[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/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>

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 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 */

	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);
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);

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>
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>
60063497	19	#include <linux/atomic.h>
1da177e4	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 */
81d73a32	34	BDI_writeback_running, /* Writeback is in progress */
1da177e4 LT	35	BDI_unused, /* Available bits start here */
	36	};
	37
	38	typedef int (congested_fn)(void *, int);
	39
b2e8fb6e	40	enum bdi_stat_item {
c9e51e41	41	BDI_RECLAIMABLE,
69cb51d1	42	BDI_WRITEBACK,
c8e28ce0	43	BDI_DIRTIED,
f7d2b1ec	44	BDI_WRITTEN,
b2e8fb6e PZ	45	NR_BDI_STAT_ITEMS
	46	};
	47
	48	#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
	49
03ba3782	50	struct bdi_writeback {
ecd58403	51	struct backing_dev_info bdi; / our parent bdi */
03ba3782 JA	52	unsigned int nr;
03ba3782 JA	53
ecd58403 AB	54	unsigned long last_old_flush; /* last old data flush */
ecd58403 AB	55	unsigned long last_active; /* last time bdi thread was active */
03ba3782	56
ecd58403	57	struct task_struct task; / writeback thread */
6467716a	58	struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */
ecd58403 AB	59	struct list_head b_dirty; /* dirty inodes */
	60	struct list_head b_io; /* parked for writeback */
	61	struct list_head b_more_io; /* parked for more writeback */
f758eeab	62	spinlock_t list_lock; /* protects the b_* lists */
03ba3782 JA	63	};
03ba3782 JA	64
1da177e4	65	struct backing_dev_info {
66f3b8e2	66	struct list_head bdi_list;
1da177e4 LT	67	unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
	68	unsigned long state; /* Always use atomic bitops on this */
	69	unsigned int capabilities; /* Device capabilities */
	70	congested_fn congested_fn; / Function pointer if device is md/dm */
	71	void congested_data; / Pointer to aux data for congested func */
b2e8fb6e	72
d993831f JA	73	char *name;
d993831f JA	74
b2e8fb6e	75	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
04fbfdc1	76
e98be2d5 WF	77	unsigned long bw_time_stamp; /* last time write bw is updated */
	78	unsigned long written_stamp; /* pages written at bw_time_stamp */
	79	unsigned long write_bandwidth; /* the estimated write bandwidth */
	80	unsigned long avg_write_bandwidth; /* further smoothed write bw */
	81
04fbfdc1 PZ	82	struct prop_local_percpu completions;
04fbfdc1 PZ	83	int dirty_exceeded;
cf0ca9fe	84
189d3c4a	85	unsigned int min_ratio;
a42dde04	86	unsigned int max_ratio, max_prop_frac;
189d3c4a	87
03ba3782	88	struct bdi_writeback wb; /* default writeback info for this bdi */
c1955ce3	89	spinlock_t wb_lock; /* protects work_list */
76f1418b	90
03ba3782 JA	91	struct list_head work_list;
	92
	93	struct device *dev;
66f3b8e2	94
31373d09 MG	95	struct timer_list laptop_mode_wb_timer;
31373d09 MG	96
76f1418b MS	97	#ifdef CONFIG_DEBUG_FS
	98	struct dentry *debug_dir;
	99	struct dentry *debug_stats;
	100	#endif
1da177e4 LT	101	};
1da177e4 LT	102
b2e8fb6e PZ	103	int bdi_init(struct backing_dev_info *bdi);
	104	void bdi_destroy(struct backing_dev_info *bdi);
	105
cf0ca9fe PZ	106	int bdi_register(struct backing_dev_info bdi, struct device parent,
	107	const char *fmt, ...);
	108	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	109	void bdi_unregister(struct backing_dev_info *bdi);
c3c53206	110	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
c5444198 CH	111	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
c5444198 CH	112	void bdi_start_background_writeback(struct backing_dev_info *bdi);
08243900	113	int bdi_writeback_thread(void *data);
03ba3782	114	int bdi_has_dirty_io(struct backing_dev_info *bdi);
6423104b	115	void bdi_arm_supers_timer(void);
6467716a	116	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
f758eeab	117	void bdi_lock_two(struct bdi_writeback wb1, struct bdi_writeback wb2);
cf0ca9fe	118
03ba3782	119	extern spinlock_t bdi_lock;
66f3b8e2	120	extern struct list_head bdi_list;
92c09c04	121	extern struct list_head bdi_pending_list;
66f3b8e2	122
03ba3782 JA	123	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	124	{
	125	return !list_empty(&wb->b_dirty) \|\|
	126	!list_empty(&wb->b_io) \|\|
	127	!list_empty(&wb->b_more_io);
	128	}
	129
b2e8fb6e PZ	130	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	131	enum bdi_stat_item item, s64 amount)
	132	{
	133	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	134	}
	135
	136	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	137	enum bdi_stat_item item)
	138	{
	139	__add_bdi_stat(bdi, item, 1);
	140	}
	141
	142	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	143	enum bdi_stat_item item)
	144	{
	145	unsigned long flags;
	146
	147	local_irq_save(flags);
	148	__inc_bdi_stat(bdi, item);
	149	local_irq_restore(flags);
	150	}
	151
	152	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	153	enum bdi_stat_item item)
	154	{
	155	__add_bdi_stat(bdi, item, -1);
	156	}
	157
	158	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	159	enum bdi_stat_item item)
	160	{
	161	unsigned long flags;
	162
	163	local_irq_save(flags);
	164	__dec_bdi_stat(bdi, item);
	165	local_irq_restore(flags);
	166	}
	167
	168	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	169	enum bdi_stat_item item)
	170	{
	171	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	172	}
	173
	174	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	175	enum bdi_stat_item item)
	176	{
