[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);
}

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->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);

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));
}

/*
 * 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 request_queue *q, gfp_t gfp_mask);
void ioc_clear_queue(struct request_queue *q);

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

/**
 * create_io_context - try to create task->io_context
 * @task: target task
 * @gfp_mask: allocation mask
 * @node: allocation node
 *
 * If @task->io_context is %NULL, allocate a new io_context and install it.
 * Returns the current @task->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 @task->io_context is IRQ-unsafe.
 */
static inline struct io_context *create_io_context(struct task_struct *task,
						   gfp_t gfp_mask, int node)
{
	WARN_ON_ONCE(irqs_disabled());
	if (unlikely(!task->io_context))
		create_io_context_slowpath(task, gfp_mask, node);
	return task->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);
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
09ac46c4 TH	16	static inline void __blk_get_queue(struct request_queue *q)
	17	{
	18	kobject_get(&q->kobj);
	19	}
	20
86db1e29 JA	21	void init_request_from_bio(struct request req, struct bio bio);
	22	void blk_rq_bio_prep(struct request_queue q, struct request rq,
	23	struct bio *bio);
a411f4bb BH	24	int blk_rq_append_bio(struct request_queue q, struct request rq,
a411f4bb BH	25	struct bio *bio);
c9a929dd	26	void blk_drain_queue(struct request_queue *q, bool drain_all);
9934c8c0	27	void blk_dequeue_request(struct request *rq);
8324aa91	28	void __blk_queue_free_tags(struct request_queue *q);
4853abaa JM	29	bool __blk_end_bidi_request(struct request *rq, int error,
4853abaa JM	30	unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91	31
242f9dcb JA	32	void blk_rq_timed_out_timer(unsigned long data);
	33	void blk_delete_timer(struct request *);
	34	void blk_add_timer(struct request *);
f73e2d13	35	void __generic_unplug_device(struct request_queue *);
242f9dcb JA	36
	37	/*
	38	* Internal atomic flags for request handling
	39	*/
	40	enum rq_atomic_flags {
	41	REQ_ATOM_COMPLETE = 0,
	42	};
	43
	44	/*
	45	* EH timer and IO completion will both attempt to 'grab' the request, make
25985edc	46	* sure that only one of them succeeds
242f9dcb JA	47	*/
	48	static inline int blk_mark_rq_complete(struct request *rq)
	49	{
	50	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	51	}
	52
	53	static inline void blk_clear_rq_complete(struct request *rq)
	54	{
	55	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
	56	}
86db1e29	57
158dbda0 TH	58	/*
	59	* Internal elevator interface
	60	*/
	61	#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
	62
ae1b1539 TH	63	void blk_insert_flush(struct request *rq);
ae1b1539 TH	64	void blk_abort_flushes(struct request_queue *q);
dd831006	65
158dbda0 TH	66	static inline struct request __elv_next_request(struct request_queue q)
	67	{
	68	struct request *rq;
	69
	70	while (1) {
ae1b1539	71	if (!list_empty(&q->queue_head)) {
158dbda0	72	rq = list_entry_rq(q->queue_head.next);
ae1b1539	73	return rq;
158dbda0 TH	74	}
158dbda0 TH	75
3ac0cc45	76	/*
	77	* Flush request is running and flush request isn't queueable
	78	* in the drive, we can hold the queue till flush request is
	79	* finished. Even we don't do this, driver can't dispatch next
	80	* requests and will requeue them. And this can improve
	81	* throughput too. For example, we have request flush1, write1,
	82	* flush 2. flush1 is dispatched, then queue is hold, write1
	83	* isn't inserted to queue. After flush1 is finished, flush2
	84	* will be dispatched. Since disk cache is already clean,
	85	* flush2 will be finished very soon, so looks like flush2 is
	86	* folded to flush1.
	87	* Since the queue is hold, a flag is set to indicate the queue
	88	* should be restarted later. Please see flush_end_io() for
	89	* details.
	90	*/
	91	if (q->flush_pending_idx != q->flush_running_idx &&
	92	!queue_flush_queueable(q)) {
	93	q->flush_queue_delayed = 1;
	94	return NULL;
	95	}
34f6055c	96	if (unlikely(blk_queue_dead(q)) \|\|
22f746e2	97	!q->elevator->type->ops.elevator_dispatch_fn(q, 0))
158dbda0 TH	98	return NULL;
	99	}
	100	}
	101
	102	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	103	{
	104	struct elevator_queue *e = q->elevator;
	105
22f746e2 TH	106	if (e->type->ops.elevator_activate_req_fn)
22f746e2 TH	107	e->type->ops.elevator_activate_req_fn(q, rq);
158dbda0 TH	108	}
	109
	110	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	111	{
	112	struct elevator_queue *e = q->elevator;
	113
22f746e2 TH	114	if (e->type->ops.elevator_deactivate_req_fn)
22f746e2 TH	115	e->type->ops.elevator_deactivate_req_fn(q, rq);
158dbda0 TH	116	}
158dbda0 TH	117
