[deliverable/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);
void blk_dequeue_request(struct request *rq);
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);
9934c8c0	16	void blk_dequeue_request(struct request *rq);
8324aa91 JA	17	void __blk_queue_free_tags(struct request_queue *q);
8324aa91 JA	18
86db1e29 JA	19	void blk_unplug_work(struct work_struct *work);
86db1e29 JA	20	void blk_unplug_timeout(unsigned long data);
242f9dcb JA	21	void blk_rq_timed_out_timer(unsigned long data);
	22	void blk_delete_timer(struct request *);
	23	void blk_add_timer(struct request *);
f73e2d13	24	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	25
	26	/*
	27	* Internal atomic flags for request handling
	28	*/
	29	enum rq_atomic_flags {
	30	REQ_ATOM_COMPLETE = 0,
	31	};
	32
	33	/*
	34	* EH timer and IO completion will both attempt to 'grab' the request, make
	35	* sure that only one of them suceeds
	36	*/
	37	static inline int blk_mark_rq_complete(struct request *rq)
	38	{
	39	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	40	}
	41
	42	static inline void blk_clear_rq_complete(struct request *rq)
	43	{
	44	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	45	}
86db1e29	46
158dbda0 TH	47	/*
	48	* Internal elevator interface
	49	*/
	50	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	51
	52	static inline struct request __elv_next_request(struct request_queue q)
	53	{
	54	struct request *rq;
	55
	56	while (1) {
	57	while (!list_empty(&q->queue_head)) {
	58	rq = list_entry_rq(q->queue_head.next);
	59	if (blk_do_ordered(q, &rq))
	60	return rq;
	61	}
	62
	63	if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
	64	return NULL;
	65	}
	66	}
	67
	68	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	69	{
	70	struct elevator_queue *e = q->elevator;
	71
	72	if (e->ops->elevator_activate_req_fn)
	73	e->ops->elevator_activate_req_fn(q, rq);
	74	}
	75
	76	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	77	{
	78	struct elevator_queue *e = q->elevator;
	79
	80	if (e->ops->elevator_deactivate_req_fn)
	81	e->ops->elevator_deactivate_req_fn(q, rq);
	82	}
	83
581d4e28 JA	84	#ifdef CONFIG_FAIL_IO_TIMEOUT
	85	int blk_should_fake_timeout(struct request_queue *);
	86	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	87	ssize_t part_timeout_store(struct device , struct device_attribute ,
	88	const char *, size_t);
	89	#else
	90	static inline int blk_should_fake_timeout(struct request_queue *q)
	91	{
	92	return 0;
	93	}
	94	#endif
	95
86db1e29 JA	96	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	97
d6d48196 JA	98	int ll_back_merge_fn(struct request_queue q, struct request req,
	99	struct bio *bio);
	100	int ll_front_merge_fn(struct request_queue q, struct request req,
	101	struct bio *bio);
	102	int attempt_back_merge(struct request_queue q, struct request rq);
	103	int attempt_front_merge(struct request_queue q, struct request rq);
	104	void blk_recalc_rq_segments(struct request *rq);
d6d48196	105
8324aa91 JA	106	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	107
ff88972c AB	108	int blk_dev_init(void);
ff88972c AB	109
f600abe2 JA	110	void elv_quiesce_start(struct request_queue *q);
f600abe2 JA	111	void elv_quiesce_end(struct request_queue *q);
6c7e8cee JA	112
6c7e8cee JA	113
8324aa91 JA	114	/*
	115	* Return the threshold (number of used requests) at which the queue is
	116	* considered to be congested. It include a little hysteresis to keep the
	117	* context switch rate down.
	118	*/
	119	static inline int queue_congestion_on_threshold(struct request_queue *q)
	120	{
	121	return q->nr_congestion_on;
	122	}
	123
	124	/*
	125	* The threshold at which a queue is considered to be uncongested
	126	*/
	127	static inline int queue_congestion_off_threshold(struct request_queue *q)
	128	{
	129	return q->nr_congestion_off;
	130	}
	131
7ba1ba12 MP	132	#if defined(CONFIG_BLK_DEV_INTEGRITY)
	133
	134	#define rq_for_each_integrity_segment(bvl, _rq, _iter) \
	135	__rq_for_each_bio(_iter.bio, _rq) \
	136	bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
	137
	138	#endif /* BLK_DEV_INTEGRITY */
	139
c7c22e4d JA	140	static inline int blk_cpu_to_group(int cpu)
	141	{
	142	#ifdef CONFIG_SCHED_MC
be4d638c RR	143	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be4d638c RR	144	return cpumask_first(mask);
c7c22e4d	145	#elif defined(CONFIG_SCHED_SMT)
c69fc56d	146	return cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	147	#else
	148	return cpu;
	149	#endif
	150	}
	151
c2553b58 JA	152	/*
	153	* Contribute to IO statistics IFF:
	154	*
	155	* a) it's attached to a gendisk, and
	156	* b) the queue had IO stats enabled when this request was started, and
	157	* c) it's a file system request
	158	*/
26308eab	159	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	160	{
c69d4854 JA	161	return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&
c69d4854 JA	162	blk_discard_rq(rq);
fb8ec18c JA	163	}
fb8ec18c JA	164
8324aa91	165	#endif