[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/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 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 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	77	unsigned long bw_time_stamp; /* last time write bw is updated */
be3ffa27	78	unsigned long dirtied_stamp;
e98be2d5 WF	79	unsigned long written_stamp; /* pages written at bw_time_stamp */
	80	unsigned long write_bandwidth; /* the estimated write bandwidth */
	81	unsigned long avg_write_bandwidth; /* further smoothed write bw */
	82
be3ffa27 WF	83	/*
	84	* The base dirty throttle rate, re-calculated on every 200ms.
	85	* All the bdi tasks' dirty rate will be curbed under it.
7381131c WF	86	* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
7381131c WF	87	* in small steps and is much more smooth/stable than the latter.
be3ffa27 WF	88	*/
be3ffa27 WF	89	unsigned long dirty_ratelimit;
7381131c	90	unsigned long balanced_dirty_ratelimit;
be3ffa27	91
04fbfdc1 PZ	92	struct prop_local_percpu completions;
04fbfdc1 PZ	93	int dirty_exceeded;
cf0ca9fe	94
189d3c4a	95	unsigned int min_ratio;
a42dde04	96	unsigned int max_ratio, max_prop_frac;
189d3c4a	97
03ba3782	98	struct bdi_writeback wb; /* default writeback info for this bdi */
c1955ce3	99	spinlock_t wb_lock; /* protects work_list */
76f1418b	100
03ba3782 JA	101	struct list_head work_list;
	102
	103	struct device *dev;
66f3b8e2	104
31373d09 MG	105	struct timer_list laptop_mode_wb_timer;
31373d09 MG	106
76f1418b MS	107	#ifdef CONFIG_DEBUG_FS
	108	struct dentry *debug_dir;
	109	struct dentry *debug_stats;
	110	#endif
1da177e4 LT	111	};
1da177e4 LT	112
b2e8fb6e PZ	113	int bdi_init(struct backing_dev_info *bdi);
	114	void bdi_destroy(struct backing_dev_info *bdi);
	115
cf0ca9fe PZ	116	int bdi_register(struct backing_dev_info bdi, struct device parent,
	117	const char *fmt, ...);
	118	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
	119	void bdi_unregister(struct backing_dev_info *bdi);
c3c53206	120	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
c5444198 CH	121	void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
c5444198 CH	122	void bdi_start_background_writeback(struct backing_dev_info *bdi);
08243900	123	int bdi_writeback_thread(void *data);
03ba3782	124	int bdi_has_dirty_io(struct backing_dev_info *bdi);
6423104b	125	void bdi_arm_supers_timer(void);
6467716a	126	void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
f758eeab	127	void bdi_lock_two(struct bdi_writeback wb1, struct bdi_writeback wb2);
cf0ca9fe	128
03ba3782	129	extern spinlock_t bdi_lock;
66f3b8e2	130	extern struct list_head bdi_list;
92c09c04	131	extern struct list_head bdi_pending_list;
66f3b8e2	132
03ba3782 JA	133	static inline int wb_has_dirty_io(struct bdi_writeback *wb)
	134	{
	135	return !list_empty(&wb->b_dirty) \|\|
	136	!list_empty(&wb->b_io) \|\|
	137	!list_empty(&wb->b_more_io);
	138	}
	139
b2e8fb6e PZ	140	static inline void __add_bdi_stat(struct backing_dev_info *bdi,
	141	enum bdi_stat_item item, s64 amount)
	142	{
	143	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
	144	}
	145
	146	static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
	147	enum bdi_stat_item item)
	148	{
	149	__add_bdi_stat(bdi, item, 1);
	150	}
	151
	152	static inline void inc_bdi_stat(struct backing_dev_info *bdi,
	153	enum bdi_stat_item item)
	154	{
	155	unsigned long flags;
	156
	157	local_irq_save(flags);
	158	__inc_bdi_stat(bdi, item);
	159	local_irq_restore(flags);
	160	}
	161
	162	static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
	163	enum bdi_stat_item item)
	164	{
	165	__add_bdi_stat(bdi, item, -1);
	166	}
	167
	168	static inline void dec_bdi_stat(struct backing_dev_info *bdi,
	169	enum bdi_stat_item item)
	170	{
	171	unsigned long flags;
	172
	173	local_irq_save(flags);
	174	__dec_bdi_stat(bdi, item);
	175	local_irq_restore(flags);
	176	}
	177
	178	static inline s64 bdi_stat(struct backing_dev_info *bdi,
	179	enum bdi_stat_item item)
	180	{
	181	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
	182	}
	183
	184	static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
	185	enum bdi_stat_item item)
	186	{
	187	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
	188	}
	189
	190	static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
	191	enum bdi_stat_item item)
e0bf68dd	192	{
b2e8fb6e PZ	193	s64 sum;
	194	unsigned long flags;
	195
	196	local_irq_save(flags);
	197	sum = __bdi_stat_sum(bdi, item);
	198	local_irq_restore(flags);
	199
	200	return sum;
e0bf68dd PZ	201	}
e0bf68dd PZ	202
dd5656e5 MS	203	extern void bdi_writeout_inc(struct backing_dev_info *bdi);
dd5656e5 MS	204
b2e8fb6e PZ	205	/*
	206	* maximal error of a stat counter.
