[linux-block.git] / block / blk.h

#ifndef BLK_INTERNAL_H
#define BLK_INTERNAL_H

#include <linux/idr.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;
extern struct ida blk_queue_ida;

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 (unlikely(blk_queue_dead(q)) ||
		    !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

void get_io_context(struct io_context *ioc);
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
a73f730d TH	4	#include <linux/idr.h>
a73f730d TH	5
86db1e29 JA	6	/* Amount of time in which a process may batch requests */
	7	#define BLK_BATCH_TIME (HZ/50UL)
	8
	9	/* Number of requests a "batching" process may submit */
	10	#define BLK_BATCH_REQ 32
	11
8324aa91 JA	12	extern struct kmem_cache *blk_requestq_cachep;
8324aa91 JA	13	extern struct kobj_type blk_queue_ktype;
a73f730d	14	extern struct ida blk_queue_ida;
8324aa91	15
86db1e29 JA	16	void init_request_from_bio(struct request req, struct bio bio);
	17	void blk_rq_bio_prep(struct request_queue q, struct request rq,
	18	struct bio *bio);
a411f4bb BH	19	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	20	struct bio *bio);
c9a929dd	21	void blk_drain_queue(struct request_queue *q, bool drain_all);
9934c8c0	22	void blk_dequeue_request(struct request *rq);
8324aa91	23	void __blk_queue_free_tags(struct request_queue *q);
4853abaa JM	24	bool __blk_end_bidi_request(struct request *rq, int error,
4853abaa JM	25	unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91	26
242f9dcb JA	27	void blk_rq_timed_out_timer(unsigned long data);
	28	void blk_delete_timer(struct request *);
	29	void blk_add_timer(struct request *);
f73e2d13	30	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	31
	32	/*
	33	* Internal atomic flags for request handling
	34	*/
	35	enum rq_atomic_flags {
	36	REQ_ATOM_COMPLETE = 0,
	37	};
	38
	39	/*
	40	* EH timer and IO completion will both attempt to 'grab' the request, make
25985edc	41	* sure that only one of them succeeds
242f9dcb JA	42	*/
	43	static inline int blk_mark_rq_complete(struct request *rq)
	44	{
	45	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	46	}
	47
	48	static inline void blk_clear_rq_complete(struct request *rq)
	49	{
	50	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	51	}
86db1e29	52
158dbda0 TH	53	/*
	54	* Internal elevator interface
	55	*/
	56	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	57
ae1b1539 TH	58	void blk_insert_flush(struct request *rq);
ae1b1539 TH	59	void blk_abort_flushes(struct request_queue *q);
dd831006	60
158dbda0 TH	61	static inline struct request __elv_next_request(struct request_queue q)
	62	{
	63	struct request *rq;
	64
	65	while (1) {
ae1b1539	66	if (!list_empty(&q->queue_head)) {
158dbda0	67	rq = list_entry_rq(q->queue_head.next);
ae1b1539	68	return rq;
158dbda0 TH	69	}
158dbda0 TH	70
3ac0cc45	71	/*
	72	* Flush request is running and flush request isn't queueable
	73	* in the drive, we can hold the queue till flush request is
	74	* finished. Even we don't do this, driver can't dispatch next
	75	* requests and will requeue them. And this can improve
	76	* throughput too. For example, we have request flush1, write1,
	77	* flush 2. flush1 is dispatched, then queue is hold, write1
	78	* isn't inserted to queue. After flush1 is finished, flush2
	79	* will be dispatched. Since disk cache is already clean,
	80	* flush2 will be finished very soon, so looks like flush2 is
	81	* folded to flush1.
	82	* Since the queue is hold, a flag is set to indicate the queue
	83	* should be restarted later. Please see flush_end_io() for
	84	* details.
	85	*/
	86	if (q->flush_pending_idx != q->flush_running_idx &&
	87	!queue_flush_queueable(q)) {
	88	q->flush_queue_delayed = 1;
	89	return NULL;
	90	}
34f6055c	91	if (unlikely(blk_queue_dead(q)) \|\|
0a58e077	92	!q->elevator->ops->elevator_dispatch_fn(q, 0))
158dbda0 TH	93	return NULL;
	94	}
	95	}
	96
	97	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	98	{
	99	struct elevator_queue *e = q->elevator;
	100
	101	if (e->ops->elevator_activate_req_fn)
	102	e->ops->elevator_activate_req_fn(q, rq);
	103	}
	104
	105	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	106	{
