[net-next-2.6.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/timer.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 backing_dev_info *bdi;	/* our parent bdi */
	unsigned int nr;

	unsigned long last_old_flush;	/* last old data flush */
	unsigned long last_active;	/* last time bdi thread was active */

	struct task_struct *task;	/* writeback thread */
	struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */
	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;
	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 work_list */

	struct list_head work_list;

	struct device *dev;

	struct timer_list laptop_mode_wb_timer;

#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, long nr_pages);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
int bdi_writeback_thread(void *data);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
void bdi_arm_supers_timer(void);
void bdi_wakeup_thread_delayed(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	16	#include <linux/sched.h>
31373d09	17	#include <linux/timer.h>
03ba3782	18	#include <linux/writeback.h>
1da177e4 LT	19	#include <asm/atomic.h>
1da177e4 LT	20
3fcfab16	21	struct page;
cf0ca9fe	22	struct device;
76f1418b	23	struct dentry;
3fcfab16	24
1da177e4 LT	25	/*
	26	* Bits in backing_dev_info.state
	27	*/
	28	enum bdi_state {
03ba3782 JA	29	BDI_pending, /* On its way to being activated */
03ba3782 JA	30	BDI_wb_alloc, /* Default embedded wb allocated */
1faa16d2 JA	31	BDI_async_congested, /* The async (write) queue is getting full */
1faa16d2 JA	32	BDI_sync_congested, /* The sync queue is getting full */
500b067c	33	BDI_registered, /* bdi_register() was done */
1da177e4 LT	34	BDI_unused, /* Available bits start here */
	35	};
	36
	37	typedef int (congested_fn)(void *, int);
	38
b2e8fb6e	39	enum bdi_stat_item {
c9e51e41	40	BDI_RECLAIMABLE,
69cb51d1	41	BDI_WRITEBACK,
b2e8fb6e PZ	42	NR_BDI_STAT_ITEMS
	43	};
	44
	45	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	46
03ba3782	47	struct bdi_writeback {
ecd58403	48	struct backing_dev_info bdi; / our parent bdi */
03ba3782 JA	49	unsigned int nr;
03ba3782 JA	50
ecd58403 AB	51	unsigned long last_old_flush; /* last old data flush */
ecd58403 AB	52	unsigned long last_active; /* last time bdi thread was active */
03ba3782	53
ecd58403	54	struct task_struct task; / writeback thread */
6467716a	55	struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */
ecd58403 AB	56	struct list_head b_dirty; /* dirty inodes */
	57	struct list_head b_io; /* parked for writeback */
	58	struct list_head b_more_io; /* parked for more writeback */
03ba3782 JA	59	};
03ba3782 JA	60
1da177e4	61	struct backing_dev_info {
66f3b8e2	62	struct list_head bdi_list;
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	81	struct bdi_writeback wb; /* default writeback info for this bdi */
c1955ce3	82	spinlock_t wb_lock; /* protects work_list */
76f1418b	83
03ba3782 JA	84	struct list_head work_list;
	85
	86	struct device *dev;
66f3b8e2	87
31373d09 MG	88	struct timer_list laptop_mode_wb_timer;
31373d09 MG	89
76f1418b MS	90	#ifdef CONFIG_DEBUG_FS
	91	struct dentry *debug_dir;
	92	struct dentry *debug_stats;
	93	#endif
1da177e4 LT	94	};
1da177e4 LT	95
b2e8fb6e PZ	96	int bdi_init(struct backing_dev_info *bdi);
	97	void bdi_destroy(struct backing_dev_info *bdi);
	98
cf0ca9fe PZ	99	int bdi_register(struct backing_dev_info bdi, struct device parent,
	100	const char *fmt, ...);
	101	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	102	void bdi_unregister(struct backing_dev_info *bdi);
c3c53206	103	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
c5444198 CH	104	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
c5444198 CH	105	void bdi_start_background_writeback(struct backing_dev_info *bdi);
08243900	106	int bdi_writeback_thread(void *data);
03ba3782	107	int bdi_has_dirty_io(struct backing_dev_info *bdi);
6423104b	108	void bdi_arm_supers_timer(void);
6467716a	109	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
cf0ca9fe	110
03ba3782	111	extern spinlock_t bdi_lock;
66f3b8e2 JA	112	extern struct list_head bdi_list;
66f3b8e2 JA	113
03ba3782 JA	114	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	115	{
	116	return !list_empty(&wb->b_dirty) \|\|
	117	!list_empty(&wb->b_io) \|\|
	118	!list_empty(&wb->b_more_io);
	119	}
	120
b2e8fb6e PZ	121	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	122	enum bdi_stat_item item, s64 amount)
	123	{
	124	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	125	}
	126
	127	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	128	enum bdi_stat_item item)
	129	{
	130	__add_bdi_stat(bdi, item, 1);
	131	}
	132
	133	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	134	enum bdi_stat_item item)
	135	{
	136	unsigned long flags;
	137
	138	local_irq_save(flags);
	139	__inc_bdi_stat(bdi, item);
	140	local_irq_restore(flags);
	141	}
	142
	143	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	144	enum bdi_stat_item item)
	145	{
	146	__add_bdi_stat(bdi, item, -1);
	147	}
	148
	149	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	150	enum bdi_stat_item item)
	151	{
	152	unsigned long flags;
	153
	154	local_irq_save(flags);
	155	__dec_bdi_stat(bdi, item);
	156	local_irq_restore(flags);
	157	}
	158
	159	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	160	enum bdi_stat_item item)
	161	{
	162	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	163	}
	164
	165	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	166	enum bdi_stat_item item)
	167	{
	168	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	169	}
	170
	171	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	172	enum bdi_stat_item item)
e0bf68dd	173	{
b2e8fb6e PZ	174	s64 sum;
	175	unsigned long flags;
	176
	177	local_irq_save(flags);
	178	sum = __bdi_stat_sum(bdi, item);
	179	local_irq_restore(flags);