	207	*/
	208	static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
e0bf68dd	209	{
b2e8fb6e PZ	210	#ifdef CONFIG_SMP
	211	return nr_cpu_ids * BDI_STAT_BATCH;
	212	#else
	213	return 1;
	214	#endif
e0bf68dd	215	}
1da177e4	216
189d3c4a	217	int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
a42dde04	218	int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
189d3c4a	219
1da177e4 LT	220	/*
1da177e4 LT	221	* Flags in backing_dev_info::capability
e4ad08fe MS	222	*
	223	* The first three flags control whether dirty pages will contribute to the
	224	* VM's accounting and whether writepages() should be called for dirty pages
	225	* (something that would not, for example, be appropriate for ramfs)
	226	*
	227	* WARNING: these flags are closely related and should not normally be
	228	* used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	229	* three flags into a single convenience macro.
	230	*
	231	* BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	232	* BDI_CAP_NO_WRITEBACK: Don't write pages back
	233	* BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	234	*
	235	* These flags let !MMU mmap() govern direct device mapping vs immediate
	236	* copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	237	*
	238	* BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	239	* BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	240	* BDI_CAP_READ_MAP: Can be mapped for reading
	241	* BDI_CAP_WRITE_MAP: Can be mapped for writing
	242	* BDI_CAP_EXEC_MAP: Can be mapped for execution
4f98a2fe RR	243	*
4f98a2fe RR	244	* BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
1da177e4	245	*/
e4ad08fe MS	246	#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	247	#define BDI_CAP_NO_WRITEBACK 0x00000002
	248	#define BDI_CAP_MAP_COPY 0x00000004
	249	#define BDI_CAP_MAP_DIRECT 0x00000008
	250	#define BDI_CAP_READ_MAP 0x00000010
	251	#define BDI_CAP_WRITE_MAP 0x00000020
	252	#define BDI_CAP_EXEC_MAP 0x00000040
	253	#define BDI_CAP_NO_ACCT_WB 0x00000080
4f98a2fe	254	#define BDI_CAP_SWAP_BACKED 0x00000100
e4ad08fe	255
1da177e4 LT	256	#define BDI_CAP_VMFLAGS \
	257	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
	258
e4ad08fe MS	259	#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	260	(BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	261
1da177e4 LT	262	#if defined(VM_MAYREAD) && \
	263	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
	264	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
	265	BDI_CAP_EXEC_MAP != VM_MAYEXEC)
	266	#error please change backing_dev_info::capabilities flags
	267	#endif
	268
	269	extern struct backing_dev_info default_backing_dev_info;
5129a469	270	extern struct backing_dev_info noop_backing_dev_info;
1da177e4	271
1da177e4	272	int writeback_in_progress(struct backing_dev_info *bdi);
1da177e4 LT	273
	274	static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
	275	{
	276	if (bdi->congested_fn)
	277	return bdi->congested_fn(bdi->congested_data, bdi_bits);
	278	return (bdi->state & bdi_bits);
	279	}
	280
	281	static inline int bdi_read_congested(struct backing_dev_info *bdi)
	282	{
1faa16d2	283	return bdi_congested(bdi, 1 << BDI_sync_congested);
1da177e4 LT	284	}
	285
	286	static inline int bdi_write_congested(struct backing_dev_info *bdi)
	287	{
1faa16d2	288	return bdi_congested(bdi, 1 << BDI_async_congested);
1da177e4 LT	289	}
	290
	291	static inline int bdi_rw_congested(struct backing_dev_info *bdi)
	292	{
1faa16d2 JA	293	return bdi_congested(bdi, (1 << BDI_sync_congested) \|
1faa16d2 JA	294	(1 << BDI_async_congested));
1da177e4 LT	295	}
1da177e4 LT	296
373c0a7e TM	297	enum {
	298	BLK_RW_ASYNC = 0,
	299	BLK_RW_SYNC = 1,
	300	};
	301
8aa7e847 JA	302	void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
	303	void set_bdi_congested(struct backing_dev_info *bdi, int sync);
	304	long congestion_wait(int sync, long timeout);
0e093d99	305	long wait_iff_congested(struct zone *zone, int sync, long timeout);
1da177e4	306
e4ad08fe MS	307	static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	308	{
	309	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	310	}
	311
	312	static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	313	{
	314	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	315	}
1da177e4	316
e4ad08fe MS	317	static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	318	{
	319	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	320	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	321	BDI_CAP_NO_WRITEBACK));
	322	}
1da177e4	323
4f98a2fe RR	324	static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
	325	{
	326	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
	327	}
	328
03ba3782 JA	329	static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
	330	{
	331	return bdi == &default_backing_dev_info;
	332	}
	333
e4ad08fe MS	334	static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	335	{
	336	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	337	}
1da177e4	338
e4ad08fe MS	339	static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	340	{
	341	return bdi_cap_account_dirty(mapping->backing_dev_info);
	342	}
1da177e4	343
4f98a2fe RR	344	static inline bool mapping_cap_swap_backed(struct address_space *mapping)
	345	{
	346	return bdi_cap_swap_backed(mapping->backing_dev_info);
	347	}
	348
03ba3782 JA	349	static inline int bdi_sched_wait(void *word)
	350	{
	351	schedule();
	352	return 0;
	353	}
	354
1da177e4	355	#endif /* _LINUX_BACKING_DEV_H */