * is a problem.
 */
#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS | \
		1 << PG_reserved | 1 << PG_dirty | 1 << PG_swapbacked)

#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	*
1da177e4 LT	54	*/
	55
	56	/*
	57	* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3 AW	58	* locked- and dirty-page accounting.
	59	*
	60	* The page flags field is split into two parts, the main flags area
	61	* which extends from the low bits upwards, and the fields area which
	62	* extends from the high bits downwards.
	63	*
	64	* \| FIELD \| ... \| FLAGS \|
9223b419 CL	65	* N-1 ^ 0
9223b419 CL	66	* (NR_PAGEFLAGS)
91fc8ab3	67	*
9223b419 CL	68	* The fields area is reserved for fields mapping zone, node (for NUMA) and
	69	* SPARSEMEM section (for variants of SPARSEMEM that require section ids like
	70	* SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
1da177e4	71	*/
e2683181 CL	72	enum pageflags {
	73	PG_locked, /* Page is locked. Don't touch. */
	74	PG_error,
	75	PG_referenced,
	76	PG_uptodate,
	77	PG_dirty,
	78	PG_lru,
	79	PG_active,
	80	PG_slab,
	81	PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
e2683181 CL	82	PG_arch_1,
	83	PG_reserved,
	84	PG_private, /* If pagecache, has fs-private data */
	85	PG_writeback, /* Page is under writeback */
e20b8cca CL	86	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	87	PG_head, /* A head page */
	88	PG_tail, /* A tail page */
	89	#else
e2683181	90	PG_compound, /* A compound page */
e20b8cca	91	#endif
e2683181 CL	92	PG_swapcache, /* Swap page: swp_entry_t in private */
	93	PG_mappedtodisk, /* Has blocks allocated on-disk */
	94	PG_reclaim, /* To be reclaimed asap */
e2683181	95	PG_buddy, /* Page is free, on buddy lists */
b2e18538	96	PG_swapbacked, /* Page is backed by RAM/swap */
602c4d11 CL	97	#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
602c4d11 CL	98	PG_uncached, /* Page has been mapped as uncached */
f886ed44	99	#endif
0cad47cf AW	100	__NR_PAGEFLAGS,
	101
	102	/* Filesystems */
	103	PG_checked = PG_owner_priv_1,
	104
	105	/* XEN */
	106	PG_pinned = PG_owner_priv_1,
	107	PG_savepinned = PG_dirty,
8a38082d	108
9023cb7e AW	109	/* SLOB */
	110	PG_slob_page = PG_active,
	111	PG_slob_free = PG_private,
	112
8a38082d AW	113	/* SLUB */
	114	PG_slub_frozen = PG_active,
	115	PG_slub_debug = PG_error,
e2683181	116	};
1da177e4	117
9223b419 CL	118	#ifndef __GENERATING_BOUNDS_H
9223b419 CL	119
f94a62e9 CL	120	/*
	121	* Macros to create function definitions for page flags
	122	*/
	123	#define TESTPAGEFLAG(uname, lname) \
	124	static inline int Page##uname(struct page *page) \
	125	{ return test_bit(PG_##lname, &page->flags); }
	126
	127	#define SETPAGEFLAG(uname, lname) \
	128	static inline void SetPage##uname(struct page *page) \
	129	{ set_bit(PG_##lname, &page->flags); }
	130
	131	#define CLEARPAGEFLAG(uname, lname) \
	132	static inline void ClearPage##uname(struct page *page) \
	133	{ clear_bit(PG_##lname, &page->flags); }
	134
	135	#define __SETPAGEFLAG(uname, lname) \
	136	static inline void __SetPage##uname(struct page *page) \
	137	{ __set_bit(PG_##lname, &page->flags); }
	138
	139	#define __CLEARPAGEFLAG(uname, lname) \
	140	static inline void __ClearPage##uname(struct page *page) \
	141	{ __clear_bit(PG_##lname, &page->flags); }
	142
	143	#define TESTSETFLAG(uname, lname) \
	144	static inline int TestSetPage##uname(struct page *page) \
	145	{ return test_and_set_bit(PG_##lname, &page->flags); }
	146
	147	#define TESTCLEARFLAG(uname, lname) \
	148	static inline int TestClearPage##uname(struct page *page) \
	149	{ return test_and_clear_bit(PG_##lname, &page->flags); }
	150
	151
	152	#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	153	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
	154
	155	#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	156	__SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