	177	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	178	}
	179
	180	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	181	enum bdi_stat_item item)
e0bf68dd	182	{
b2e8fb6e PZ	183	s64 sum;
	184	unsigned long flags;
	185
	186	local_irq_save(flags);
	187	sum = __bdi_stat_sum(bdi, item);
	188	local_irq_restore(flags);
	189
	190	return sum;
e0bf68dd PZ	191	}
e0bf68dd PZ	192
dd5656e5 MS	193	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	194
b2e8fb6e PZ	195	/*
	196	* maximal error of a stat counter.
	197	*/
	198	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	199	{
b2e8fb6e PZ	200	#ifdef CONFIG_SMP
	201	return nr_cpu_ids * BDI_STAT_BATCH;
	202	#else
	203	return 1;
	204	#endif
e0bf68dd	205	}
1da177e4	206
189d3c4a	207	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	208	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	209
1da177e4 LT	210	/*
1da177e4 LT	211	* Flags in backing_dev_info::capability
e4ad08fe MS	212	*
	213	* The first three flags control whether dirty pages will contribute to the
	214	* VM's accounting and whether writepages() should be called for dirty pages
	215	* (something that would not, for example, be appropriate for ramfs)
	216	*
	217	* WARNING: these flags are closely related and should not normally be
	218	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	219	* three flags into a single convenience macro.
	220	*
	221	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	222	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	223	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	224	*
	225	* These flags let !MMU mmap() govern direct device mapping vs immediate
	226	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	227	*
	228	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	229	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	230	* BDI_CAP_READ_MAP: Can be mapped for reading
	231	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	232	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	233	*
4f98a2fe RR	234	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	235	*/
e4ad08fe MS	236	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	237	#define BDI_CAP_NO_WRITEBACK 0x00000002
	238	#define BDI_CAP_MAP_COPY 0x00000004
	239	#define BDI_CAP_MAP_DIRECT 0x00000008
	240	#define BDI_CAP_READ_MAP 0x00000010
	241	#define BDI_CAP_WRITE_MAP 0x00000020
	242	#define BDI_CAP_EXEC_MAP 0x00000040
	243	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	244	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	245
1da177e4 LT	246	#define BDI_CAP_VMFLAGS \
	247	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	248
e4ad08fe MS	249	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	250	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	251
1da177e4 LT	252	#if defined(VM_MAYREAD) && \
	253	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	254	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	255	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	256	#error please change backing_dev_info::capabilities flags
	257	#endif
	258
	259	extern struct backing_dev_info default_backing_dev_info;
5129a469	260	extern struct backing_dev_info noop_backing_dev_info;
1da177e4	261
1da177e4	262	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	263
	264	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	265	{
	266	if (bdi->congested_fn)
	267	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	268	return (bdi->state & bdi_bits);
	269	}
	270
	271	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	272	{
1faa16d2	273	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	274	}
	275
	276	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	277	{
1faa16d2	278	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	279	}
	280
	281	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	282	{
1faa16d2 JA	283	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	284	(1 << BDI_async_congested));
1da177e4 LT	285	}
1da177e4 LT	286
373c0a7e TM	287	enum {
	288	BLK_RW_ASYNC = 0,
	289	BLK_RW_SYNC = 1,
	290	};
	291
8aa7e847 JA	292	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	293	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	294	long congestion_wait(int sync, long timeout);
0e093d99	295	long wait_iff_congested(struct zone *zone, int sync, long timeout);
1da177e4	296
e4ad08fe MS	297	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	298	{
	299	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	300	}
	301
	302	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	303	{
	304	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	305	}
1da177e4	306
e4ad08fe MS	307	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	308	{
	309	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	310	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	311	BDI_CAP_NO_WRITEBACK));
	312	}
1da177e4	313
4f98a2fe RR	314	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	315	{
	316	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	317	}
	318
03ba3782 JA	319	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	320	{
	321	return bdi == &default_backing_dev_info;
	322	}
	323
e4ad08fe MS	324	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	325	{
	326	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	327	}
1da177e4	328
e4ad08fe MS	329	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	330	{
	331	return bdi_cap_account_dirty(mapping->backing_dev_info);
	332	}
1da177e4	333
4f98a2fe RR	334	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	335	{
	336	return bdi_cap_swap_backed(mapping->backing_dev_info);
	337	}
	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 */