[mirror_ubuntu-artful-kernel.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_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_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 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 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>
eb608e3a	13	#include <linux/flex_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>
60063497	19	#include <linux/atomic.h>
3965c9ae	20	#include <linux/sysctl.h>
839a8e86	21	#include <linux/workqueue.h>
1da177e4	22
3fcfab16	23	struct page;
cf0ca9fe	24	struct device;
76f1418b	25	struct dentry;
3fcfab16	26
1da177e4 LT	27	/*
	28	* Bits in backing_dev_info.state
	29	*/
	30	enum bdi_state {
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 */
81d73a32	34	BDI_writeback_running, /* Writeback is in progress */
1da177e4 LT	35	};
	36
	37	typedef int (congested_fn)(void *, int);
	38
b2e8fb6e	39	enum bdi_stat_item {
c9e51e41	40	BDI_RECLAIMABLE,
69cb51d1	41	BDI_WRITEBACK,
c8e28ce0	42	BDI_DIRTIED,
f7d2b1ec	43	BDI_WRITTEN,
b2e8fb6e PZ	44	NR_BDI_STAT_ITEMS
	45	};
	46
	47	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	48
03ba3782	49	struct bdi_writeback {
ecd58403	50	struct backing_dev_info bdi; / our parent bdi */
03ba3782	51
ecd58403	52	unsigned long last_old_flush; /* last old data flush */
03ba3782	53
839a8e86	54	struct delayed_work dwork; /* work item used for writeback */
ecd58403 AB	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 */
f758eeab	58	spinlock_t list_lock; /* protects the b_* lists */
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 */
b2e8fb6e	68
d993831f JA	69	char *name;
d993831f JA	70
b2e8fb6e	71	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
04fbfdc1	72
e98be2d5	73	unsigned long bw_time_stamp; /* last time write bw is updated */
be3ffa27	74	unsigned long dirtied_stamp;
e98be2d5 WF	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
be3ffa27 WF	79	/*
	80	* The base dirty throttle rate, re-calculated on every 200ms.
	81	* All the bdi tasks' dirty rate will be curbed under it.
7381131c WF	82	* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
7381131c WF	83	* in small steps and is much more smooth/stable than the latter.
be3ffa27 WF	84	*/
be3ffa27 WF	85	unsigned long dirty_ratelimit;
7381131c	86	unsigned long balanced_dirty_ratelimit;
be3ffa27	87
eb608e3a	88	struct fprop_local_percpu completions;
04fbfdc1	89	int dirty_exceeded;
cf0ca9fe	90
189d3c4a	91	unsigned int min_ratio;
a42dde04	92	unsigned int max_ratio, max_prop_frac;
189d3c4a	93
03ba3782	94	struct bdi_writeback wb; /* default writeback info for this bdi */
5acda9d1	95	spinlock_t wb_lock; /* protects work_list & wb.dwork scheduling */
76f1418b	96
03ba3782 JA	97	struct list_head work_list;
	98
	99	struct device *dev;
66f3b8e2	100
31373d09 MG	101	struct timer_list laptop_mode_wb_timer;
31373d09 MG	102
76f1418b MS	103	#ifdef CONFIG_DEBUG_FS
	104	struct dentry *debug_dir;
	105	struct dentry *debug_stats;
	106	#endif
1da177e4 LT	107	};
1da177e4 LT	108
8077c0d9	109	int __must_check bdi_init(struct backing_dev_info *bdi);
b2e8fb6e PZ	110	void bdi_destroy(struct backing_dev_info *bdi);
b2e8fb6e PZ	111
d2cc4dde	112	__printf(3, 4)
cf0ca9fe PZ	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);
8077c0d9	117	int __must_check bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
0e175a18 CW	118	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
0e175a18 CW	119	enum wb_reason reason);
c5444198	120	void bdi_start_background_writeback(struct backing_dev_info *bdi);
839a8e86	121	void bdi_writeback_workfn(struct work_struct *work);
03ba3782	122	int bdi_has_dirty_io(struct backing_dev_info *bdi);
6467716a	123	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
cf0ca9fe	124
03ba3782	125	extern spinlock_t bdi_lock;
66f3b8e2 JA	126	extern struct list_head bdi_list;
66f3b8e2 JA	127
839a8e86 TH	128	extern struct workqueue_struct *bdi_wq;
839a8e86 TH	129
03ba3782 JA	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
b2e8fb6e PZ	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)
e0bf68dd	189	{
b2e8fb6e PZ	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;
e0bf68dd PZ	198	}
e0bf68dd PZ	199
dd5656e5 MS	200	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	201
b2e8fb6e PZ	202	/*
	203	* maximal error of a stat counter.