	157
ec7cade8 CL	158	#define PAGEFLAG_FALSE(uname) \
	159	static inline int Page##uname(struct page *page) \
	160	{ return 0; }
	161
f94a62e9 CL	162	#define TESTSCFLAG(uname, lname) \
	163	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
	164
6a1e7f77 CL	165	struct page; /* forward declaration */
6a1e7f77 CL	166
529ae9aa	167	TESTPAGEFLAG(Locked, locked)
6a1e7f77 CL	168	PAGEFLAG(Error, error)
	169	PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
	170	PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
	171	PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
	172	PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
	173	__PAGEFLAG(Slab, slab)
0cad47cf AW	174	PAGEFLAG(Checked, checked) /* Used by some filesystems */
	175	PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
	176	PAGEFLAG(SavePinned, savepinned); /* Xen */
6a1e7f77 CL	177	PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
	178	PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
	179	__SETPAGEFLAG(Private, private)
b2e18538	180	PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
6a1e7f77	181
9023cb7e AW	182	__PAGEFLAG(SlobPage, slob_page)
	183	__PAGEFLAG(SlobFree, slob_free)
	184
8a38082d AW	185	__PAGEFLAG(SlubFrozen, slub_frozen)
	186	__PAGEFLAG(SlubDebug, slub_debug)
	187
6a1e7f77 CL	188	/*
	189	* Only test-and-set exist for PG_writeback. The unconditional operators are
	190	* risky: they bypass page accounting.
	191	*/
	192	TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
	193	__PAGEFLAG(Buddy, buddy)
	194	PAGEFLAG(MappedToDisk, mappedtodisk)
	195
	196	/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
	197	PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
0a128b2b	198	PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
6a1e7f77 CL	199
6a1e7f77 CL	200	#ifdef CONFIG_HIGHMEM
1da177e4	201	/*
6a1e7f77 CL	202	* Must use a macro here due to header dependency issues. page_zone() is not
6a1e7f77 CL	203	* available at this point.
1da177e4	204	*/
0a128b2b	205	#define PageHighMem(__p) is_highmem(page_zone(__p))
6a1e7f77	206	#else
ec7cade8	207	PAGEFLAG_FALSE(HighMem)
6a1e7f77 CL	208	#endif
	209
	210	#ifdef CONFIG_SWAP
	211	PAGEFLAG(SwapCache, swapcache)
	212	#else
ec7cade8	213	PAGEFLAG_FALSE(SwapCache)
6a1e7f77 CL	214	#endif
6a1e7f77 CL	215
602c4d11	216	#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
6a1e7f77	217	PAGEFLAG(Uncached, uncached)
602c4d11	218	#else
ec7cade8	219	PAGEFLAG_FALSE(Uncached)
6a1e7f77	220	#endif
1da177e4	221
0ed361de NP	222	static inline int PageUptodate(struct page *page)
	223	{
	224	int ret = test_bit(PG_uptodate, &(page)->flags);
	225
	226	/*
	227	* Must ensure that the data we read out of the page is loaded
	228	* _after_ we've loaded page->flags to check for PageUptodate.
	229	* We can skip the barrier if the page is not uptodate, because
	230	* we wouldn't be reading anything from it.
	231	*
	232	* See SetPageUptodate() for the other side of the story.
	233	*/
	234	if (ret)
	235	smp_rmb();
	236
	237	return ret;
	238	}
	239
	240	static inline void __SetPageUptodate(struct page *page)
	241	{
	242	smp_wmb();
	243	__set_bit(PG_uptodate, &(page)->flags);
0ed361de NP	244	}
0ed361de NP	245
2dcea57a HC	246	static inline void SetPageUptodate(struct page *page)
2dcea57a HC	247	{
0ed361de	248	#ifdef CONFIG_S390
2dcea57a	249	if (!test_and_set_bit(PG_uptodate, &page->flags))
6c210482	250	page_clear_dirty(page);
f6ac2354	251	#else
0ed361de NP	252	/*
	253	* Memory barrier must be issued before setting the PG_uptodate bit,
	254	* so that all previous stores issued in order to bring the page
	255	* uptodate are actually visible before PageUptodate becomes true.
	256	*
	257	* s390 doesn't need an explicit smp_wmb here because the test and
	258	* set bit already provides full barriers.
