[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);
int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,
				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;
extern struct backing_dev_info noop_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;
}

static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
				       struct page *page)
{
	if (bdi && bdi->unplug_io_fn)
		bdi->unplug_io_fn(bdi, page);
}

static inline void blk_run_address_space(struct address_space *mapping)
{
	if (mapping)
		blk_run_backing_dev(mapping->backing_dev_info, NULL);
}

#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);
c3c53206	104	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
a72bfd4d JA	105	void bdi_start_writeback(struct backing_dev_info bdi, struct super_block sb,
a72bfd4d JA	106	long nr_pages);
03ba3782 JA	107	int bdi_writeback_task(struct bdi_writeback *wb);
03ba3782 JA	108	int bdi_has_dirty_io(struct backing_dev_info *bdi);
cf0ca9fe	109
03ba3782	110	extern spinlock_t bdi_lock;
66f3b8e2 JA	111	extern struct list_head bdi_list;
66f3b8e2 JA	112
03ba3782 JA	113	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	114	{
	115	return !list_empty(&wb->b_dirty) \|\|
	116	!list_empty(&wb->b_io) \|\|
	117	!list_empty(&wb->b_more_io);
	118	}
	119
b2e8fb6e PZ	120	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	121	enum bdi_stat_item item, s64 amount)
	122	{
	123	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	124	}
	125
	126	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	127	enum bdi_stat_item item)
	128	{
	129	__add_bdi_stat(bdi, item, 1);
	130	}
	131
	132	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	133	enum bdi_stat_item item)
	134	{
	135	unsigned long flags;
	136
	137	local_irq_save(flags);
	138	__inc_bdi_stat(bdi, item);
	139	local_irq_restore(flags);
	140	}
	141
	142	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	143	enum bdi_stat_item item)
	144	{
	145	__add_bdi_stat(bdi, item, -1);
	146	}
	147
	148	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	149	enum bdi_stat_item item)
	150	{
	151	unsigned long flags;
	152
	153	local_irq_save(flags);
	154	__dec_bdi_stat(bdi, item);
	155	local_irq_restore(flags);
	156	}
	157
	158	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	159	enum bdi_stat_item item)
	160	{
	161	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	162	}
	163
	164	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	165	enum bdi_stat_item item)
	166	{
	167	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	168	}
	169
	170	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	171	enum bdi_stat_item item)
e0bf68dd	172	{
b2e8fb6e PZ	173	s64 sum;
	174	unsigned long flags;
	175
	176	local_irq_save(flags);
	177	sum = __bdi_stat_sum(bdi, item);
	178	local_irq_restore(flags);
	179
	180	return sum;
e0bf68dd PZ	181	}
e0bf68dd PZ	182
dd5656e5 MS	183	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	184
b2e8fb6e PZ	185	/*
	186	* maximal error of a stat counter.
	187	*/
	188	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	189	{
b2e8fb6e PZ	190	#ifdef CONFIG_SMP
	191	return nr_cpu_ids * BDI_STAT_BATCH;
	192	#else
	193	return 1;
	194	#endif
e0bf68dd	195	}
1da177e4	196
189d3c4a	197	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	198	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	199
1da177e4 LT	200	/*
1da177e4 LT	201	* Flags in backing_dev_info::capability
e4ad08fe MS	202	*
	203	* The first three flags control whether dirty pages will contribute to the
	204	* VM's accounting and whether writepages() should be called for dirty pages
	205	* (something that would not, for example, be appropriate for ramfs)
	206	*
	207	* WARNING: these flags are closely related and should not normally be
	208	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	209	* three flags into a single convenience macro.
	210	*
	211	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	212	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	213	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	214	*
	215	* These flags let !MMU mmap() govern direct device mapping vs immediate
	216	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	217	*
	218	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	219	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	220	* BDI_CAP_READ_MAP: Can be mapped for reading
	221	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	222	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	223	*
4f98a2fe RR	224	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	225	*/
e4ad08fe MS	226	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	227	#define BDI_CAP_NO_WRITEBACK 0x00000002
	228	#define BDI_CAP_MAP_COPY 0x00000004
	229	#define BDI_CAP_MAP_DIRECT 0x00000008
	230	#define BDI_CAP_READ_MAP 0x00000010
	231	#define BDI_CAP_WRITE_MAP 0x00000020
	232	#define BDI_CAP_EXEC_MAP 0x00000040
	233	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	234	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	235
1da177e4 LT	236	#define BDI_CAP_VMFLAGS \
	237	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	238
e4ad08fe MS	239	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	240	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	241
1da177e4 LT	242	#if defined(VM_MAYREAD) && \
	243	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	244	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	245	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	246	#error please change backing_dev_info::capabilities flags
	247	#endif
	248
	249	extern struct backing_dev_info default_backing_dev_info;
5129a469	250	extern struct backing_dev_info noop_backing_dev_info;
1da177e4 LT	251	void default_unplug_io_fn(struct backing_dev_info bdi, struct page page);
1da177e4 LT	252
1da177e4	253	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	254
	255	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	256	{
	257	if (bdi->congested_fn)
	258	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	259	return (bdi->state & bdi_bits);
	260	}
	261
	262	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	263	{
1faa16d2	264	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	265	}
	266
	267	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	268	{
1faa16d2	269	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	270	}
	271
	272	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	273	{
1faa16d2 JA	274	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	275	(1 << BDI_async_congested));
1da177e4 LT	276	}
1da177e4 LT	277
373c0a7e TM	278	enum {
	279	BLK_RW_ASYNC = 0,
	280	BLK_RW_SYNC = 1,
	281	};
	282
8aa7e847 JA	283	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	284	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	285	long congestion_wait(int sync, long timeout);
3fcfab16	286
1da177e4	287
e4ad08fe MS	288	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	289	{
	290	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	291	}
	292
	293	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	294	{
	295	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	296	}
1da177e4	297
e4ad08fe MS	298	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	299	{
	300	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	301	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	302	BDI_CAP_NO_WRITEBACK));
	303	}
1da177e4	304
4f98a2fe RR	305	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	306	{
	307	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	308	}
	309
03ba3782 JA	310	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	311	{
	312	return bdi == &default_backing_dev_info;
	313	}
	314
e4ad08fe MS	315	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	316	{
	317	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	318	}
1da177e4	319
e4ad08fe MS	320	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	321	{
	322	return bdi_cap_account_dirty(mapping->backing_dev_info);
	323	}
1da177e4	324
4f98a2fe RR	325	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	326	{
	327	return bdi_cap_swap_backed(mapping->backing_dev_info);
	328	}
	329
03ba3782 JA	330	static inline int bdi_sched_wait(void *word)
	331	{
	332	schedule();
	333	return 0;
	334	}
	335
b9d128f1 JA	336	static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
	337	struct page *page)
	338	{
	339	if (bdi && bdi->unplug_io_fn)
	340	bdi->unplug_io_fn(bdi, page);
	341	}
	342
	343	static inline void blk_run_address_space(struct address_space *mapping)
	344	{
	345	if (mapping)
	346	blk_run_backing_dev(mapping->backing_dev_info, NULL);
	347	}
	348
1da177e4	349	#endif /* _LINUX_BACKING_DEV_H */