[linux.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;

static inline void __blk_get_queue(struct request_queue *q)
{
	kobject_get(&q->kobj);
}

int blk_init_rl(struct request_list *rl, struct request_queue *q,
		gfp_t gfp_mask);
void blk_exit_rl(struct request_list *rl);
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_queue_bypass_start(struct request_queue *q);
void blk_queue_bypass_end(struct request_queue *q);
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 *);

/*
 * 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) hash_hashed(&(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_dying(q)) ||
		    !q->elevator->type->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->type->ops.elevator_activate_req_fn)
		e->type->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->type->ops.elevator_deactivate_req_fn)
		e->type->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

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);
bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
int blk_try_merge(struct request *rq, struct bio *bio);

void blk_queue_congestion_threshold(struct request_queue *q);

void __blk_run_queue_uncond(struct request_queue *q);

int blk_dev_init(void);


/*
 * 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;
}

/*
 * 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 &&
	       (rq->cmd_flags & REQ_IO_STAT) &&
		(rq->cmd_type == REQ_TYPE_FS);
}

/*
 * Internal io_context interface
 */
void get_io_context(struct io_context *ioc);
struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
			     gfp_t gfp_mask);
void ioc_clear_queue(struct request_queue *q);

int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);

/**
 * create_io_context - try to create task->io_context
 * @gfp_mask: allocation mask
 * @node: allocation node
 *
 * If %current->io_context is %NULL, allocate a new io_context and install
 * it.  Returns the current %current->io_context which may be %NULL if
 * allocation failed.
 *
 * Note that this function can't be called with IRQ disabled because
 * task_lock which protects %current->io_context is IRQ-unsafe.
 */
static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
{
	WARN_ON_ONCE(irqs_disabled());
	if (unlikely(!current->io_context))
		create_task_io_context(current, gfp_mask, node);
	return current->io_context;
}

