[deliverable/linux.git] / include / linux / backing-dev.h

/*
 * include/linux/backing-dev.h
 *
 * low-level device information and state which is propagated up through
 * to high-level code.
 */

#ifndef _LINUX_BACKING_DEV_H
#define _LINUX_BACKING_DEV_H

#include <linux/percpu_counter.h>
#include <linux/log2.h>
#include <linux/proportions.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <asm/atomic.h>

struct page;
struct device;
struct dentry;

/*
 * Bits in backing_dev_info.state
 */
enum bdi_state {
	BDI_pending,		/* On its way to being activated */
	BDI_wb_alloc,		/* Default embedded wb allocated */
	BDI_async_congested,	/* The async (write) queue is getting full */
	BDI_sync_congested,	/* The sync queue is getting full */
	BDI_registered,		/* bdi_register() was done */
	BDI_unused,		/* Available bits start here */
};

typedef int (congested_fn)(void *, int);

enum bdi_stat_item {
	BDI_RECLAIMABLE,
	BDI_WRITEBACK,
	NR_BDI_STAT_ITEMS
};

#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))

struct bdi_writeback {
	struct list_head list;			/* hangs off the bdi */

	struct backing_dev_info *bdi;		/* our parent bdi */
	unsigned int nr;

	unsigned long last_old_flush;		/* last old data flush */

	struct task_struct	*task;		/* writeback task */
	struct list_head	b_dirty;	/* dirty inodes */
	struct list_head	b_io;		/* parked for writeback */
	struct list_head	b_more_io;	/* parked for more writeback */
};

struct backing_dev_info {
	struct list_head bdi_list;
	struct rcu_head rcu_head;
	unsigned long ra_pages;	/* max readahead in PAGE_CACHE_SIZE units */
	unsigned long state;	/* Always use atomic bitops on this */
	unsigned int capabilities; /* Device capabilities */
	congested_fn *congested_fn; /* Function pointer if device is md/dm */
	void *congested_data;	/* Pointer to aux data for congested func */
	void (*unplug_io_fn)(struct backing_dev_info *, struct page *);
	void *unplug_io_data;

	char *name;

	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];

	struct prop_local_percpu completions;
	int dirty_exceeded;

	unsigned int min_ratio;
	unsigned int max_ratio, max_prop_frac;

	struct bdi_writeback wb;  /* default writeback info for this bdi */
	spinlock_t wb_lock;	  /* protects update side of wb_list */
	struct list_head wb_list; /* the flusher threads hanging off this bdi */
	unsigned long wb_mask;	  /* bitmask of registered tasks */
	unsigned int wb_cnt;	  /* number of registered tasks */

	struct list_head work_list;

	struct device *dev;

#ifdef CONFIG_DEBUG_FS
	struct dentry *debug_dir;
	struct dentry *debug_stats;
#endif
};

int bdi_init(struct backing_dev_info *bdi);
void bdi_destroy(struct backing_dev_info *bdi);

int bdi_register(struct backing_dev_info *bdi, struct device *parent,
		const char *fmt, ...);
int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
void bdi_unregister(struct backing_dev_info *bdi);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
int bdi_writeback_task(struct bdi_writeback *wb);
int bdi_has_dirty_io(struct backing_dev_info *bdi);

extern spinlock_t bdi_lock;
extern struct list_head bdi_list;

static inline int wb_has_dirty_io(struct bdi_writeback *wb)
{
	return !list_empty(&wb->b_dirty) ||
	       !list_empty(&wb->b_io) ||
	       !list_empty(&wb->b_more_io);
}

static inline void __add_bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item, s64 amount)
{
	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
}

static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	__add_bdi_stat(bdi, item, 1);
}

static inline void inc_bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	unsigned long flags;

	local_irq_save(flags);
	__inc_bdi_stat(bdi, item);
	local_irq_restore(flags);
}

static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	__add_bdi_stat(bdi, item, -1);
}

static inline void dec_bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	unsigned long flags;

	local_irq_save(flags);
	__dec_bdi_stat(bdi, item);
	local_irq_restore(flags);
}

static inline s64 bdi_stat(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
}

static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
}

static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
		enum bdi_stat_item item)
{
	s64 sum;
	unsigned long flags;

	local_irq_save(flags);
	sum = __bdi_stat_sum(bdi, item);
	local_irq_restore(flags);

	return sum;
}

extern void bdi_writeout_inc(struct backing_dev_info *bdi);

/*
 * maximal error of a stat counter.
 */
static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
{
#ifdef CONFIG_SMP
	return nr_cpu_ids * BDI_STAT_BATCH;
#else
	return 1;
#endif
}

int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);

