[thirdparty/kernel/stable.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 kmem_cache *request_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_rq_check_expired(struct request *rq, unsigned long *next_timeout,
			  unsigned int *next_set);
void blk_add_timer(struct request *req);
void blk_delete_timer(struct request *);


bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
			     struct bio *bio);
bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
			    struct bio *bio);
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
			    unsigned int *request_count);

void blk_account_io_start(struct request *req, bool new_io);
void blk_account_io_completion(struct request *req, unsigned int bytes);
void blk_account_io_done(struct request *req);

/*
 * Internal atomic flags for request handling
 */
enum rq_atomic_flags {
	REQ_ATOM_COMPLETE = 0,
	REQ_ATOM_STARTED,
};

/*
 * 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) ((rq)->cmd_flags & REQ_HASHED)

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_bypass(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	12	extern struct kmem_cache *blk_requestq_cachep;
320ae51f	13	extern struct kmem_cache *request_cachep;
8324aa91	14	extern struct kobj_type blk_queue_ktype;
a73f730d	15	extern struct ida blk_queue_ida;
8324aa91	16
09ac46c4 TH	17	static inline void __blk_get_queue(struct request_queue *q)
	18	{
	19	kobject_get(&q->kobj);
	20	}
	21
5b788ce3 TH	22	int blk_init_rl(struct request_list rl, struct request_queue q,
	23	gfp_t gfp_mask);
	24	void blk_exit_rl(struct request_list *rl);
86db1e29 JA	25	void init_request_from_bio(struct request req, struct bio bio);
	26	void blk_rq_bio_prep(struct request_queue q, struct request rq,
	27	struct bio *bio);
a411f4bb BH	28	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	29	struct bio *bio);
d732580b TH	30	void blk_queue_bypass_start(struct request_queue *q);
d732580b TH	31	void blk_queue_bypass_end(struct request_queue *q);
9934c8c0	32	void blk_dequeue_request(struct request *rq);
8324aa91	33	void __blk_queue_free_tags(struct request_queue *q);
4853abaa JM	34	bool __blk_end_bidi_request(struct request *rq, int error,
4853abaa JM	35	unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91	36
242f9dcb	37	void blk_rq_timed_out_timer(unsigned long data);
320ae51f JA	38	void blk_rq_check_expired(struct request rq, unsigned long next_timeout,
320ae51f JA	39	unsigned int *next_set);
87ee7b11	40	void blk_add_timer(struct request *req);
242f9dcb	41	void blk_delete_timer(struct request *);
242f9dcb	42
320ae51f JA	43
	44	bool bio_attempt_front_merge(struct request_queue q, struct request req,
	45	struct bio *bio);
	46	bool bio_attempt_back_merge(struct request_queue q, struct request req,
	47	struct bio *bio);
	48	bool blk_attempt_plug_merge(struct request_queue q, struct bio bio,
	49	unsigned int *request_count);
	50
	51	void blk_account_io_start(struct request *req, bool new_io);
	52	void blk_account_io_completion(struct request *req, unsigned int bytes);
	53	void blk_account_io_done(struct request *req);
	54
242f9dcb JA	55	/*
	56	* Internal atomic flags for request handling
	57	*/
	58	enum rq_atomic_flags {
	59	REQ_ATOM_COMPLETE = 0,
320ae51f	60	REQ_ATOM_STARTED,
242f9dcb JA	61	};
	62
	63	/*
	64	* EH timer and IO completion will both attempt to 'grab' the request, make
25985edc	65	* sure that only one of them succeeds
242f9dcb JA	66	*/
	67	static inline int blk_mark_rq_complete(struct request *rq)
	68	{
	69	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	70	}
	71
	72	static inline void blk_clear_rq_complete(struct request *rq)
	73	{
	74	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	75	}
86db1e29	76
158dbda0 TH	77	/*
	78	* Internal elevator interface
	79	*/
360f92c2	80	#define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
158dbda0	81
ae1b1539 TH	82	void blk_insert_flush(struct request *rq);
ae1b1539 TH	83	void blk_abort_flushes(struct request_queue *q);
dd831006	84
158dbda0 TH	85	static inline struct request __elv_next_request(struct request_queue q)
	86	{
	87	struct request *rq;
	88
	89	while (1) {
ae1b1539	90	if (!list_empty(&q->queue_head)) {
158dbda0	91	rq = list_entry_rq(q->queue_head.next);
ae1b1539	92	return rq;
158dbda0 TH	93	}
158dbda0 TH	94
3ac0cc45	95	/*
	96	* Flush request is running and flush request isn't queueable
	97	* in the drive, we can hold the queue till flush request is
	98	* finished. Even we don't do this, driver can't dispatch next
	99	* requests and will requeue them. And this can improve
	100	* throughput too. For example, we have request flush1, write1,
	101	* flush 2. flush1 is dispatched, then queue is hold, write1
	102	* isn't inserted to queue. After flush1 is finished, flush2
	103	* will be dispatched. Since disk cache is already clean,
	104	* flush2 will be finished very soon, so looks like flush2 is
	105	* folded to flush1.
	106	* Since the queue is hold, a flag is set to indicate the queue
	107	* should be restarted later. Please see flush_end_io() for
	108	* details.
	109	*/
	110	if (q->flush_pending_idx != q->flush_running_idx &&
	111	!queue_flush_queueable(q)) {
	112	q->flush_queue_delayed = 1;
	113	return NULL;
	114	}
556ee818	115	if (unlikely(blk_queue_bypass(q)) \|\|
