[linux-2.6-block.git] / block / blk.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BLK_INTERNAL_H
#define BLK_INTERNAL_H

#include <linux/idr.h>
#include <linux/blk-mq.h>
#include "blk-mq.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

/* Max future timer expiry for timeouts */
#define BLK_MAX_TIMEOUT		(5 * HZ)

#ifdef CONFIG_DEBUG_FS
extern struct dentry *blk_debugfs_root;
#endif

struct blk_flush_queue {
	unsigned int		flush_queue_delayed:1;
	unsigned int		flush_pending_idx:1;
	unsigned int		flush_running_idx:1;
	unsigned long		flush_pending_since;
	struct list_head	flush_queue[2];
	struct list_head	flush_data_in_flight;
	struct request		*flush_rq;

	/*
	 * flush_rq shares tag with this rq, both can't be active
	 * at the same time
	 */
	struct request		*orig_rq;
	spinlock_t		mq_flush_lock;
};

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;

/*
 * @q->queue_lock is set while a queue is being initialized. Since we know
 * that no other threads access the queue object before @q->queue_lock has
 * been set, it is safe to manipulate queue flags without holding the
 * queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and
 * blk_init_allocated_queue().
 */
static inline void queue_lockdep_assert_held(struct request_queue *q)
{
	if (q->queue_lock)
		lockdep_assert_held(q->queue_lock);
}

static inline void queue_flag_set_unlocked(unsigned int flag,
					   struct request_queue *q)
{
	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
	    kref_read(&q->kobj.kref))
		lockdep_assert_held(q->queue_lock);
	__set_bit(flag, &q->queue_flags);
}

static inline void queue_flag_clear_unlocked(unsigned int flag,
					     struct request_queue *q)
{
	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
	    kref_read(&q->kobj.kref))
		lockdep_assert_held(q->queue_lock);
	__clear_bit(flag, &q->queue_flags);
}

static inline int queue_flag_test_and_clear(unsigned int flag,
					    struct request_queue *q)
{
	queue_lockdep_assert_held(q);

	if (test_bit(flag, &q->queue_flags)) {
		__clear_bit(flag, &q->queue_flags);
		return 1;
	}

	return 0;
}

static inline int queue_flag_test_and_set(unsigned int flag,
					  struct request_queue *q)
{
	queue_lockdep_assert_held(q);

	if (!test_bit(flag, &q->queue_flags)) {
		__set_bit(flag, &q->queue_flags);
		return 0;
	}

	return 1;
}

static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
{
	queue_lockdep_assert_held(q);
	__set_bit(flag, &q->queue_flags);
}

static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
{
	queue_lockdep_assert_held(q);
	__clear_bit(flag, &q->queue_flags);
}

static inline struct blk_flush_queue *blk_get_flush_queue(
		struct request_queue *q, struct blk_mq_ctx *ctx)
{
	if (q->mq_ops)
		return blk_mq_map_queue(q, ctx->cpu)->fq;
	return q->fq;
}

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

struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
		int node, int cmd_size);
void blk_free_flush_queue(struct blk_flush_queue *q);

int blk_init_rl(struct request_list *rl, struct request_queue *q,
		gfp_t gfp_mask);
void blk_exit_rl(struct request_queue *q, struct request_list *rl);
void blk_rq_bio_prep(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_queue_free_tags(struct request_queue *q);
void blk_freeze_queue(struct request_queue *q);

static inline void blk_queue_enter_live(struct request_queue *q)
{
	/*
	 * Given that running in generic_make_request() context
	 * guarantees that a live reference against q_usage_counter has
	 * been established, further references under that same context
	 * need not check that the queue has been frozen (marked dead).
	 */
	percpu_ref_get(&q->q_usage_counter);
}

#ifdef CONFIG_BLK_DEV_INTEGRITY
void blk_flush_integrity(void);
bool __bio_integrity_endio(struct bio *);
static inline bool bio_integrity_endio(struct bio *bio)
{
	if (bio_integrity(bio))
		return __bio_integrity_endio(bio);
	return true;
}
#else
static inline void blk_flush_integrity(void)
{
}
static inline bool bio_integrity_endio(struct bio *bio)
{
	return true;
}
#endif

void blk_timeout_work(struct work_struct *work);
unsigned long blk_rq_timeout(unsigned long timeout);
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 bio_attempt_discard_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,
			    struct request **same_queue_rq);
unsigned int blk_plug_queued_count(struct request_queue *q);

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, u64 now);

/*
 * EH timer and IO completion will both attempt to 'grab' the request, make
 * sure that only one of them succeeds. Steal the bottom bit of the
 * __deadline field for this.
 */
static inline int blk_mark_rq_complete(struct request *rq)
{
	return test_and_set_bit(0, &rq->__deadline);
}

static inline void blk_clear_rq_complete(struct request *rq)
{
	clear_bit(0, &rq->__deadline);
}

static inline bool blk_rq_is_complete(struct request *rq)
{
	return test_bit(0, &rq->__deadline);
}