	180
	181	return sum;
e0bf68dd PZ	182	}
e0bf68dd PZ	183
dd5656e5 MS	184	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	185
b2e8fb6e PZ	186	/*
	187	* maximal error of a stat counter.
	188	*/
	189	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	190	{
b2e8fb6e PZ	191	#ifdef CONFIG_SMP
	192	return nr_cpu_ids * BDI_STAT_BATCH;
	193	#else
	194	return 1;
	195	#endif
e0bf68dd	196	}
1da177e4	197
189d3c4a	198	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	199	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	200
1da177e4 LT	201	/*
1da177e4 LT	202	* Flags in backing_dev_info::capability
e4ad08fe MS	203	*
	204	* The first three flags control whether dirty pages will contribute to the
	205	* VM's accounting and whether writepages() should be called for dirty pages
	206	* (something that would not, for example, be appropriate for ramfs)
	207	*
	208	* WARNING: these flags are closely related and should not normally be
	209	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	210	* three flags into a single convenience macro.
	211	*
	212	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	213	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	214	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	215	*
	216	* These flags let !MMU mmap() govern direct device mapping vs immediate
	217	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	218	*
	219	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	220	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	221	* BDI_CAP_READ_MAP: Can be mapped for reading
	222	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	223	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	224	*
4f98a2fe RR	225	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	226	*/
e4ad08fe MS	227	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	228	#define BDI_CAP_NO_WRITEBACK 0x00000002
	229	#define BDI_CAP_MAP_COPY 0x00000004
	230	#define BDI_CAP_MAP_DIRECT 0x00000008
	231	#define BDI_CAP_READ_MAP 0x00000010
	232	#define BDI_CAP_WRITE_MAP 0x00000020
	233	#define BDI_CAP_EXEC_MAP 0x00000040
	234	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	235	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	236
1da177e4 LT	237	#define BDI_CAP_VMFLAGS \
	238	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	239
e4ad08fe MS	240	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	241	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	242
1da177e4 LT	243	#if defined(VM_MAYREAD) && \
	244	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	245	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	246	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	247	#error please change backing_dev_info::capabilities flags
	248	#endif
	249
	250	extern struct backing_dev_info default_backing_dev_info;
5129a469	251	extern struct backing_dev_info noop_backing_dev_info;
1da177e4 LT	252	void default_unplug_io_fn(struct backing_dev_info bdi, struct page page);
1da177e4 LT	253
1da177e4	254	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	255
	256	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	257	{
	258	if (bdi->congested_fn)
	259	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	260	return (bdi->state & bdi_bits);
	261	}
	262
	263	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	264	{
1faa16d2	265	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	266	}
	267
	268	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	269	{
1faa16d2	270	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	271	}
	272
	273	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	274	{
1faa16d2 JA	275	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	276	(1 << BDI_async_congested));
1da177e4 LT	277	}
1da177e4 LT	278
373c0a7e TM	279	enum {
	280	BLK_RW_ASYNC = 0,
	281	BLK_RW_SYNC = 1,
	282	};
	283
8aa7e847 JA	284	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	285	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	286	long congestion_wait(int sync, long timeout);
3fcfab16	287
1da177e4	288
e4ad08fe MS	289	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	290	{
	291	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	292	}
	293
	294	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	295	{
	296	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	297	}
1da177e4	298
e4ad08fe MS	299	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	300	{
	301	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	302	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	303	BDI_CAP_NO_WRITEBACK));
	304	}
1da177e4	305
4f98a2fe RR	306	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	307	{
	308	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	309	}
	310
03ba3782 JA	311	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	312	{
	313	return bdi == &default_backing_dev_info;
	314	}
	315
e4ad08fe MS	316	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	317	{
	318	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	319	}
1da177e4	320
e4ad08fe MS	321	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	322	{
	323	return bdi_cap_account_dirty(mapping->backing_dev_info);
	324	}
1da177e4	325
4f98a2fe RR	326	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	327	{
	328	return bdi_cap_swap_backed(mapping->backing_dev_info);
	329	}
	330
03ba3782 JA	331	static inline int bdi_sched_wait(void *word)
	332	{
	333	schedule();
	334	return 0;
	335	}
	336
b9d128f1 JA	337	static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
	338	struct page *page)
	339	{
	340	if (bdi && bdi->unplug_io_fn)
	341	bdi->unplug_io_fn(bdi, page);
	342	}
	343
	344	static inline void blk_run_address_space(struct address_space *mapping)
	345	{
	346	if (mapping)
	347	blk_run_backing_dev(mapping->backing_dev_info, NULL);
	348	}
	349
1da177e4	350	#endif /* _LINUX_BACKING_DEV_H */