22f746e2	116	!q->elevator->type->ops.elevator_dispatch_fn(q, 0))
158dbda0 TH	117	return NULL;
	118	}
	119	}
	120
	121	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	122	{
	123	struct elevator_queue *e = q->elevator;
	124
22f746e2 TH	125	if (e->type->ops.elevator_activate_req_fn)
22f746e2 TH	126	e->type->ops.elevator_activate_req_fn(q, rq);
158dbda0 TH	127	}
	128
	129	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	130	{
	131	struct elevator_queue *e = q->elevator;
	132
22f746e2 TH	133	if (e->type->ops.elevator_deactivate_req_fn)
22f746e2 TH	134	e->type->ops.elevator_deactivate_req_fn(q, rq);
158dbda0 TH	135	}
158dbda0 TH	136
581d4e28 JA	137	#ifdef CONFIG_FAIL_IO_TIMEOUT
	138	int blk_should_fake_timeout(struct request_queue *);
	139	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	140	ssize_t part_timeout_store(struct device , struct device_attribute ,
	141	const char *, size_t);
	142	#else
	143	static inline int blk_should_fake_timeout(struct request_queue *q)
	144	{
	145	return 0;
	146	}
	147	#endif
	148
d6d48196 JA	149	int ll_back_merge_fn(struct request_queue q, struct request req,
	150	struct bio *bio);
	151	int ll_front_merge_fn(struct request_queue q, struct request req,
	152	struct bio *bio);
	153	int attempt_back_merge(struct request_queue q, struct request rq);
	154	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	155	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	156	struct request *next);
d6d48196	157	void blk_recalc_rq_segments(struct request *rq);
80a761fd	158	void blk_rq_set_mixed_merge(struct request *rq);
050c8ea8 TH	159	bool blk_rq_merge_ok(struct request rq, struct bio bio);
050c8ea8 TH	160	int blk_try_merge(struct request rq, struct bio bio);
d6d48196	161
8324aa91 JA	162	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	163
c246e80d BVA	164	void __blk_run_queue_uncond(struct request_queue *q);
c246e80d BVA	165
ff88972c AB	166	int blk_dev_init(void);
ff88972c AB	167
f253b86b	168
8324aa91 JA	169	/*
	170	* Return the threshold (number of used requests) at which the queue is
	171	* considered to be congested. It include a little hysteresis to keep the
	172	* context switch rate down.
	173	*/
	174	static inline int queue_congestion_on_threshold(struct request_queue *q)
	175	{
	176	return q->nr_congestion_on;
	177	}
	178
	179	/*
	180	* The threshold at which a queue is considered to be uncongested
	181	*/
	182	static inline int queue_congestion_off_threshold(struct request_queue *q)
	183	{
	184	return q->nr_congestion_off;
	185	}
	186
c2553b58 JA	187	/*
	188	* Contribute to IO statistics IFF:
	189	*
	190	* a) it's attached to a gendisk, and
	191	* b) the queue had IO stats enabled when this request was started, and
e2a60da7	192	* c) it's a file system request
c2553b58	193	*/
26308eab	194	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	195	{
33659ebb CH	196	return rq->rq_disk &&
33659ebb CH	197	(rq->cmd_flags & REQ_IO_STAT) &&
e2a60da7	198	(rq->cmd_type == REQ_TYPE_FS);
fb8ec18c JA	199	}
fb8ec18c JA	200
f2dbd76a TH	201	/*
	202	* Internal io_context interface
	203	*/
	204	void get_io_context(struct io_context *ioc);
47fdd4ca	205	struct io_cq ioc_lookup_icq(struct io_context ioc, struct request_queue *q);
24acfc34 TH	206	struct io_cq ioc_create_icq(struct io_context ioc, struct request_queue *q,
24acfc34 TH	207	gfp_t gfp_mask);
7e5a8794	208	void ioc_clear_queue(struct request_queue *q);
f2dbd76a	209
24acfc34	210	int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
f2dbd76a TH	211
	212	/**
	213	* create_io_context - try to create task->io_context
f2dbd76a TH	214	* @gfp_mask: allocation mask
	215	* @node: allocation node
	216	*
24acfc34 TH	217	* If %current->io_context is %NULL, allocate a new io_context and install
	218	* it. Returns the current %current->io_context which may be %NULL if
	219	* allocation failed.
f2dbd76a TH	220	*
f2dbd76a TH	221	* Note that this function can't be called with IRQ disabled because
24acfc34	222	* task_lock which protects %current->io_context is IRQ-unsafe.
f2dbd76a	223	*/
24acfc34	224	static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
f2dbd76a TH	225	{
f2dbd76a TH	226	WARN_ON_ONCE(irqs_disabled());
24acfc34 TH	227	if (unlikely(!current->io_context))
	228	create_task_io_context(current, gfp_mask, node);
	229	return current->io_context;
f2dbd76a TH	230	}
	231
	232	/*
	233	* Internal throttling interface
	234	*/
bc9fcbf9	235	#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9	236	extern bool blk_throtl_bio(struct request_queue q, struct bio bio);
c9a929dd	237	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	238	extern int blk_throtl_init(struct request_queue *q);
	239	extern void blk_throtl_exit(struct request_queue *q);
	240	#else /* CONFIG_BLK_DEV_THROTTLING */
bc16a4f9	241	static inline bool blk_throtl_bio(struct request_queue q, struct bio bio)
bc9fcbf9	242	{
bc16a4f9	243	return false;
bc9fcbf9	244	}
c9a929dd	245	static inline void blk_throtl_drain(struct request_queue *q) { }
bc9fcbf9 TH	246	static inline int blk_throtl_init(struct request_queue *q) { return 0; }
	247	static inline void blk_throtl_exit(struct request_queue *q) { }
	248	#endif /* CONFIG_BLK_DEV_THROTTLING */
	249
	250	#endif /* BLK_INTERNAL_H */