/*
 * Internal elevator interface
 */
#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)

void blk_insert_flush(struct request *rq);

static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
{
	struct elevator_queue *e = q->elevator;

	if (e->type->ops.sq.elevator_activate_req_fn)
		e->type->ops.sq.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.sq.elevator_deactivate_req_fn)
		e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
}

int elevator_init(struct request_queue *);
int elevator_init_mq(struct request_queue *q);
void elevator_exit(struct request_queue *, struct elevator_queue *);
int elv_register_queue(struct request_queue *q);
void elv_unregister_queue(struct request_queue *q);

struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);

#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);
struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
struct request *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);
enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);

void blk_queue_congestion_threshold(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;
}

extern int blk_update_nr_requests(struct request_queue *, unsigned int);

/*
 * 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->rq_flags & RQF_IO_STAT) &&
		!blk_rq_is_passthrough(rq);
}

static inline void req_set_nomerge(struct request_queue *q, struct request *req)
{
	req->cmd_flags |= REQ_NOMERGE;
	if (req == q->last_merge)
		q->last_merge = NULL;
}

/*
 * Steal a bit from this field for legacy IO path atomic IO marking. Note that
 * setting the deadline clears the bottom bit, potentially clearing the
 * completed bit. The user has to be OK with this (current ones are fine).
 */
static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
{
	rq->__deadline = time & ~0x1UL;
}

static inline unsigned long blk_rq_deadline(struct request *rq)
{
	return rq->__deadline & ~0x1UL;
}

/*
 * 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);

/**
 * rq_ioc - determine io_context for request allocation
 * @bio: request being allocated is for this bio (can be %NULL)
 *
 * Determine io_context to use for request allocation for @bio.  May return
 * %NULL if %current->io_context doesn't exist.
 */
static inline struct io_context *rq_ioc(struct bio *bio)
{
#ifdef CONFIG_BLK_CGROUP
	if (bio && bio->bi_ioc)
		return bio->bi_ioc;
#endif
	return current->io_context;
}

/**
 * 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 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_register_queue(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
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_register_queue(struct request_queue *q) { }
#endif /* CONFIG_BLK_DEV_THROTTLING */
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
	const char *page, size_t count);
extern void blk_throtl_bio_endio(struct bio *bio);
extern void blk_throtl_stat_add(struct request *rq, u64 time);
#else
static inline void blk_throtl_bio_endio(struct bio *bio) { }
static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
#endif

#ifdef CONFIG_BOUNCE
extern int init_emergency_isa_pool(void);
extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
#else
static inline int init_emergency_isa_pool(void)
{
	return 0;
}
static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
{
}
#endif /* CONFIG_BOUNCE */

extern void blk_drain_queue(struct request_queue *q);