	107	struct elevator_queue *e = q->elevator;
	108
	109	if (e->ops->elevator_deactivate_req_fn)
	110	e->ops->elevator_deactivate_req_fn(q, rq);
	111	}
	112
581d4e28 JA	113	#ifdef CONFIG_FAIL_IO_TIMEOUT
	114	int blk_should_fake_timeout(struct request_queue *);
	115	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	116	ssize_t part_timeout_store(struct device , struct device_attribute ,
	117	const char *, size_t);
	118	#else
	119	static inline int blk_should_fake_timeout(struct request_queue *q)
	120	{
	121	return 0;
	122	}
	123	#endif
	124
6e736be7	125	void get_io_context(struct io_context *ioc);
86db1e29 JA	126	struct io_context *current_io_context(gfp_t gfp_flags, int node);
86db1e29 JA	127
d6d48196 JA	128	int ll_back_merge_fn(struct request_queue q, struct request req,
	129	struct bio *bio);
	130	int ll_front_merge_fn(struct request_queue q, struct request req,
	131	struct bio *bio);
	132	int attempt_back_merge(struct request_queue q, struct request rq);
	133	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	134	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	135	struct request *next);
d6d48196	136	void blk_recalc_rq_segments(struct request *rq);
80a761fd	137	void blk_rq_set_mixed_merge(struct request *rq);
d6d48196	138
8324aa91 JA	139	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	140
ff88972c AB	141	int blk_dev_init(void);
ff88972c AB	142
f253b86b JA	143	void elv_quiesce_start(struct request_queue *q);
	144	void elv_quiesce_end(struct request_queue *q);
	145
	146
8324aa91 JA	147	/*
	148	* Return the threshold (number of used requests) at which the queue is
	149	* considered to be congested. It include a little hysteresis to keep the
	150	* context switch rate down.
	151	*/
	152	static inline int queue_congestion_on_threshold(struct request_queue *q)
	153	{
	154	return q->nr_congestion_on;
	155	}
	156
	157	/*
	158	* The threshold at which a queue is considered to be uncongested
	159	*/
	160	static inline int queue_congestion_off_threshold(struct request_queue *q)
	161	{
	162	return q->nr_congestion_off;
	163	}
	164
c7c22e4d JA	165	static inline int blk_cpu_to_group(int cpu)
c7c22e4d JA	166	{
be14eb61	167	int group = NR_CPUS;
c7c22e4d	168	#ifdef CONFIG_SCHED_MC
be4d638c	169	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be14eb61	170	group = cpumask_first(mask);
c7c22e4d	171	#elif defined(CONFIG_SCHED_SMT)
be14eb61	172	group = cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	173	#else
	174	return cpu;
	175	#endif
be14eb61 BK	176	if (likely(group < NR_CPUS))
	177	return group;
	178	return cpu;
c7c22e4d JA	179	}
c7c22e4d JA	180
c2553b58 JA	181	/*
	182	* Contribute to IO statistics IFF:
	183	*
	184	* a) it's attached to a gendisk, and
	185	* b) the queue had IO stats enabled when this request was started, and
3c4198e8	186	* c) it's a file system request or a discard request
c2553b58	187	*/
26308eab	188	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	189	{
33659ebb CH	190	return rq->rq_disk &&
	191	(rq->cmd_flags & REQ_IO_STAT) &&
	192	(rq->cmd_type == REQ_TYPE_FS \|\|
	193	(rq->cmd_flags & REQ_DISCARD));
fb8ec18c JA	194	}
fb8ec18c JA	195
bc9fcbf9	196	#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9	197	extern bool blk_throtl_bio(struct request_queue q, struct bio bio);
c9a929dd	198	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	199	extern int blk_throtl_init(struct request_queue *q);
bc9fcbf9 TH	200	extern void blk_throtl_exit(struct request_queue *q);
c9a929dd	201	extern void blk_throtl_release(struct request_queue *q);
bc9fcbf9	202	#else /* CONFIG_BLK_DEV_THROTTLING */
bc16a4f9	203	static inline bool blk_throtl_bio(struct request_queue q, struct bio bio)
bc9fcbf9	204	{
bc16a4f9	205	return false;
bc9fcbf9	206	}
c9a929dd	207	static inline void blk_throtl_drain(struct request_queue *q) { }
bc9fcbf9 TH	208	static inline int blk_throtl_init(struct request_queue *q) { return 0; }
bc9fcbf9 TH	209	static inline void blk_throtl_exit(struct request_queue *q) { }
c9a929dd	210	static inline void blk_throtl_release(struct request_queue *q) { }
bc9fcbf9 TH	211	#endif /* CONFIG_BLK_DEV_THROTTLING */
	212
	213	#endif /* BLK_INTERNAL_H */