/*
 * Internal throttling interface
 */
#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);
#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) { }
#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
09ac46c4 TH	16	static inline void __blk_get_queue(struct request_queue *q)
	17	{
	18	kobject_get(&q->kobj);
	19	}
	20
5b788ce3 TH	21	int blk_init_rl(struct request_list rl, struct request_queue q,
	22	gfp_t gfp_mask);
	23	void blk_exit_rl(struct request_list *rl);
86db1e29 JA	24	void init_request_from_bio(struct request req, struct bio bio);
	25	void blk_rq_bio_prep(struct request_queue q, struct request rq,
	26	struct bio *bio);
a411f4bb BH	27	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	28	struct bio *bio);
d732580b TH	29	void blk_queue_bypass_start(struct request_queue *q);
d732580b TH	30	void blk_queue_bypass_end(struct request_queue *q);
9934c8c0	31	void blk_dequeue_request(struct request *rq);
8324aa91	32	void __blk_queue_free_tags(struct request_queue *q);
4853abaa JM	33	bool __blk_end_bidi_request(struct request *rq, int error,
4853abaa JM	34	unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91	35
242f9dcb JA	36	void blk_rq_timed_out_timer(unsigned long data);
	37	void blk_delete_timer(struct request *);
	38	void blk_add_timer(struct request *);
	39
	40	/*
	41	* Internal atomic flags for request handling
	42	*/
	43	enum rq_atomic_flags {
	44	REQ_ATOM_COMPLETE = 0,
	45	};
	46
	47	/*
	48	* EH timer and IO completion will both attempt to 'grab' the request, make
25985edc	49	* sure that only one of them succeeds
242f9dcb JA	50	*/
	51	static inline int blk_mark_rq_complete(struct request *rq)
	52	{
	53	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	54	}
	55
	56	static inline void blk_clear_rq_complete(struct request *rq)
	57	{
	58	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	59	}
86db1e29	60
158dbda0 TH	61	/*
	62	* Internal elevator interface
	63	*/
242d98f0	64	#define ELV_ON_HASH(rq) hash_hashed(&(rq)->hash)
158dbda0	65
ae1b1539 TH	66	void blk_insert_flush(struct request *rq);
ae1b1539 TH	67	void blk_abort_flushes(struct request_queue *q);
dd831006	68
158dbda0 TH	69	static inline struct request __elv_next_request(struct request_queue q)
	70	{
	71	struct request *rq;
	72
	73	while (1) {
ae1b1539	74	if (!list_empty(&q->queue_head)) {
158dbda0	75	rq = list_entry_rq(q->queue_head.next);
ae1b1539	76	return rq;
158dbda0 TH	77	}
158dbda0 TH	78
3ac0cc45	79	/*
	80	* Flush request is running and flush request isn't queueable
	81	* in the drive, we can hold the queue till flush request is
	82	* finished. Even we don't do this, driver can't dispatch next
	83	* requests and will requeue them. And this can improve
	84	* throughput too. For example, we have request flush1, write1,
	85	* flush 2. flush1 is dispatched, then queue is hold, write1
	86	* isn't inserted to queue. After flush1 is finished, flush2
	87	* will be dispatched. Since disk cache is already clean,
	88	* flush2 will be finished very soon, so looks like flush2 is
	89	* folded to flush1.
	90	* Since the queue is hold, a flag is set to indicate the queue
	91	* should be restarted later. Please see flush_end_io() for
	92	* details.
	93	*/
	94	if (q->flush_pending_idx != q->flush_running_idx &&
	95	!queue_flush_queueable(q)) {
	96	q->flush_queue_delayed = 1;
	97	return NULL;
	98	}
3f3299d5	99	if (unlikely(blk_queue_dying(q)) \|\|
22f746e2	100	!q->elevator->type->ops.elevator_dispatch_fn(q, 0))
158dbda0 TH	101	return NULL;
	102	}
	103	}
	104
	105	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	106	{
	107	struct elevator_queue *e = q->elevator;
	108
22f746e2 TH	109	if (e->type->ops.elevator_activate_req_fn)
22f746e2 TH	110	e->type->ops.elevator_activate_req_fn(q, rq);
158dbda0 TH	111	}
	112
	113	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	114	{
	115	struct elevator_queue *e = q->elevator;
	116
22f746e2 TH	117	if (e->type->ops.elevator_deactivate_req_fn)
22f746e2 TH	118	e->type->ops.elevator_deactivate_req_fn(q, rq);
158dbda0 TH	119	}
158dbda0 TH	120
581d4e28 JA	121	#ifdef CONFIG_FAIL_IO_TIMEOUT
	122	int blk_should_fake_timeout(struct request_queue *);
	123	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	124	ssize_t part_timeout_store(struct device , struct device_attribute ,
	125	const char *, size_t);
	126	#else
	127	static inline int blk_should_fake_timeout(struct request_queue *q)
	128	{
	129	return 0;
	130	}
	131	#endif
	132
d6d48196 JA	133	int ll_back_merge_fn(struct request_queue q, struct request req,
	134	struct bio *bio);
	135	int ll_front_merge_fn(struct request_queue q, struct request req,
	136	struct bio *bio);
	137	int attempt_back_merge(struct request_queue q, struct request rq);
	138	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	139	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	140	struct request *next);
d6d48196	141	void blk_recalc_rq_segments(struct request *rq);
80a761fd	142	void blk_rq_set_mixed_merge(struct request *rq);
050c8ea8 TH	143	bool blk_rq_merge_ok(struct request rq, struct bio bio);
050c8ea8 TH	144	int blk_try_merge(struct request rq, struct bio bio);
d6d48196	145
8324aa91 JA	146	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	147
c246e80d BVA	148	void __blk_run_queue_uncond(struct request_queue *q);
c246e80d BVA	149
ff88972c AB	150	int blk_dev_init(void);
ff88972c AB	151
f253b86b	152
8324aa91 JA	153	/*
	154	* Return the threshold (number of used requests) at which the queue is
	155	* considered to be congested. It include a little hysteresis to keep the
	156	* context switch rate down.
	157	*/
	158	static inline int queue_congestion_on_threshold(struct request_queue *q)
	159	{
	160	return q->nr_congestion_on;
	161	}
	162
	163	/*
	164	* The threshold at which a queue is considered to be uncongested
	165	*/
	166	static inline int queue_congestion_off_threshold(struct request_queue *q)
	167	{
	168	return q->nr_congestion_off;
	169	}
	170
c2553b58 JA	171	/*
	172	* Contribute to IO statistics IFF:
	173	*
	174	* a) it's attached to a gendisk, and
	175	* b) the queue had IO stats enabled when this request was started, and
e2a60da7	176	* c) it's a file system request
c2553b58	177	*/
26308eab	178	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	179	{
33659ebb CH	180	return rq->rq_disk &&
33659ebb CH	181	(rq->cmd_flags & REQ_IO_STAT) &&
e2a60da7	182	(rq->cmd_type == REQ_TYPE_FS);
fb8ec18c JA	183	}
fb8ec18c JA	184
f2dbd76a TH	185	/*
	186	* Internal io_context interface
	187	*/
	188	void get_io_context(struct io_context *ioc);
47fdd4ca	189	struct io_cq ioc_lookup_icq(struct io_context ioc, struct request_queue *q);
24acfc34 TH	190	struct io_cq ioc_create_icq(struct io_context ioc, struct request_queue *q,
24acfc34 TH	191	gfp_t gfp_mask);
7e5a8794	192	void ioc_clear_queue(struct request_queue *q);
f2dbd76a	193
24acfc34	194	int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
f2dbd76a TH	195
	196	/**
	197	* create_io_context - try to create task->io_context
f2dbd76a TH	198	* @gfp_mask: allocation mask
	199	* @node: allocation node
	200	*
24acfc34 TH	201	* If %current->io_context is %NULL, allocate a new io_context and install
	202	* it. Returns the current %current->io_context which may be %NULL if
	203	* allocation failed.
f2dbd76a TH	204	*
f2dbd76a TH	205	* Note that this function can't be called with IRQ disabled because
24acfc34	206	* task_lock which protects %current->io_context is IRQ-unsafe.
f2dbd76a	207	*/
24acfc34	208	static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
f2dbd76a TH	209	{
f2dbd76a TH	210	WARN_ON_ONCE(irqs_disabled());
24acfc34 TH	211	if (unlikely(!current->io_context))
	212	create_task_io_context(current, gfp_mask, node);
	213	return current->io_context;
f2dbd76a TH	214	}
	215
	216	/*
	217	* Internal throttling interface
	218	*/
bc9fcbf9	219	#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9	220	extern bool blk_throtl_bio(struct request_queue q, struct bio bio);
c9a929dd	221	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	222	extern int blk_throtl_init(struct request_queue *q);
	223	extern void blk_throtl_exit(struct request_queue *q);
	224	#else /* CONFIG_BLK_DEV_THROTTLING */
bc16a4f9	225	static inline bool blk_throtl_bio(struct request_queue q, struct bio bio)
bc9fcbf9	226	{
bc16a4f9	227	return false;
bc9fcbf9	228	}
c9a929dd	229	static inline void blk_throtl_drain(struct request_queue *q) { }
bc9fcbf9 TH	230	static inline int blk_throtl_init(struct request_queue *q) { return 0; }
	231	static inline void blk_throtl_exit(struct request_queue *q) { }
	232	#endif /* CONFIG_BLK_DEV_THROTTLING */
	233
	234	#endif /* BLK_INTERNAL_H */