	259	*/
	260	smp_wmb();
	261	set_bit(PG_uptodate, &(page)->flags);
1da177e4	262	#endif
0ed361de NP	263	}
0ed361de NP	264
6a1e7f77	265	CLEARPAGEFLAG(Uptodate, uptodate)
1da177e4	266
6a1e7f77	267	extern void cancel_dirty_page(struct page *page, unsigned int account_size);
d77c2d7c	268
6a1e7f77 CL	269	int test_clear_page_writeback(struct page *page);
6a1e7f77 CL	270	int test_set_page_writeback(struct page *page);
1da177e4	271
6a1e7f77 CL	272	static inline void set_page_writeback(struct page *page)
	273	{
	274	test_set_page_writeback(page);
	275	}
1da177e4	276
e20b8cca CL	277	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	278	/*
	279	* System with lots of page flags available. This allows separate
	280	* flags for PageHead() and PageTail() checks of compound pages so that bit
	281	* tests can be used in performance sensitive paths. PageCompound is
	282	* generally not used in hot code paths.
	283	*/
	284	__PAGEFLAG(Head, head)
	285	__PAGEFLAG(Tail, tail)
	286
	287	static inline int PageCompound(struct page *page)
	288	{
	289	return page->flags & ((1L << PG_head) \| (1L << PG_tail));
	290
	291	}
	292	#else
	293	/*
	294	* Reduce page flag use as much as possible by overlapping
	295	* compound page flags with the flags used for page cache pages. Possible
	296	* because PageCompound is always set for compound pages and not for
	297	* pages on the LRU and/or pagecache.
	298	*/
6a1e7f77 CL	299	TESTPAGEFLAG(Compound, compound)
6a1e7f77 CL	300	__PAGEFLAG(Head, compound)
1da177e4	301
d85f3385	302	/*
6d777953	303	* PG_reclaim is used in combination with PG_compound to mark the
6a1e7f77 CL	304	* head and tail of a compound page. This saves one page flag
	305	* but makes it impossible to use compound pages for the page cache.
	306	* The PG_reclaim bit would have to be used for reclaim or readahead
	307	* if compound pages enter the page cache.
6d777953 CL	308	*
	309	* PG_compound & PG_reclaim => Tail page
	310	* PG_compound & ~PG_reclaim => Head page
d85f3385	311	*/
6d777953 CL	312	#define PG_head_tail_mask ((1L << PG_compound) \| (1L << PG_reclaim))
6d777953 CL	313
6a1e7f77 CL	314	static inline int PageTail(struct page *page)
	315	{
	316	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
	317	}
6d777953 CL	318
	319	static inline void __SetPageTail(struct page *page)
	320	{
	321	page->flags \|= PG_head_tail_mask;
	322	}
	323
	324	static inline void __ClearPageTail(struct page *page)
	325	{
	326	page->flags &= ~PG_head_tail_mask;
	327	}
	328
e20b8cca	329	#endif /* !PAGEFLAGS_EXTENDED */
dfa7e20c RA	330
	331	#define PAGE_FLAGS (1 << PG_lru \| 1 << PG_private \| 1 << PG_locked \| \
	332	1 << PG_buddy \| 1 << PG_writeback \| \
	333	1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active)
	334
	335	/*
	336	* Flags checked in bad_page(). Pages on the free list should not have
	337	* these flags set. It they are, there is a problem.
	338	*/
b2e18538 RR	339	#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS \| \
b2e18538 RR	340	1 << PG_reclaim \| 1 << PG_dirty \| 1 << PG_swapbacked)
dfa7e20c RA	341
	342	/*
	343	* Flags checked when a page is freed. Pages being freed should not have
	344	* these flags set. It they are, there is a problem.
	345	*/
	346	#define PAGE_FLAGS_CHECK_AT_FREE (PAGE_FLAGS \| 1 << PG_reserved)
	347
	348	/*
	349	* Flags checked when a page is prepped for return by the page allocator.
	350	* Pages being prepped should not have these flags set. It they are, there
	351	* is a problem.
	352	*/
b2e18538 RR	353	#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS \| \
b2e18538 RR	354	1 << PG_reserved \| 1 << PG_dirty \| 1 << PG_swapbacked)
dfa7e20c	355
9223b419	356	#endif /* !__GENERATING_BOUNDS_H */
1da177e4	357	#endif /* PAGE_FLAGS_H */