/*
 * Flags in backing_dev_info::capability
 *
 * The first three flags control whether dirty pages will contribute to the
 * VM's accounting and whether writepages() should be called for dirty pages
 * (something that would not, for example, be appropriate for ramfs)
 *
 * WARNING: these flags are closely related and should not normally be
 * used separately.  The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
 * three flags into a single convenience macro.
 *
 * BDI_CAP_NO_ACCT_DIRTY:  Dirty pages shouldn't contribute to accounting
 * BDI_CAP_NO_WRITEBACK:   Don't write pages back
 * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
 *
 * These flags let !MMU mmap() govern direct device mapping vs immediate
 * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
 *
 * BDI_CAP_MAP_COPY:       Copy can be mapped (MAP_PRIVATE)
 * BDI_CAP_MAP_DIRECT:     Can be mapped directly (MAP_SHARED)
 * BDI_CAP_READ_MAP:       Can be mapped for reading
 * BDI_CAP_WRITE_MAP:      Can be mapped for writing
 * BDI_CAP_EXEC_MAP:       Can be mapped for execution
 *
 * BDI_CAP_SWAP_BACKED:    Count shmem/tmpfs objects as swap-backed.
 */
#define BDI_CAP_NO_ACCT_DIRTY	0x00000001
#define BDI_CAP_NO_WRITEBACK	0x00000002
#define BDI_CAP_MAP_COPY	0x00000004
#define BDI_CAP_MAP_DIRECT	0x00000008
#define BDI_CAP_READ_MAP	0x00000010
#define BDI_CAP_WRITE_MAP	0x00000020
#define BDI_CAP_EXEC_MAP	0x00000040
#define BDI_CAP_NO_ACCT_WB	0x00000080
#define BDI_CAP_SWAP_BACKED	0x00000100

#define BDI_CAP_VMFLAGS \
	(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)

#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	(BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)

#if defined(VM_MAYREAD) && \
	(BDI_CAP_READ_MAP != VM_MAYREAD || \
	 BDI_CAP_WRITE_MAP != VM_MAYWRITE || \
	 BDI_CAP_EXEC_MAP != VM_MAYEXEC)
#error please change backing_dev_info::capabilities flags
#endif

extern struct backing_dev_info default_backing_dev_info;
void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page);

int writeback_in_progress(struct backing_dev_info *bdi);

static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
{
	if (bdi->congested_fn)
		return bdi->congested_fn(bdi->congested_data, bdi_bits);
	return (bdi->state & bdi_bits);
}

static inline int bdi_read_congested(struct backing_dev_info *bdi)
{
	return bdi_congested(bdi, 1 << BDI_sync_congested);
}

static inline int bdi_write_congested(struct backing_dev_info *bdi)
{
	return bdi_congested(bdi, 1 << BDI_async_congested);
}

static inline int bdi_rw_congested(struct backing_dev_info *bdi)
{
	return bdi_congested(bdi, (1 << BDI_sync_congested) |
				  (1 << BDI_async_congested));
}

enum {
	BLK_RW_ASYNC	= 0,
	BLK_RW_SYNC	= 1,
};

void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
void set_bdi_congested(struct backing_dev_info *bdi, int sync);
long congestion_wait(int sync, long timeout);


static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
{
	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
}

static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
{
	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
}

static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
{
	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
				      BDI_CAP_NO_WRITEBACK));
}

static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
{
	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
}

static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
{
	return bdi == &default_backing_dev_info;
}

static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
{
	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
}

static inline bool mapping_cap_account_dirty(struct address_space *mapping)
{
	return bdi_cap_account_dirty(mapping->backing_dev_info);
}

static inline bool mapping_cap_swap_backed(struct address_space *mapping)
{
	return bdi_cap_swap_backed(mapping->backing_dev_info);
}