581d4e28 JA	118	#ifdef CONFIG_FAIL_IO_TIMEOUT
	119	int blk_should_fake_timeout(struct request_queue *);
	120	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	121	ssize_t part_timeout_store(struct device , struct device_attribute ,
	122	const char *, size_t);
	123	#else
	124	static inline int blk_should_fake_timeout(struct request_queue *q)
	125	{
	126	return 0;
	127	}
	128	#endif
	129
d6d48196 JA	130	int ll_back_merge_fn(struct request_queue q, struct request req,
	131	struct bio *bio);
	132	int ll_front_merge_fn(struct request_queue q, struct request req,
	133	struct bio *bio);
	134	int attempt_back_merge(struct request_queue q, struct request rq);
	135	int attempt_front_merge(struct request_queue q, struct request rq);
5e84ea3a JA	136	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	137	struct request *next);
d6d48196	138	void blk_recalc_rq_segments(struct request *rq);
80a761fd	139	void blk_rq_set_mixed_merge(struct request *rq);
d6d48196	140
8324aa91 JA	141	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	142
ff88972c AB	143	int blk_dev_init(void);
ff88972c AB	144
f253b86b JA	145	void elv_quiesce_start(struct request_queue *q);
	146	void elv_quiesce_end(struct request_queue *q);
	147
	148
8324aa91 JA	149	/*
	150	* Return the threshold (number of used requests) at which the queue is
	151	* considered to be congested. It include a little hysteresis to keep the
	152	* context switch rate down.
	153	*/
	154	static inline int queue_congestion_on_threshold(struct request_queue *q)
	155	{
	156	return q->nr_congestion_on;
	157	}
	158
	159	/*
	160	* The threshold at which a queue is considered to be uncongested
	161	*/
	162	static inline int queue_congestion_off_threshold(struct request_queue *q)
	163	{
	164	return q->nr_congestion_off;
	165	}
	166
c7c22e4d JA	167	static inline int blk_cpu_to_group(int cpu)
c7c22e4d JA	168	{
be14eb61	169	int group = NR_CPUS;
c7c22e4d	170	#ifdef CONFIG_SCHED_MC
be4d638c	171	const struct cpumask *mask = cpu_coregroup_mask(cpu);
be14eb61	172	group = cpumask_first(mask);
c7c22e4d	173	#elif defined(CONFIG_SCHED_SMT)
be14eb61	174	group = cpumask_first(topology_thread_cpumask(cpu));
c7c22e4d JA	175	#else
	176	return cpu;
	177	#endif
be14eb61 BK	178	if (likely(group < NR_CPUS))
	179	return group;
	180	return cpu;
c7c22e4d JA	181	}
c7c22e4d JA	182
c2553b58 JA	183	/*
	184	* Contribute to IO statistics IFF:
	185	*
	186	* a) it's attached to a gendisk, and
	187	* b) the queue had IO stats enabled when this request was started, and
3c4198e8	188	* c) it's a file system request or a discard request
c2553b58	189	*/
26308eab	190	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	191	{
33659ebb CH	192	return rq->rq_disk &&
	193	(rq->cmd_flags & REQ_IO_STAT) &&
	194	(rq->cmd_type == REQ_TYPE_FS \|\|
	195	(rq->cmd_flags & REQ_DISCARD));
fb8ec18c JA	196	}
fb8ec18c JA	197
f2dbd76a TH	198	/*
	199	* Internal io_context interface
	200	*/
	201	void get_io_context(struct io_context *ioc);
47fdd4ca	202	struct io_cq ioc_lookup_icq(struct io_context ioc, struct request_queue *q);
f1f8cc94	203	struct io_cq ioc_create_icq(struct request_queue q, gfp_t gfp_mask);
7e5a8794	204	void ioc_clear_queue(struct request_queue *q);
f2dbd76a TH	205
	206	void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
	207	int node);
	208
	209	/**
	210	* create_io_context - try to create task->io_context
	211	* @task: target task
	212	* @gfp_mask: allocation mask
	213	* @node: allocation node
	214	*
	215	* If @task->io_context is %NULL, allocate a new io_context and install it.
	216	* Returns the current @task->io_context which may be %NULL if allocation
	217	* failed.
	218	*
	219	* Note that this function can't be called with IRQ disabled because
	220	* task_lock which protects @task->io_context is IRQ-unsafe.
	221	*/
	222	static inline struct io_context create_io_context(struct task_struct task,
	223	gfp_t gfp_mask, int node)
	224	{
	225	WARN_ON_ONCE(irqs_disabled());
	226	if (unlikely(!task->io_context))
	227	create_io_context_slowpath(task, gfp_mask, node);
	228	return task->io_context;
	229	}
	230
	231	/*
	232	* Internal throttling interface
	233	*/
bc9fcbf9	234	#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9	235	extern bool blk_throtl_bio(struct request_queue q, struct bio bio);
c9a929dd	236	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	237	extern int blk_throtl_init(struct request_queue *q);
bc9fcbf9 TH	238	extern void blk_throtl_exit(struct request_queue *q);
c9a929dd	239	extern void blk_throtl_release(struct request_queue *q);
bc9fcbf9	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; }
bc9fcbf9 TH	247	static inline void blk_throtl_exit(struct request_queue *q) { }
c9a929dd	248	static inline void blk_throtl_release(struct request_queue *q) { }
bc9fcbf9 TH	249	#endif /* CONFIG_BLK_DEV_THROTTLING */
	250
	251	#endif /* BLK_INTERNAL_H */