[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_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);

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;
		}

		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);
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));
}

#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);
a411f4bb BH	16	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	17	struct bio *bio);
9934c8c0	18	void blk_dequeue_request(struct request *rq);
8324aa91 JA	19	void __blk_queue_free_tags(struct request_queue *q);
8324aa91 JA	20
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
25985edc	35	* sure that only one of them succeeds
242f9dcb JA	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
ae1b1539 TH	52	void blk_insert_flush(struct request *rq);
ae1b1539 TH	53	void blk_abort_flushes(struct request_queue *q);
dd831006	54
158dbda0 TH	55	static inline struct request __elv_next_request(struct request_queue q)
	56	{
	57	struct request *rq;
	58
	59	while (1) {
ae1b1539	60	if (!list_empty(&q->queue_head)) {
158dbda0	61	rq = list_entry_rq(q->queue_head.next);
ae1b1539	62	return rq;
158dbda0 TH	63	}
	64
	65	if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
	66	return NULL;
	67	}
	68	}
	69
	70	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	71	{
	72	struct elevator_queue *e = q->elevator;
	73
	74	if (e->ops->elevator_activate_req_fn)
	75	e->ops->elevator_activate_req_fn(q, rq);
	76	}
	77
	78	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	79	{
	80	struct elevator_queue *e = q->elevator;
	81
	82	if (e->ops->elevator_deactivate_req_fn)
	83	e->ops->elevator_deactivate_req_fn(q, rq);
	84	}
	85
581d4e28 JA	86	#ifdef CONFIG_FAIL_IO_TIMEOUT
	87	int blk_should_fake_timeout(struct request_queue *);
	88	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	89	ssize_t part_timeout_store(struct device , struct device_attribute ,
	90	const char *, size_t);
	91	#else
	92	static inline int blk_should_fake_timeout(struct request_queue *q)
	93	{
	94	return 0;
	95	}
	96	#endif
	97
86db1e29 JA	98	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	99
d6d48196 JA	100	int ll_back_merge_fn(struct request_queue q, struct request req,
	101	struct bio *bio);
	102	int ll_front_merge_fn(struct request_queue q, struct request req,
	103	struct bio *bio);
	104	int attempt_back_merge(struct request_queue q, struct request rq);
	105	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	106	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	107	struct request *next);
d6d48196	108	void blk_recalc_rq_segments(struct request *rq);
80a761fd	109	void blk_rq_set_mixed_merge(struct request *rq);
d6d48196	110
8324aa91 JA	111	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	112
ff88972c AB	113	int blk_dev_init(void);
ff88972c AB	114
f253b86b JA	115	void elv_quiesce_start(struct request_queue *q);
	116	void elv_quiesce_end(struct request_queue *q);
	117
	118
8324aa91 JA	119	/*
	120	* Return the threshold (number of used requests) at which the queue is
	121	* considered to be congested. It include a little hysteresis to keep the
	122	* context switch rate down.
	123	*/
	124	static inline int queue_congestion_on_threshold(struct request_queue *q)
	125	{
	126	return q->nr_congestion_on;
	127	}
	128
	129	/*
	130	* The threshold at which a queue is considered to be uncongested
	131	*/
	132	static inline int queue_congestion_off_threshold(struct request_queue *q)
	133	{
	134	return q->nr_congestion_off;
	135	}
	136
c7c22e4d JA	137	static inline int blk_cpu_to_group(int cpu)
c7c22e4d JA	138	{
be14eb61	139	int group = NR_CPUS;
c7c22e4d	140	#ifdef CONFIG_SCHED_MC
be4d638c	141	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be14eb61	142	group = cpumask_first(mask);
c7c22e4d	143	#elif defined(CONFIG_SCHED_SMT)
be14eb61	144	group = cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	145	#else
	146	return cpu;
	147	#endif
be14eb61 BK	148	if (likely(group < NR_CPUS))
	149	return group;
	150	return cpu;
c7c22e4d JA	151	}
c7c22e4d JA	152
c2553b58 JA	153	/*
	154	* Contribute to IO statistics IFF:
	155	*
	156	* a) it's attached to a gendisk, and
	157	* b) the queue had IO stats enabled when this request was started, and
3c4198e8	158	* c) it's a file system request or a discard request
c2553b58	159	*/
26308eab	160	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	161	{
33659ebb CH	162	return rq->rq_disk &&
	163	(rq->cmd_flags & REQ_IO_STAT) &&
	164	(rq->cmd_type == REQ_TYPE_FS \|\|
	165	(rq->cmd_flags & REQ_DISCARD));
fb8ec18c JA	166	}
fb8ec18c JA	167
8324aa91	168	#endif