static inline int bdi_sched_wait(void *word)
{
	schedule();
	return 0;
}

#endif		/* _LINUX_BACKING_DEV_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* include/linux/backing-dev.h
	3	*
	4	* low-level device information and state which is propagated up through
	5	* to high-level code.
	6	*/
	7
	8	#ifndef _LINUX_BACKING_DEV_H
	9	#define _LINUX_BACKING_DEV_H
	10
b2e8fb6e PZ	11	#include <linux/percpu_counter.h>
b2e8fb6e PZ	12	#include <linux/log2.h>
04fbfdc1	13	#include <linux/proportions.h>
cf0ca9fe	14	#include <linux/kernel.h>
e4ad08fe	15	#include <linux/fs.h>
03ba3782 JA	16	#include <linux/sched.h>
03ba3782 JA	17	#include <linux/writeback.h>
1da177e4 LT	18	#include <asm/atomic.h>
1da177e4 LT	19
3fcfab16	20	struct page;
cf0ca9fe	21	struct device;
76f1418b	22	struct dentry;
3fcfab16	23
1da177e4 LT	24	/*
	25	* Bits in backing_dev_info.state
	26	*/
	27	enum bdi_state {
03ba3782 JA	28	BDI_pending, /* On its way to being activated */
03ba3782 JA	29	BDI_wb_alloc, /* Default embedded wb allocated */
1faa16d2 JA	30	BDI_async_congested, /* The async (write) queue is getting full */
1faa16d2 JA	31	BDI_sync_congested, /* The sync queue is getting full */
500b067c	32	BDI_registered, /* bdi_register() was done */
1da177e4 LT	33	BDI_unused, /* Available bits start here */
	34	};
	35
	36	typedef int (congested_fn)(void *, int);
	37
b2e8fb6e	38	enum bdi_stat_item {
c9e51e41	39	BDI_RECLAIMABLE,
69cb51d1	40	BDI_WRITEBACK,
b2e8fb6e PZ	41	NR_BDI_STAT_ITEMS
	42	};
	43
	44	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	45
03ba3782 JA	46	struct bdi_writeback {
	47	struct list_head list; /* hangs off the bdi */
	48
	49	struct backing_dev_info bdi; / our parent bdi */
	50	unsigned int nr;
	51
	52	unsigned long last_old_flush; /* last old data flush */
	53
	54	struct task_struct task; / writeback task */
	55	struct list_head b_dirty; /* dirty inodes */
	56	struct list_head b_io; /* parked for writeback */
	57	struct list_head b_more_io; /* parked for more writeback */
	58	};
	59
1da177e4	60	struct backing_dev_info {
66f3b8e2	61	struct list_head bdi_list;
cfc4ba53	62	struct rcu_head rcu_head;
1da177e4 LT	63	unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
	64	unsigned long state; /* Always use atomic bitops on this */
	65	unsigned int capabilities; /* Device capabilities */
	66	congested_fn congested_fn; / Function pointer if device is md/dm */
	67	void congested_data; / Pointer to aux data for congested func */
	68	void (unplug_io_fn)(struct backing_dev_info , struct page *);
	69	void *unplug_io_data;
b2e8fb6e	70
d993831f JA	71	char *name;
d993831f JA	72
b2e8fb6e	73	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
04fbfdc1 PZ	74
	75	struct prop_local_percpu completions;
	76	int dirty_exceeded;
cf0ca9fe	77
189d3c4a	78	unsigned int min_ratio;
a42dde04	79	unsigned int max_ratio, max_prop_frac;
189d3c4a	80
03ba3782 JA	81	struct bdi_writeback wb; /* default writeback info for this bdi */
	82	spinlock_t wb_lock; /* protects update side of wb_list */
	83	struct list_head wb_list; /* the flusher threads hanging off this bdi */
	84	unsigned long wb_mask; /* bitmask of registered tasks */
	85	unsigned int wb_cnt; /* number of registered tasks */
76f1418b	86
03ba3782 JA	87	struct list_head work_list;
	88
	89	struct device *dev;
66f3b8e2	90
76f1418b MS	91	#ifdef CONFIG_DEBUG_FS
	92	struct dentry *debug_dir;
	93	struct dentry *debug_stats;
	94	#endif
1da177e4 LT	95	};
1da177e4 LT	96
b2e8fb6e PZ	97	int bdi_init(struct backing_dev_info *bdi);
	98	void bdi_destroy(struct backing_dev_info *bdi);
	99
cf0ca9fe PZ	100	int bdi_register(struct backing_dev_info bdi, struct device parent,
	101	const char *fmt, ...);
	102	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	103	void bdi_unregister(struct backing_dev_info *bdi);
b6e51316	104	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
03ba3782 JA	105	int bdi_writeback_task(struct bdi_writeback *wb);
03ba3782 JA	106	int bdi_has_dirty_io(struct backing_dev_info *bdi);
cf0ca9fe	107
03ba3782	108	extern spinlock_t bdi_lock;
66f3b8e2 JA	109	extern struct list_head bdi_list;
66f3b8e2 JA	110
03ba3782 JA	111	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	112	{
	113	return !list_empty(&wb->b_dirty) \|\|
	114	!list_empty(&wb->b_io) \|\|
	115	!list_empty(&wb->b_more_io);
	116	}
	117
b2e8fb6e PZ	118	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	119	enum bdi_stat_item item, s64 amount)
	120	{
	121	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	122	}
	123
	124	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	125	enum bdi_stat_item item)
	126	{
	127	__add_bdi_stat(bdi, item, 1);
	128	}
	129
	130	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	131	enum bdi_stat_item item)
	132	{
	133	unsigned long flags;
	134
	135	local_irq_save(flags);
	136	__inc_bdi_stat(bdi, item);
	137	local_irq_restore(flags);
	138	}
	139
	140	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	141	enum bdi_stat_item item)
	142	{
	143	__add_bdi_stat(bdi, item, -1);
	144	}
	145
	146	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	147	enum bdi_stat_item item)
	148	{
	149	unsigned long flags;
	150
	151	local_irq_save(flags);
	152	__dec_bdi_stat(bdi, item);
	153	local_irq_restore(flags);
	154	}
	155
	156	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	157	enum bdi_stat_item item)
	158	{
	159	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	160	}
	161
	162	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	163	enum bdi_stat_item item)
	164	{
	165	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	166	}
	167
