[net-next-2.6.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_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))

struct request *blk_do_flush(struct request_queue *q, struct request *rq);

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 (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
			    rq == &q->flush_rq)
				return rq;
			rq = blk_do_flush(q, rq);
			if (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_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
86db1e29 JA	21	void blk_unplug_work(struct work_struct *work);
86db1e29 JA	22	void blk_unplug_timeout(unsigned long data);
242f9dcb JA	23	void blk_rq_timed_out_timer(unsigned long data);
	24	void blk_delete_timer(struct request *);
	25	void blk_add_timer(struct request *);
f73e2d13	26	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	27
	28	/*
	29	* Internal atomic flags for request handling
	30	*/
	31	enum rq_atomic_flags {
	32	REQ_ATOM_COMPLETE = 0,
	33	};
	34
	35	/*
	36	* EH timer and IO completion will both attempt to 'grab' the request, make
	37	* sure that only one of them suceeds
	38	*/
	39	static inline int blk_mark_rq_complete(struct request *rq)
	40	{
	41	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	42	}
	43
	44	static inline void blk_clear_rq_complete(struct request *rq)
	45	{
	46	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	47	}
86db1e29	48
158dbda0 TH	49	/*
	50	* Internal elevator interface
	51	*/
	52	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	53
dd4c133f	54	struct request blk_do_flush(struct request_queue q, struct request *rq);
dd831006	55
158dbda0 TH	56	static inline struct request __elv_next_request(struct request_queue q)
	57	{
	58	struct request *rq;
	59
	60	while (1) {
	61	while (!list_empty(&q->queue_head)) {
	62	rq = list_entry_rq(q->queue_head.next);
4fed947c TH	63	if (!(rq->cmd_flags & (REQ_FLUSH \| REQ_FUA)) \|\|
	64	rq == &q->flush_rq)
	65	return rq;
dd4c133f	66	rq = blk_do_flush(q, rq);
dd831006	67	if (rq)
158dbda0 TH	68	return rq;
	69	}
	70
	71	if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
	72	return NULL;
	73	}
	74	}
	75
	76	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	77	{
	78	struct elevator_queue *e = q->elevator;
	79
	80	if (e->ops->elevator_activate_req_fn)
	81	e->ops->elevator_activate_req_fn(q, rq);
	82	}
	83
	84	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	85	{
	86	struct elevator_queue *e = q->elevator;
	87
	88	if (e->ops->elevator_deactivate_req_fn)
	89	e->ops->elevator_deactivate_req_fn(q, rq);
	90	}
	91
581d4e28 JA	92	#ifdef CONFIG_FAIL_IO_TIMEOUT
	93	int blk_should_fake_timeout(struct request_queue *);
	94	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	95	ssize_t part_timeout_store(struct device , struct device_attribute ,
	96	const char *, size_t);
	97	#else
	98	static inline int blk_should_fake_timeout(struct request_queue *q)
	99	{
	100	return 0;
	101	}
	102	#endif
	103
86db1e29 JA	104	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	105
d6d48196 JA	106	int ll_back_merge_fn(struct request_queue q, struct request req,
	107	struct bio *bio);
	108	int ll_front_merge_fn(struct request_queue q, struct request req,
	109	struct bio *bio);
	110	int attempt_back_merge(struct request_queue q, struct request rq);
	111	int attempt_front_merge(struct request_queue q, struct request rq);
	112	void blk_recalc_rq_segments(struct request *rq);
80a761fd	113	void blk_rq_set_mixed_merge(struct request *rq);
d6d48196	114
8324aa91 JA	115	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	116
ff88972c AB	117	int blk_dev_init(void);
ff88972c AB	118
f253b86b JA	119	void elv_quiesce_start(struct request_queue *q);
	120	void elv_quiesce_end(struct request_queue *q);
	121
	122
8324aa91 JA	123	/*
	124	* Return the threshold (number of used requests) at which the queue is
	125	* considered to be congested. It include a little hysteresis to keep the
	126	* context switch rate down.
	127	*/
	128	static inline int queue_congestion_on_threshold(struct request_queue *q)
	129	{
	130	return q->nr_congestion_on;
	131	}
	132
	133	/*
	134	* The threshold at which a queue is considered to be uncongested
	135	*/
	136	static inline int queue_congestion_off_threshold(struct request_queue *q)
	137	{
	138	return q->nr_congestion_off;
	139	}
	140
c7c22e4d JA	141	static inline int blk_cpu_to_group(int cpu)
c7c22e4d JA	142	{
be14eb61	143	int group = NR_CPUS;
c7c22e4d	144	#ifdef CONFIG_SCHED_MC
be4d638c	145	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be14eb61	146	group = cpumask_first(mask);
c7c22e4d	147	#elif defined(CONFIG_SCHED_SMT)
be14eb61	148	group = cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	149	#else
	150	return cpu;
	151	#endif
be14eb61 BK	152	if (likely(group < NR_CPUS))
	153	return group;
	154	return cpu;
c7c22e4d JA	155	}
c7c22e4d JA	156
c2553b58 JA	157	/*
	158	* Contribute to IO statistics IFF:
	159	*
	160	* a) it's attached to a gendisk, and
	161	* b) the queue had IO stats enabled when this request was started, and
3c4198e8	162	* c) it's a file system request or a discard request
c2553b58	163	*/
26308eab	164	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	165	{
33659ebb CH	166	return rq->rq_disk &&
	167	(rq->cmd_flags & REQ_IO_STAT) &&
	168	(rq->cmd_type == REQ_TYPE_FS \|\|
	169	(rq->cmd_flags & REQ_DISCARD));
fb8ec18c JA	170	}
fb8ec18c JA	171
8324aa91	172	#endif