[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/flex_proportions.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/writeback.h>
#include <linux/atomic.h>
#include <linux/sysctl.h>
#include <linux/workqueue.h>

struct page;
struct device;
struct dentry;

/*
 * Bits in backing_dev_info.state
 */
enum bdi_state {
	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_writeback_running,	/* Writeback is in progress */
};

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

enum bdi_stat_item {
	BDI_RECLAIMABLE,
	BDI_WRITEBACK,
	BDI_DIRTIED,
	BDI_WRITTEN,
	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 long last_old_flush;	/* last old data flush */

	struct delayed_work dwork;	/* work item used for writeback */
	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 */
	spinlock_t list_lock;		/* protects the b_* lists */
};

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 */

	char *name;

	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];

	unsigned long bw_time_stamp;	/* last time write bw is updated */
	unsigned long dirtied_stamp;
	unsigned long written_stamp;	/* pages written at bw_time_stamp */
	unsigned long write_bandwidth;	/* the estimated write bandwidth */
	unsigned long avg_write_bandwidth; /* further smoothed write bw */

	/*
	 * The base dirty throttle rate, re-calculated on every 200ms.
	 * All the bdi tasks' dirty rate will be curbed under it.
	 * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
	 * in small steps and is much more smooth/stable than the latter.
	 */
	unsigned long dirty_ratelimit;
	unsigned long balanced_dirty_ratelimit;

	struct fprop_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 & wb.dwork scheduling */

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

__printf(3, 4)
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 __must_check bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
			enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
void bdi_writeback_workfn(struct work_struct *work);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);

extern spinlock_t bdi_lock;
extern struct list_head bdi_list;

extern struct workqueue_struct *bdi_wq;

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.
 *
 * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
 */
#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_STABLE_WRITES	0x00000200
#define BDI_CAP_STRICTLIMIT	0x00000400

#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;

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);
long wait_iff_congested(struct zone *zone, int sync, long timeout);
int pdflush_proc_obsolete(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp, loff_t *ppos);