	168	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	169	enum bdi_stat_item item)
e0bf68dd	170	{
b2e8fb6e PZ	171	s64 sum;
	172	unsigned long flags;
	173
	174	local_irq_save(flags);
	175	sum = __bdi_stat_sum(bdi, item);
	176	local_irq_restore(flags);
	177
	178	return sum;
e0bf68dd PZ	179	}
e0bf68dd PZ	180
dd5656e5 MS	181	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	182
b2e8fb6e PZ	183	/*
	184	* maximal error of a stat counter.
	185	*/
	186	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	187	{
b2e8fb6e PZ	188	#ifdef CONFIG_SMP
	189	return nr_cpu_ids * BDI_STAT_BATCH;
	190	#else
	191	return 1;
	192	#endif
e0bf68dd	193	}
1da177e4	194
189d3c4a	195	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	196	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	197
1da177e4 LT	198	/*
1da177e4 LT	199	* Flags in backing_dev_info::capability
e4ad08fe MS	200	*
	201	* The first three flags control whether dirty pages will contribute to the
	202	* VM's accounting and whether writepages() should be called for dirty pages
	203	* (something that would not, for example, be appropriate for ramfs)
	204	*
	205	* WARNING: these flags are closely related and should not normally be
	206	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	207	* three flags into a single convenience macro.
	208	*
	209	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	210	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	211	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	212	*
	213	* These flags let !MMU mmap() govern direct device mapping vs immediate
	214	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	215	*
	216	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	217	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	218	* BDI_CAP_READ_MAP: Can be mapped for reading
	219	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	220	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	221	*
4f98a2fe RR	222	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	223	*/
e4ad08fe MS	224	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	225	#define BDI_CAP_NO_WRITEBACK 0x00000002
	226	#define BDI_CAP_MAP_COPY 0x00000004
	227	#define BDI_CAP_MAP_DIRECT 0x00000008
	228	#define BDI_CAP_READ_MAP 0x00000010
	229	#define BDI_CAP_WRITE_MAP 0x00000020
	230	#define BDI_CAP_EXEC_MAP 0x00000040
	231	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	232	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	233
1da177e4 LT	234	#define BDI_CAP_VMFLAGS \
	235	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	236
e4ad08fe MS	237	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	238	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	239
1da177e4 LT	240	#if defined(VM_MAYREAD) && \
	241	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	242	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	243	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	244	#error please change backing_dev_info::capabilities flags
	245	#endif
	246
	247	extern struct backing_dev_info default_backing_dev_info;
	248	void default_unplug_io_fn(struct backing_dev_info bdi, struct page page);
	249
1da177e4	250	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	251
	252	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	253	{
	254	if (bdi->congested_fn)
	255	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	256	return (bdi->state & bdi_bits);
	257	}
	258
	259	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	260	{
1faa16d2	261	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	262	}
	263
	264	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	265	{
1faa16d2	266	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	267	}
	268
	269	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	270	{
1faa16d2 JA	271	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	272	(1 << BDI_async_congested));
1da177e4 LT	273	}
1da177e4 LT	274
373c0a7e TM	275	enum {
	276	BLK_RW_ASYNC = 0,
	277	BLK_RW_SYNC = 1,
	278	};
	279
8aa7e847 JA	280	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	281	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	282	long congestion_wait(int sync, long timeout);
3fcfab16	283
1da177e4	284
e4ad08fe MS	285	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	286	{
	287	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	288	}
	289
	290	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	291	{
	292	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	293	}
1da177e4	294
e4ad08fe MS	295	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	296	{
	297	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	298	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	299	BDI_CAP_NO_WRITEBACK));
	300	}
1da177e4	301
4f98a2fe RR	302	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	303	{
	304	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	305	}
	306
03ba3782 JA	307	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	308	{
	309	return bdi == &default_backing_dev_info;
	310	}
	311
e4ad08fe MS	312	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	313	{
	314	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	315	}
1da177e4	316
e4ad08fe MS	317	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	318	{
	319	return bdi_cap_account_dirty(mapping->backing_dev_info);
	320	}
1da177e4	321
4f98a2fe RR	322	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	323	{
	324	return bdi_cap_swap_backed(mapping->backing_dev_info);
	325	}
	326
03ba3782 JA	327	static inline int bdi_sched_wait(void *word)
	328	{
	329	schedule();
	330	return 0;
	331	}
	332
1da177e4	333	#endif /* _LINUX_BACKING_DEV_H */