	204	*/
	205	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	206	{
b2e8fb6e PZ	207	#ifdef CONFIG_SMP
	208	return nr_cpu_ids * BDI_STAT_BATCH;
	209	#else
	210	return 1;
	211	#endif
e0bf68dd	212	}
1da177e4	213
189d3c4a	214	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	215	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	216
1da177e4 LT	217	/*
1da177e4 LT	218	* Flags in backing_dev_info::capability
e4ad08fe MS	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
4f98a2fe	240	*
5a537485	241	* BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold.
1da177e4	242	*/
e4ad08fe MS	243	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	244	#define BDI_CAP_NO_WRITEBACK 0x00000002
	245	#define BDI_CAP_MAP_COPY 0x00000004
	246	#define BDI_CAP_MAP_DIRECT 0x00000008
	247	#define BDI_CAP_READ_MAP 0x00000010
	248	#define BDI_CAP_WRITE_MAP 0x00000020
	249	#define BDI_CAP_EXEC_MAP 0x00000040
	250	#define BDI_CAP_NO_ACCT_WB 0x00000080
7d311cda	251	#define BDI_CAP_STABLE_WRITES 0x00000200
5a537485	252	#define BDI_CAP_STRICTLIMIT 0x00000400
e4ad08fe	253
1da177e4 LT	254	#define BDI_CAP_VMFLAGS \
	255	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	256
e4ad08fe MS	257	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	258	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	259
1da177e4 LT	260	#if defined(VM_MAYREAD) && \
	261	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	262	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	263	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	264	#error please change backing_dev_info::capabilities flags
	265	#endif
	266
	267	extern struct backing_dev_info default_backing_dev_info;
5129a469	268	extern struct backing_dev_info noop_backing_dev_info;
1da177e4	269
1da177e4	270	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	271
	272	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	273	{
	274	if (bdi->congested_fn)
	275	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	276	return (bdi->state & bdi_bits);
	277	}
	278
	279	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	280	{
1faa16d2	281	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	282	}
	283
	284	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	285	{
1faa16d2	286	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	287	}
	288
	289	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	290	{
1faa16d2 JA	291	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	292	(1 << BDI_async_congested));
1da177e4 LT	293	}
1da177e4 LT	294
373c0a7e TM	295	enum {
	296	BLK_RW_ASYNC = 0,
	297	BLK_RW_SYNC = 1,
	298	};
	299
8aa7e847 JA	300	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	301	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	302	long congestion_wait(int sync, long timeout);
0e093d99	303	long wait_iff_congested(struct zone *zone, int sync, long timeout);
3965c9ae WL	304	int pdflush_proc_obsolete(struct ctl_table *table, int write,
3965c9ae WL	305	void __user buffer, size_t lenp, loff_t *ppos);
1da177e4	306
7d311cda DW	307	static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
	308	{
	309	return bdi->capabilities & BDI_CAP_STABLE_WRITES;
	310	}
	311
e4ad08fe MS	312	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	313	{
	314	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	315	}
	316
	317	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	318	{
	319	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	320	}
1da177e4	321
e4ad08fe MS	322	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	323	{
	324	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	325	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	326	BDI_CAP_NO_WRITEBACK));
	327	}
1da177e4	328
e4ad08fe MS	329	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	330	{
	331	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	332	}
1da177e4	333
e4ad08fe MS	334	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	335	{
	336	return bdi_cap_account_dirty(mapping->backing_dev_info);
	337	}
1da177e4	338
03ba3782 JA	339	static inline int bdi_sched_wait(void *word)
	340	{
	341	schedule();
	342	return 0;
	343	}
	344
1da177e4	345	#endif /* _LINUX_BACKING_DEV_H */