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

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 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
	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
	11	#include <linux/percpu_counter.h>
	12	#include <linux/log2.h>
	13	#include <linux/flex_proportions.h>
	14	#include <linux/kernel.h>
	15	#include <linux/fs.h>
	16	#include <linux/sched.h>
	17	#include <linux/timer.h>
	18	#include <linux/writeback.h>
	19	#include <linux/atomic.h>
	20	#include <linux/sysctl.h>
	21	#include <linux/workqueue.h>
	22
	23	struct page;
	24	struct device;
	25	struct dentry;
	26
	27	/*
	28	* Bits in backing_dev_info.state
	29	*/
	30	enum bdi_state {
	31	BDI_async_congested, /* The async (write) queue is getting full */
	32	BDI_sync_congested, /* The sync queue is getting full */
	33	BDI_registered, /* bdi_register() was done */
	34	BDI_writeback_running, /* Writeback is in progress */
	35	};
	36
	37	typedef int (congested_fn)(void *, int);
	38
	39	enum bdi_stat_item {
	40	BDI_RECLAIMABLE,
	41	BDI_WRITEBACK,
	42	BDI_DIRTIED,
	43	BDI_WRITTEN,
	44	NR_BDI_STAT_ITEMS
	45	};
	46
	47	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	48
	49	struct bdi_writeback {
	50	struct backing_dev_info bdi; / our parent bdi */
	51
	52	unsigned long last_old_flush; /* last old data flush */
	53
	54	struct delayed_work dwork; /* work item used for writeback */
	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	spinlock_t list_lock; /* protects the b_* lists */
	59	};
	60
	61	struct backing_dev_info {
	62	struct list_head bdi_list;
	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
	69	char *name;
	70
	71	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
	72
	73	unsigned long bw_time_stamp; /* last time write bw is updated */
	74	unsigned long dirtied_stamp;
	75	unsigned long written_stamp; /* pages written at bw_time_stamp */
	76	unsigned long write_bandwidth; /* the estimated write bandwidth */
	77	unsigned long avg_write_bandwidth; /* further smoothed write bw */
	78
	79	/*
	80	* The base dirty throttle rate, re-calculated on every 200ms.
	81	* All the bdi tasks' dirty rate will be curbed under it.
	82	* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
	83	* in small steps and is much more smooth/stable than the latter.
	84	*/
	85	unsigned long dirty_ratelimit;
	86	unsigned long balanced_dirty_ratelimit;
	87
	88	struct fprop_local_percpu completions;
	89	int dirty_exceeded;
	90
	91	unsigned int min_ratio;
	92	unsigned int max_ratio, max_prop_frac;
	93
	94	struct bdi_writeback wb; /* default writeback info for this bdi */
	95	spinlock_t wb_lock; /* protects work_list & wb.dwork scheduling */
	96
	97	struct list_head work_list;
	98
	99	struct device *dev;
	100
	101	struct timer_list laptop_mode_wb_timer;
	102
	103	#ifdef CONFIG_DEBUG_FS
	104	struct dentry *debug_dir;
	105	struct dentry *debug_stats;
	106	#endif
	107	};
	108
	109	int __must_check bdi_init(struct backing_dev_info *bdi);
	110	void bdi_destroy(struct backing_dev_info *bdi);
	111
	112	__printf(3, 4)
	113	int bdi_register(struct backing_dev_info bdi, struct device parent,
	114	const char *fmt, ...);
	115	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	116	void bdi_unregister(struct backing_dev_info *bdi);
	117	int __must_check bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
	118	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
	119	enum wb_reason reason);
	120	void bdi_start_background_writeback(struct backing_dev_info *bdi);
	121	void bdi_writeback_workfn(struct work_struct *work);
	122	int bdi_has_dirty_io(struct backing_dev_info *bdi);
	123	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
	124
	125	extern spinlock_t bdi_lock;
	126	extern struct list_head bdi_list;
	127
	128	extern struct workqueue_struct *bdi_wq;
	129
	130	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	131	{
	132	return !list_empty(&wb->b_dirty) \|\|
	133	!list_empty(&wb->b_io) \|\|
	134	!list_empty(&wb->b_more_io);
	135	}
	136
	137	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	138	enum bdi_stat_item item, s64 amount)
	139	{
	140	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	141	}
	142
	143	static inline void __inc_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 inc_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	__inc_bdi_stat(bdi, item);
	156	local_irq_restore(flags);
	157	}
	158
	159	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	160	enum bdi_stat_item item)
	161	{
	162	__add_bdi_stat(bdi, item, -1);
	163	}
	164
	165	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	166	enum bdi_stat_item item)
	167	{
	168	unsigned long flags;
	169
	170	local_irq_save(flags);
	171	__dec_bdi_stat(bdi, item);
	172	local_irq_restore(flags);
	173	}
	174
	175	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	176	enum bdi_stat_item item)
	177	{
	178	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	179	}
	180
	181	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	182	enum bdi_stat_item item)
	183	{
	184	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	185	}
	186
	187	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	188	enum bdi_stat_item item)
	189	{
	190	s64 sum;
	191	unsigned long flags;
	192
	193	local_irq_save(flags);
	194	sum = __bdi_stat_sum(bdi, item);
	195	local_irq_restore(flags);
	196
	197	return sum;
	198	}
	199
	200	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
	201
	202	/*
	203	* maximal error of a stat counter.
	204	*/
	205	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
	206	{
	207	#ifdef CONFIG_SMP
	208	return nr_cpu_ids * BDI_STAT_BATCH;
	209	#else
	210	return 1;
	211	#endif
	212	}
	213
	214	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
	215	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
	216
	217	/*
	218	* Flags in backing_dev_info::capability
	219	*
	220	* The first three flags control whether dirty pages will contribute to the
	221	* VM's accounting and whether writepages() should be called for dirty pages
	222	* (something that would not, for example, be appropriate for ramfs)
	223	*
	224	* WARNING: these flags are closely related and should not normally be
	225	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	226	* three flags into a single convenience macro.
	227	*
	228	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	229	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	230	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	231	*
	232	* These flags let !MMU mmap() govern direct device mapping vs immediate
	233	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	234	*
	235	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	236	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	237	* BDI_CAP_READ_MAP: Can be mapped for reading
	238	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	239	* BDI_CAP_EXEC_MAP: Can be mapped for execution
	240	*
	241	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
	242	*
	243	* BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold.
	244	*/
	245	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	246	#define BDI_CAP_NO_WRITEBACK 0x00000002
	247	#define BDI_CAP_MAP_COPY 0x00000004
	248	#define BDI_CAP_MAP_DIRECT 0x00000008
	249	#define BDI_CAP_READ_MAP 0x00000010
	250	#define BDI_CAP_WRITE_MAP 0x00000020
	251	#define BDI_CAP_EXEC_MAP 0x00000040
	252	#define BDI_CAP_NO_ACCT_WB 0x00000080
	253	#define BDI_CAP_SWAP_BACKED 0x00000100
	254	#define BDI_CAP_STABLE_WRITES 0x00000200
	255	#define BDI_CAP_STRICTLIMIT 0x00000400
	256
	257	#define BDI_CAP_VMFLAGS \
	258	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	259
	260	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	261	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	262
	263	#if defined(VM_MAYREAD) && \
	264	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	265	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	266	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	267	#error please change backing_dev_info::capabilities flags
	268	#endif
	269
	270	extern struct backing_dev_info default_backing_dev_info;
	271	extern struct backing_dev_info noop_backing_dev_info;
	272
	273	int writeback_in_progress(struct backing_dev_info *bdi);
	274
	275	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	276	{
	277	if (bdi->congested_fn)
	278	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	279	return (bdi->state & bdi_bits);
	280	}
	281
	282	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	283	{
	284	return bdi_congested(bdi, 1 << BDI_sync_congested);
	285	}
	286
	287	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	288	{
	289	return bdi_congested(bdi, 1 << BDI_async_congested);
	290	}
	291
	292	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	293	{
	294	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
	295	(1 << BDI_async_congested));
	296	}
	297
	298	enum {
	299	BLK_RW_ASYNC = 0,
	300	BLK_RW_SYNC = 1,
	301	};
	302
	303	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	304	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	305	long congestion_wait(int sync, long timeout);
	306	long wait_iff_congested(struct zone *zone, int sync, long timeout);
	307	int pdflush_proc_obsolete(struct ctl_table *table, int write,
	308	void __user buffer, size_t lenp, loff_t *ppos);
	309
	310	static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
	311	{
	312	return bdi->capabilities & BDI_CAP_STABLE_WRITES;
	313	}
	314
	315	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	316	{
	317	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	318	}
	319
	320	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	321	{
	322	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	323	}
	324
	325	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	326	{
	327	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	328	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	329	BDI_CAP_NO_WRITEBACK));
	330	}
	331
	332	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	333	{
	334	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	335	}
	336
	337	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	338	{
	339	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	340	}
	341
	342	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	343	{
	344	return bdi_cap_account_dirty(mapping->backing_dev_info);
	345	}
	346
	347	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	348	{
	349	return bdi_cap_swap_backed(mapping->backing_dev_info);
	350	}
	351
	352	static inline int bdi_sched_wait(void *word)
	353	{
	354	schedule();
	355	return 0;
	356	}
	357
	358	#endif /* _LINUX_BACKING_DEV_H */