[linux.git] / block / blk.h

#ifndef BLK_INTERNAL_H
#define BLK_INTERNAL_H

/* Amount of time in which a process may batch requests */
#define BLK_BATCH_TIME	(HZ/50UL)

/* Number of requests a "batching" process may submit */
#define BLK_BATCH_REQ	32

extern struct kmem_cache *blk_requestq_cachep;
extern struct kobj_type blk_queue_ktype;

void init_request_from_bio(struct request *req, struct bio *bio);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
			struct bio *bio);
int blk_rq_append_bio(struct request_queue *q, struct request *rq,
		      struct bio *bio);
void blk_drain_queue(struct request_queue *q, bool drain_all);
void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);
bool __blk_end_bidi_request(struct request *rq, int error,
			    unsigned int nr_bytes, unsigned int bidi_bytes);

void blk_rq_timed_out_timer(unsigned long data);
void blk_delete_timer(struct request *);
void blk_add_timer(struct request *);
void __generic_unplug_device(struct request_queue *);

/*
 * Internal atomic flags for request handling
 */
enum rq_atomic_flags {
	REQ_ATOM_COMPLETE = 0,
};

/*
 * EH timer and IO completion will both attempt to 'grab' the request, make
 * sure that only one of them succeeds
 */
static inline int blk_mark_rq_complete(struct request *rq)
{
	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
}

static inline void blk_clear_rq_complete(struct request *rq)
{
	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
}

/*
 * Internal elevator interface
 */
#define ELV_ON_HASH(rq)		(!hlist_unhashed(&(rq)->hash))

void blk_insert_flush(struct request *rq);
void blk_abort_flushes(struct request_queue *q);

static inline struct request *__elv_next_request(struct request_queue *q)
{
	struct request *rq;

	while (1) {
		if (!list_empty(&q->queue_head)) {
			rq = list_entry_rq(q->queue_head.next);
			return rq;
		}

		/*
		 * Flush request is running and flush request isn't queueable
		 * in the drive, we can hold the queue till flush request is
		 * finished. Even we don't do this, driver can't dispatch next
		 * requests and will requeue them. And this can improve
		 * throughput too. For example, we have request flush1, write1,
		 * flush 2. flush1 is dispatched, then queue is hold, write1
		 * isn't inserted to queue. After flush1 is finished, flush2
		 * will be dispatched. Since disk cache is already clean,
		 * flush2 will be finished very soon, so looks like flush2 is
		 * folded to flush1.
		 * Since the queue is hold, a flag is set to indicate the queue
		 * should be restarted later. Please see flush_end_io() for
		 * details.
		 */
		if (q->flush_pending_idx != q->flush_running_idx &&
				!queue_flush_queueable(q)) {
			q->flush_queue_delayed = 1;
			return NULL;
		}
		if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
		    !q->elevator->ops->elevator_dispatch_fn(q, 0))
			return NULL;
	}
}

static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
{
	struct elevator_queue *e = q->elevator;

	if (e->ops->elevator_activate_req_fn)
		e->ops->elevator_activate_req_fn(q, rq);
}

static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
{
	struct elevator_queue *e = q->elevator;

	if (e->ops->elevator_deactivate_req_fn)
		e->ops->elevator_deactivate_req_fn(q, rq);
}

#ifdef CONFIG_FAIL_IO_TIMEOUT
int blk_should_fake_timeout(struct request_queue *);
ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
ssize_t part_timeout_store(struct device *, struct device_attribute *,
				const char *, size_t);
#else
static inline int blk_should_fake_timeout(struct request_queue *q)
{
	return 0;
}
#endif

struct io_context *current_io_context(gfp_t gfp_flags, int node);

int ll_back_merge_fn(struct request_queue *q, struct request *req,
		     struct bio *bio);
int ll_front_merge_fn(struct request_queue *q, struct request *req, 
		      struct bio *bio);
int attempt_back_merge(struct request_queue *q, struct request *rq);
int attempt_front_merge(struct request_queue *q, struct request *rq);
int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
				struct request *next);
void blk_recalc_rq_segments(struct request *rq);
void blk_rq_set_mixed_merge(struct request *rq);

void blk_queue_congestion_threshold(struct request_queue *q);

int blk_dev_init(void);

void elv_quiesce_start(struct request_queue *q);
void elv_quiesce_end(struct request_queue *q);


/*
 * Return the threshold (number of used requests) at which the queue is
 * considered to be congested.  It include a little hysteresis to keep the
 * context switch rate down.
 */
static inline int queue_congestion_on_threshold(struct request_queue *q)
{
	return q->nr_congestion_on;
}

/*
 * The threshold at which a queue is considered to be uncongested
 */
static inline int queue_congestion_off_threshold(struct request_queue *q)
{
	return q->nr_congestion_off;
}

static inline int blk_cpu_to_group(int cpu)
{
	int group = NR_CPUS;
#ifdef CONFIG_SCHED_MC
	const struct cpumask *mask = cpu_coregroup_mask(cpu);
	group = cpumask_first(mask);
#elif defined(CONFIG_SCHED_SMT)
	group = cpumask_first(topology_thread_cpumask(cpu));
#else
	return cpu;
#endif
	if (likely(group < NR_CPUS))
		return group;
	return cpu;
}

