[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>

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_writeback_running,	/* Writeback is in progress */
	BDI_unused,		/* Available bits start here */
};

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 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 */
	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 */

	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,
			enum wb_reason reason);
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_wakeup_thread_delayed(struct backing_dev_info *bdi);
void bdi_lock_two(struct bdi_writeback *wb1, struct bdi_writeback *wb2);

extern spinlock_t bdi_lock;
extern struct list_head bdi_list;
extern struct list_head bdi_pending_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;

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_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>
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>
1da177e4	21
3fcfab16	22	struct page;
cf0ca9fe	23	struct device;
76f1418b	24	struct dentry;
3fcfab16	25
1da177e4 LT	26	/*
	27	* Bits in backing_dev_info.state
	28	*/
	29	enum bdi_state {
03ba3782 JA	30	BDI_pending, /* On its way to being activated */
03ba3782 JA	31	BDI_wb_alloc, /* Default embedded wb allocated */
1faa16d2 JA	32	BDI_async_congested, /* The async (write) queue is getting full */
1faa16d2 JA	33	BDI_sync_congested, /* The sync queue is getting full */
500b067c	34	BDI_registered, /* bdi_register() was done */
81d73a32	35	BDI_writeback_running, /* Writeback is in progress */
1da177e4 LT	36	BDI_unused, /* Available bits start here */
	37	};
	38
	39	typedef int (congested_fn)(void *, int);
	40
b2e8fb6e	41	enum bdi_stat_item {
c9e51e41	42	BDI_RECLAIMABLE,
69cb51d1	43	BDI_WRITEBACK,
c8e28ce0	44	BDI_DIRTIED,
f7d2b1ec	45	BDI_WRITTEN,
b2e8fb6e PZ	46	NR_BDI_STAT_ITEMS
	47	};
	48
	49	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	50
03ba3782	51	struct bdi_writeback {
ecd58403	52	struct backing_dev_info bdi; / our parent bdi */
03ba3782 JA	53	unsigned int nr;
03ba3782 JA	54
ecd58403 AB	55	unsigned long last_old_flush; /* last old data flush */
ecd58403 AB	56	unsigned long last_active; /* last time bdi thread was active */
03ba3782	57
ecd58403	58	struct task_struct task; / writeback thread */
6467716a	59	struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */
ecd58403 AB	60	struct list_head b_dirty; /* dirty inodes */
	61	struct list_head b_io; /* parked for writeback */
	62	struct list_head b_more_io; /* parked for more writeback */
f758eeab	63	spinlock_t list_lock; /* protects the b_* lists */
03ba3782 JA	64	};
03ba3782 JA	65
1da177e4	66	struct backing_dev_info {
66f3b8e2	67	struct list_head bdi_list;
1da177e4 LT	68	unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
	69	unsigned long state; /* Always use atomic bitops on this */
	70	unsigned int capabilities; /* Device capabilities */
	71	congested_fn congested_fn; / Function pointer if device is md/dm */
	72	void congested_data; / Pointer to aux data for congested func */
b2e8fb6e	73
d993831f JA	74	char *name;
d993831f JA	75
b2e8fb6e	76	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
04fbfdc1	77
e98be2d5	78	unsigned long bw_time_stamp; /* last time write bw is updated */
be3ffa27	79	unsigned long dirtied_stamp;
e98be2d5 WF	80	unsigned long written_stamp; /* pages written at bw_time_stamp */
	81	unsigned long write_bandwidth; /* the estimated write bandwidth */
	82	unsigned long avg_write_bandwidth; /* further smoothed write bw */
	83
be3ffa27 WF	84	/*
	85	* The base dirty throttle rate, re-calculated on every 200ms.
	86	* All the bdi tasks' dirty rate will be curbed under it.
7381131c WF	87	* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
7381131c WF	88	* in small steps and is much more smooth/stable than the latter.
be3ffa27 WF	89	*/
be3ffa27 WF	90	unsigned long dirty_ratelimit;
7381131c	91	unsigned long balanced_dirty_ratelimit;
be3ffa27	92
eb608e3a	93	struct fprop_local_percpu completions;
04fbfdc1	94	int dirty_exceeded;
cf0ca9fe	95
189d3c4a	96	unsigned int min_ratio;
a42dde04	97	unsigned int max_ratio, max_prop_frac;
189d3c4a	98
03ba3782	99	struct bdi_writeback wb; /* default writeback info for this bdi */
c1955ce3	100	spinlock_t wb_lock; /* protects work_list */
76f1418b	101
03ba3782 JA	102	struct list_head work_list;
	103
	104	struct device *dev;
66f3b8e2	105
31373d09 MG	106	struct timer_list laptop_mode_wb_timer;
31373d09 MG	107
76f1418b MS	108	#ifdef CONFIG_DEBUG_FS
	109	struct dentry *debug_dir;
	110	struct dentry *debug_stats;
	111	#endif
1da177e4 LT	112	};
1da177e4 LT	113
b2e8fb6e PZ	114	int bdi_init(struct backing_dev_info *bdi);
	115	void bdi_destroy(struct backing_dev_info *bdi);
	116
cf0ca9fe PZ	117	int bdi_register(struct backing_dev_info bdi, struct device parent,
	118	const char *fmt, ...);
	119	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	120	void bdi_unregister(struct backing_dev_info *bdi);
c3c53206	121	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
0e175a18 CW	122	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
0e175a18 CW	123	enum wb_reason reason);
c5444198	124	void bdi_start_background_writeback(struct backing_dev_info *bdi);
08243900	125	int bdi_writeback_thread(void *data);
03ba3782	126	int bdi_has_dirty_io(struct backing_dev_info *bdi);
6467716a	127	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
f758eeab	128	void bdi_lock_two(struct bdi_writeback wb1, struct bdi_writeback wb2);
cf0ca9fe	129
03ba3782	130	extern spinlock_t bdi_lock;
66f3b8e2	131	extern struct list_head bdi_list;
92c09c04	132	extern struct list_head bdi_pending_list;
66f3b8e2	133
03ba3782 JA	134	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	135	{
	136	return !list_empty(&wb->b_dirty) \|\|
	137	!list_empty(&wb->b_io) \|\|
	138	!list_empty(&wb->b_more_io);
	139	}
	140
b2e8fb6e PZ	141	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	142	enum bdi_stat_item item, s64 amount)
	143	{
	144	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	145	}
	146
	147	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	148	enum bdi_stat_item item)
