[linux-block.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);
void __blk_queue_free_tags(struct request_queue *q);

void blk_unplug_work(struct work_struct *work);
void blk_unplug_timeout(unsigned long data);
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 suceeds
 */
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))

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

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

		if (!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);
void blk_recalc_rq_segments(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;
}

#if defined(CONFIG_BLK_DEV_INTEGRITY)

#define rq_for_each_integrity_segment(bvl, _rq, _iter)		\
	__rq_for_each_bio(_iter.bio, _rq)			\
		bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)

#endif /* BLK_DEV_INTEGRITY */

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

/*
 * 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
 */
static inline int blk_do_io_stat(struct request *rq)
{
	return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&
		blk_discard_rq(rq);
}

#endif
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);
8324aa91 JA	16	void __blk_queue_free_tags(struct request_queue *q);
8324aa91 JA	17
86db1e29 JA	18	void blk_unplug_work(struct work_struct *work);
86db1e29 JA	19	void blk_unplug_timeout(unsigned long data);
242f9dcb JA	20	void blk_rq_timed_out_timer(unsigned long data);
	21	void blk_delete_timer(struct request *);
	22	void blk_add_timer(struct request *);
f73e2d13	23	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	24
	25	/*
	26	* Internal atomic flags for request handling
	27	*/
	28	enum rq_atomic_flags {
	29	REQ_ATOM_COMPLETE = 0,
	30	};
	31
	32	/*
	33	* EH timer and IO completion will both attempt to 'grab' the request, make
	34	* sure that only one of them suceeds
	35	*/
	36	static inline int blk_mark_rq_complete(struct request *rq)
	37	{
	38	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	39	}
	40
	41	static inline void blk_clear_rq_complete(struct request *rq)
	42	{
	43	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	44	}
86db1e29	45
158dbda0 TH	46	/*
	47	* Internal elevator interface
	48	*/
	49	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	50
	51	static inline struct request __elv_next_request(struct request_queue q)
	52	{
	53	struct request *rq;
	54
	55	while (1) {
	56	while (!list_empty(&q->queue_head)) {
	57	rq = list_entry_rq(q->queue_head.next);
	58	if (blk_do_ordered(q, &rq))
	59	return rq;
	60	}
	61
	62	if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
	63	return NULL;
	64	}
	65	}
	66
	67	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	68	{
	69	struct elevator_queue *e = q->elevator;
	70
	71	if (e->ops->elevator_activate_req_fn)
	72	e->ops->elevator_activate_req_fn(q, rq);
	73	}
	74
	75	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	76	{
	77	struct elevator_queue *e = q->elevator;
	78
	79	if (e->ops->elevator_deactivate_req_fn)
	80	e->ops->elevator_deactivate_req_fn(q, rq);
	81	}
	82
581d4e28 JA	83	#ifdef CONFIG_FAIL_IO_TIMEOUT
	84	int blk_should_fake_timeout(struct request_queue *);
	85	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	86	ssize_t part_timeout_store(struct device , struct device_attribute ,
	87	const char *, size_t);
	88	#else
	89	static inline int blk_should_fake_timeout(struct request_queue *q)
	90	{
	91	return 0;
	92	}
	93	#endif
	94
86db1e29 JA	95	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	96
d6d48196 JA	97	int ll_back_merge_fn(struct request_queue q, struct request req,
	98	struct bio *bio);
	99	int ll_front_merge_fn(struct request_queue q, struct request req,
	100	struct bio *bio);
	101	int attempt_back_merge(struct request_queue q, struct request rq);
	102	int attempt_front_merge(struct request_queue q, struct request rq);
	103	void blk_recalc_rq_segments(struct request *rq);
d6d48196	104
8324aa91 JA	105	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	106
ff88972c AB	107	int blk_dev_init(void);
ff88972c AB	108
f600abe2 JA	109	void elv_quiesce_start(struct request_queue *q);
f600abe2 JA	110	void elv_quiesce_end(struct request_queue *q);
6c7e8cee JA	111
6c7e8cee JA	112
8324aa91 JA	113	/*
	114	* Return the threshold (number of used requests) at which the queue is
	115	* considered to be congested. It include a little hysteresis to keep the
	116	* context switch rate down.
	117	*/
	118	static inline int queue_congestion_on_threshold(struct request_queue *q)
	119	{
	120	return q->nr_congestion_on;
	121	}
	122
	123	/*
	124	* The threshold at which a queue is considered to be uncongested
	125	*/
	126	static inline int queue_congestion_off_threshold(struct request_queue *q)
	127	{
	128	return q->nr_congestion_off;
	129	}
	130
7ba1ba12 MP	131	#if defined(CONFIG_BLK_DEV_INTEGRITY)
	132
	133	#define rq_for_each_integrity_segment(bvl, _rq, _iter) \
	134	__rq_for_each_bio(_iter.bio, _rq) \
	135	bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
	136
	137	#endif /* BLK_DEV_INTEGRITY */
	138
c7c22e4d JA	139	static inline int blk_cpu_to_group(int cpu)
	140	{
	141	#ifdef CONFIG_SCHED_MC
be4d638c RR	142	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be4d638c RR	143	return cpumask_first(mask);
c7c22e4d	144	#elif defined(CONFIG_SCHED_SMT)
c69fc56d	145	return cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	146	#else
	147	return cpu;
	148	#endif
	149	}
	150
c2553b58 JA	151	/*
	152	* Contribute to IO statistics IFF:
	153	*
	154	* a) it's attached to a gendisk, and
	155	* b) the queue had IO stats enabled when this request was started, and
	156	* c) it's a file system request
	157	*/
26308eab	158	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	159	{
c69d4854 JA	160	return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&
c69d4854 JA	161	blk_discard_rq(rq);
fb8ec18c JA	162	}
fb8ec18c JA	163
8324aa91	164	#endif