/*
 * Contribute to IO statistics IFF:
 *
 *	a) it's attached to a gendisk, and
 *	b) the queue had IO stats enabled when this request was started, and
 *	c) it's a file system request or a discard request
 */
static inline int blk_do_io_stat(struct request *rq)
{
	return rq->rq_disk &&
	       (rq->cmd_flags & REQ_IO_STAT) &&
	       (rq->cmd_type == REQ_TYPE_FS ||
	        (rq->cmd_flags & REQ_DISCARD));
}

#ifdef CONFIG_BLK_DEV_THROTTLING
extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
extern void blk_throtl_drain(struct request_queue *q);
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
extern void blk_throtl_release(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
{
	return false;
}
static inline void blk_throtl_drain(struct request_queue *q) { }
static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline void blk_throtl_exit(struct request_queue *q) { }
static inline void blk_throtl_release(struct request_queue *q) { }
#endif /* CONFIG_BLK_DEV_THROTTLING */

#endif /* BLK_INTERNAL_H */
Commit	Line	Data
8324aa91 JA	1	#ifndef BLK_INTERNAL_H
	2	#define BLK_INTERNAL_H
	3
86db1e29 JA	4	/* Amount of time in which a process may batch requests */
	5	#define BLK_BATCH_TIME (HZ/50UL)
	6
	7	/* Number of requests a "batching" process may submit */
	8	#define BLK_BATCH_REQ 32
	9
8324aa91 JA	10	extern struct kmem_cache *blk_requestq_cachep;
	11	extern struct kobj_type blk_queue_ktype;
	12
86db1e29 JA	13	void init_request_from_bio(struct request req, struct bio bio);
	14	void blk_rq_bio_prep(struct request_queue q, struct request rq,
	15	struct bio *bio);
a411f4bb BH	16	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	17	struct bio *bio);
c9a929dd	18	void blk_drain_queue(struct request_queue *q, bool drain_all);
9934c8c0	19	void blk_dequeue_request(struct request *rq);
8324aa91	20	void __blk_queue_free_tags(struct request_queue *q);
4853abaa JM	21	bool __blk_end_bidi_request(struct request *rq, int error,
4853abaa JM	22	unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91	23
242f9dcb JA	24	void blk_rq_timed_out_timer(unsigned long data);
	25	void blk_delete_timer(struct request *);
	26	void blk_add_timer(struct request *);
f73e2d13	27	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	28
	29	/*
	30	* Internal atomic flags for request handling
	31	*/
	32	enum rq_atomic_flags {
	33	REQ_ATOM_COMPLETE = 0,
	34	};
	35
	36	/*
	37	* EH timer and IO completion will both attempt to 'grab' the request, make
25985edc	38	* sure that only one of them succeeds
242f9dcb JA	39	*/
	40	static inline int blk_mark_rq_complete(struct request *rq)
	41	{
	42	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	43	}
	44
	45	static inline void blk_clear_rq_complete(struct request *rq)
	46	{
	47	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	48	}
86db1e29	49
158dbda0 TH	50	/*
	51	* Internal elevator interface
	52	*/
	53	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	54
ae1b1539 TH	55	void blk_insert_flush(struct request *rq);
ae1b1539 TH	56	void blk_abort_flushes(struct request_queue *q);
dd831006	57
158dbda0 TH	58	static inline struct request __elv_next_request(struct request_queue q)
	59	{
	60	struct request *rq;
	61
	62	while (1) {
ae1b1539	63	if (!list_empty(&q->queue_head)) {
158dbda0	64	rq = list_entry_rq(q->queue_head.next);
ae1b1539	65	return rq;
158dbda0 TH	66	}
158dbda0 TH	67
3ac0cc45	68	/*
	69	* Flush request is running and flush request isn't queueable
	70	* in the drive, we can hold the queue till flush request is
	71	* finished. Even we don't do this, driver can't dispatch next
	72	* requests and will requeue them. And this can improve
	73	* throughput too. For example, we have request flush1, write1,
	74	* flush 2. flush1 is dispatched, then queue is hold, write1
	75	* isn't inserted to queue. After flush1 is finished, flush2
	76	* will be dispatched. Since disk cache is already clean,
	77	* flush2 will be finished very soon, so looks like flush2 is
	78	* folded to flush1.
	79	* Since the queue is hold, a flag is set to indicate the queue
	80	* should be restarted later. Please see flush_end_io() for
	81	* details.
	82	*/
	83	if (q->flush_pending_idx != q->flush_running_idx &&
	84	!queue_flush_queueable(q)) {
	85	q->flush_queue_delayed = 1;
	86	return NULL;
	87	}
0a58e077 JB	88	if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) \|\|
0a58e077 JB	89	!q->elevator->ops->elevator_dispatch_fn(q, 0))