	149	{
	150	__add_bdi_stat(bdi, item, 1);
	151	}
	152
	153	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	154	enum bdi_stat_item item)
	155	{
	156	unsigned long flags;
	157
	158	local_irq_save(flags);
	159	__inc_bdi_stat(bdi, item);
	160	local_irq_restore(flags);
	161	}
	162
	163	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	164	enum bdi_stat_item item)
	165	{
	166	__add_bdi_stat(bdi, item, -1);
	167	}
	168
	169	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	170	enum bdi_stat_item item)
	171	{
	172	unsigned long flags;
	173
	174	local_irq_save(flags);
	175	__dec_bdi_stat(bdi, item);
	176	local_irq_restore(flags);
	177	}
	178
	179	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	180	enum bdi_stat_item item)
	181	{
	182	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	183	}
	184
	185	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	186	enum bdi_stat_item item)
	187	{
	188	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	189	}
	190
	191	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	192	enum bdi_stat_item item)
e0bf68dd	193	{
b2e8fb6e PZ	194	s64 sum;
	195	unsigned long flags;
	196
	197	local_irq_save(flags);
	198	sum = __bdi_stat_sum(bdi, item);
	199	local_irq_restore(flags);
	200
	201	return sum;
e0bf68dd PZ	202	}
e0bf68dd PZ	203
dd5656e5 MS	204	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	205
b2e8fb6e PZ	206	/*
	207	* maximal error of a stat counter.
	208	*/
	209	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	210	{
b2e8fb6e PZ	211	#ifdef CONFIG_SMP
	212	return nr_cpu_ids * BDI_STAT_BATCH;
	213	#else
	214	return 1;
	215	#endif
e0bf68dd	216	}
1da177e4	217
189d3c4a	218	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	219	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	220
1da177e4 LT	221	/*
1da177e4 LT	222	* Flags in backing_dev_info::capability
e4ad08fe MS	223	*
	224	* The first three flags control whether dirty pages will contribute to the
	225	* VM's accounting and whether writepages() should be called for dirty pages
	226	* (something that would not, for example, be appropriate for ramfs)
	227	*
	228	* WARNING: these flags are closely related and should not normally be
	229	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	230	* three flags into a single convenience macro.
	231	*
	232	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	233	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	234	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	235	*
	236	* These flags let !MMU mmap() govern direct device mapping vs immediate
	237	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	238	*
	239	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	240	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	241	* BDI_CAP_READ_MAP: Can be mapped for reading
	242	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	243	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	244	*
4f98a2fe RR	245	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	246	*/
e4ad08fe MS	247	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	248	#define BDI_CAP_NO_WRITEBACK 0x00000002
	249	#define BDI_CAP_MAP_COPY 0x00000004
	250	#define BDI_CAP_MAP_DIRECT 0x00000008
	251	#define BDI_CAP_READ_MAP 0x00000010
	252	#define BDI_CAP_WRITE_MAP 0x00000020
	253	#define BDI_CAP_EXEC_MAP 0x00000040
	254	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	255	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	256
1da177e4 LT	257	#define BDI_CAP_VMFLAGS \
	258	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	259
e4ad08fe MS	260	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	261	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	262
1da177e4 LT	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;
5129a469	271	extern struct backing_dev_info noop_backing_dev_info;
1da177e4	272
1da177e4	273	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	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	{
1faa16d2	284	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	285	}
	286
	287	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	288	{
1faa16d2	289	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	290	}
	291
	292	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	293	{
1faa16d2 JA	294	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	295	(1 << BDI_async_congested));
1da177e4 LT	296	}
1da177e4 LT	297
373c0a7e TM	298	enum {
	299	BLK_RW_ASYNC = 0,
	300	BLK_RW_SYNC = 1,
	301	};
	302
8aa7e847 JA	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);
0e093d99	306	long wait_iff_congested(struct zone *zone, int sync, long timeout);
3965c9ae WL	307	int pdflush_proc_obsolete(struct ctl_table *table, int write,
3965c9ae WL	308	void __user buffer, size_t lenp, loff_t *ppos);
1da177e4	309
e4ad08fe MS	310	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	311	{
	312	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	313	}
	314
	315	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	316	{
	317	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	318	}
1da177e4	319
e4ad08fe MS	320	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	321	{
	322	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	323	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	324	BDI_CAP_NO_WRITEBACK));
	325	}
1da177e4	326
4f98a2fe RR	327	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	328	{
	329	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	330	}
	331
03ba3782 JA	332	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	333	{
	334	return bdi == &default_backing_dev_info;
	335	}
	336
e4ad08fe MS	337	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	338	{
	339	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	340	}
1da177e4	341
e4ad08fe MS	342	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	343	{
	344	return bdi_cap_account_dirty(mapping->backing_dev_info);
	345	}
1da177e4	346
4f98a2fe RR	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
03ba3782 JA	352	static inline int bdi_sched_wait(void *word)
	353	{
	354	schedule();
	355	return 0;
	356	}
	357
1da177e4	358	#endif /* _LINUX_BACKING_DEV_H */