158dbda0 TH	90	return NULL;
	91	}
	92	}
	93
	94	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	95	{
	96	struct elevator_queue *e = q->elevator;
	97
	98	if (e->ops->elevator_activate_req_fn)
	99	e->ops->elevator_activate_req_fn(q, rq);
	100	}
	101
	102	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	103	{
	104	struct elevator_queue *e = q->elevator;
	105
	106	if (e->ops->elevator_deactivate_req_fn)
	107	e->ops->elevator_deactivate_req_fn(q, rq);
	108	}
	109
581d4e28 JA	110	#ifdef CONFIG_FAIL_IO_TIMEOUT
	111	int blk_should_fake_timeout(struct request_queue *);
	112	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	113	ssize_t part_timeout_store(struct device , struct device_attribute ,
	114	const char *, size_t);
	115	#else
	116	static inline int blk_should_fake_timeout(struct request_queue *q)
	117	{
	118	return 0;
	119	}
	120	#endif
	121
86db1e29 JA	122	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	123
d6d48196 JA	124	int ll_back_merge_fn(struct request_queue q, struct request req,
	125	struct bio *bio);
	126	int ll_front_merge_fn(struct request_queue q, struct request req,
	127	struct bio *bio);
	128	int attempt_back_merge(struct request_queue q, struct request rq);
	129	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	130	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	131	struct request *next);
d6d48196	132	void blk_recalc_rq_segments(struct request *rq);
80a761fd	133	void blk_rq_set_mixed_merge(struct request *rq);
d6d48196	134
8324aa91 JA	135	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	136
ff88972c AB	137	int blk_dev_init(void);
ff88972c AB	138
f253b86b JA	139	void elv_quiesce_start(struct request_queue *q);
	140	void elv_quiesce_end(struct request_queue *q);
	141
	142
8324aa91 JA	143	/*
	144	* Return the threshold (number of used requests) at which the queue is
	145	* considered to be congested. It include a little hysteresis to keep the
	146	* context switch rate down.
	147	*/
	148	static inline int queue_congestion_on_threshold(struct request_queue *q)
	149	{
	150	return q->nr_congestion_on;
	151	}
	152
	153	/*
	154	* The threshold at which a queue is considered to be uncongested
	155	*/
	156	static inline int queue_congestion_off_threshold(struct request_queue *q)
	157	{
	158	return q->nr_congestion_off;
	159	}
	160
c7c22e4d JA	161	static inline int blk_cpu_to_group(int cpu)
c7c22e4d JA	162	{
be14eb61	163	int group = NR_CPUS;
c7c22e4d	164	#ifdef CONFIG_SCHED_MC
be4d638c	165	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be14eb61	166	group = cpumask_first(mask);
c7c22e4d	167	#elif defined(CONFIG_SCHED_SMT)
be14eb61	168	group = cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	169	#else
	170	return cpu;
	171	#endif
be14eb61 BK	172	if (likely(group < NR_CPUS))
	173	return group;
	174	return cpu;
c7c22e4d JA	175	}
c7c22e4d JA	176
c2553b58 JA	177	/*
	178	* Contribute to IO statistics IFF:
	179	*
	180	* a) it's attached to a gendisk, and
	181	* b) the queue had IO stats enabled when this request was started, and
3c4198e8	182	* c) it's a file system request or a discard request
c2553b58	183	*/
26308eab	184	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	185	{
33659ebb CH	186	return rq->rq_disk &&
	187	(rq->cmd_flags & REQ_IO_STAT) &&
	188	(rq->cmd_type == REQ_TYPE_FS \|\|
	189	(rq->cmd_flags & REQ_DISCARD));
fb8ec18c JA	190	}
fb8ec18c JA	191
bc9fcbf9	192	#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9	193	extern bool blk_throtl_bio(struct request_queue q, struct bio bio);
c9a929dd	194	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	195	extern int blk_throtl_init(struct request_queue *q);
bc9fcbf9 TH	196	extern void blk_throtl_exit(struct request_queue *q);
c9a929dd	197	extern void blk_throtl_release(struct request_queue *q);
bc9fcbf9	198	#else /* CONFIG_BLK_DEV_THROTTLING */
bc16a4f9	199	static inline bool blk_throtl_bio(struct request_queue q, struct bio bio)
bc9fcbf9	200	{
bc16a4f9	201	return false;
bc9fcbf9	202	}
c9a929dd	203	static inline void blk_throtl_drain(struct request_queue *q) { }
bc9fcbf9 TH	204	static inline int blk_throtl_init(struct request_queue *q) { return 0; }
bc9fcbf9 TH	205	static inline void blk_throtl_exit(struct request_queue *q) { }
c9a929dd	206	static inline void blk_throtl_release(struct request_queue *q) { }
bc9fcbf9 TH	207	#endif /* CONFIG_BLK_DEV_THROTTLING */
	208
	209	#endif /* BLK_INTERNAL_H */