#endif /* BLK_INTERNAL_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
8324aa91 JA	2	#ifndef BLK_INTERNAL_H
	3	#define BLK_INTERNAL_H
	4
a73f730d	5	#include <linux/idr.h>
f70ced09 ML	6	#include <linux/blk-mq.h>
f70ced09 ML	7	#include "blk-mq.h"
a73f730d	8
86db1e29 JA	9	/* Amount of time in which a process may batch requests */
	10	#define BLK_BATCH_TIME (HZ/50UL)
	11
	12	/* Number of requests a "batching" process may submit */
	13	#define BLK_BATCH_REQ 32
	14
0d2602ca JA	15	/* Max future timer expiry for timeouts */
	16	#define BLK_MAX_TIMEOUT (5 * HZ)
	17
18fbda91 OS	18	#ifdef CONFIG_DEBUG_FS
	19	extern struct dentry *blk_debugfs_root;
	20	#endif
	21
7c94e1c1 ML	22	struct blk_flush_queue {
	23	unsigned int flush_queue_delayed:1;
	24	unsigned int flush_pending_idx:1;
	25	unsigned int flush_running_idx:1;
	26	unsigned long flush_pending_since;
	27	struct list_head flush_queue[2];
	28	struct list_head flush_data_in_flight;
	29	struct request *flush_rq;
0048b483 ML	30
	31	/*
	32	* flush_rq shares tag with this rq, both can't be active
	33	* at the same time
	34	*/
	35	struct request *orig_rq;
7c94e1c1 ML	36	spinlock_t mq_flush_lock;
	37	};
	38
8324aa91	39	extern struct kmem_cache *blk_requestq_cachep;
320ae51f	40	extern struct kmem_cache *request_cachep;
8324aa91	41	extern struct kobj_type blk_queue_ktype;
a73f730d	42	extern struct ida blk_queue_ida;
8324aa91	43
8a0ac14b BVA	44	/*
	45	* @q->queue_lock is set while a queue is being initialized. Since we know
	46	* that no other threads access the queue object before @q->queue_lock has
	47	* been set, it is safe to manipulate queue flags without holding the
	48	* queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and
	49	* blk_init_allocated_queue().
	50	*/
	51	static inline void queue_lockdep_assert_held(struct request_queue *q)
	52	{
	53	if (q->queue_lock)
	54	lockdep_assert_held(q->queue_lock);
	55	}
	56
	57	static inline void queue_flag_set_unlocked(unsigned int flag,
	58	struct request_queue *q)
	59	{
	60	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
	61	kref_read(&q->kobj.kref))
	62	lockdep_assert_held(q->queue_lock);
	63	__set_bit(flag, &q->queue_flags);
	64	}
	65
	66	static inline void queue_flag_clear_unlocked(unsigned int flag,
	67	struct request_queue *q)
	68	{
	69	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
	70	kref_read(&q->kobj.kref))
	71	lockdep_assert_held(q->queue_lock);
	72	__clear_bit(flag, &q->queue_flags);
	73	}
	74
	75	static inline int queue_flag_test_and_clear(unsigned int flag,
	76	struct request_queue *q)
	77	{
	78	queue_lockdep_assert_held(q);
	79
	80	if (test_bit(flag, &q->queue_flags)) {
	81	__clear_bit(flag, &q->queue_flags);
	82	return 1;
	83	}
	84
	85	return 0;
	86	}
	87
	88	static inline int queue_flag_test_and_set(unsigned int flag,
	89	struct request_queue *q)
	90	{
	91	queue_lockdep_assert_held(q);
	92
	93	if (!test_bit(flag, &q->queue_flags)) {
	94	__set_bit(flag, &q->queue_flags);
	95	return 0;
	96	}
	97
	98	return 1;
	99	}
	100
	101	static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
	102	{
	103	queue_lockdep_assert_held(q);
	104	__set_bit(flag, &q->queue_flags);
	105	}
	106
	107	static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
108	{
109	queue_lockdep_assert_held(q);
110	__clear_bit(flag, &q->queue_flags);
111	}
112
7c94e1c1	113	static inline struct blk_flush_queue *blk_get_flush_queue(
e97c293c	114	struct request_queue q, struct blk_mq_ctx ctx)
7c94e1c1	115	{
7d7e0f90 CH	116	if (q->mq_ops)
	117	return blk_mq_map_queue(q, ctx->cpu)->fq;
	118	return q->fq;
7c94e1c1 ML	119	}
7c94e1c1 ML	120
09ac46c4 TH	121	static inline void __blk_get_queue(struct request_queue *q)
	122	{
	123	kobject_get(&q->kobj);
	124	}
	125
f70ced09 ML	126	struct blk_flush_queue blk_alloc_flush_queue(struct request_queue q,
	127	int node, int cmd_size);
	128	void blk_free_flush_queue(struct blk_flush_queue *q);
f3552655	129
5b788ce3 TH	130	int blk_init_rl(struct request_list rl, struct request_queue q,
5b788ce3 TH	131	gfp_t gfp_mask);
b425e504	132	void blk_exit_rl(struct request_queue q, struct request_list rl);
86db1e29 JA	133	void blk_rq_bio_prep(struct request_queue q, struct request rq,
86db1e29 JA	134	struct bio *bio);
d732580b TH	135	void blk_queue_bypass_start(struct request_queue *q);
d732580b TH	136	void blk_queue_bypass_end(struct request_queue *q);
8324aa91	137	void __blk_queue_free_tags(struct request_queue *q);
3ef28e83 DW	138	void blk_freeze_queue(struct request_queue *q);
	139
	140	static inline void blk_queue_enter_live(struct request_queue *q)
	141	{
	142	/*
	143	* Given that running in generic_make_request() context
	144	* guarantees that a live reference against q_usage_counter has
	145	* been established, further references under that same context
	146	* need not check that the queue has been frozen (marked dead).
	147	*/
	148	percpu_ref_get(&q->q_usage_counter);
	149	}
8324aa91	150
5a48fc14 DW	151	#ifdef CONFIG_BLK_DEV_INTEGRITY
5a48fc14 DW	152	void blk_flush_integrity(void);
7c20f116 CH	153	bool __bio_integrity_endio(struct bio *);
	154	static inline bool bio_integrity_endio(struct bio *bio)
	155	{
	156	if (bio_integrity(bio))
	157	return __bio_integrity_endio(bio);
	158	return true;
	159	}
5a48fc14 DW	160	#else
	161	static inline void blk_flush_integrity(void)
	162	{
	163	}
7c20f116 CH	164	static inline bool bio_integrity_endio(struct bio *bio)
	165	{
	166	return true;
	167	}
5a48fc14	168	#endif
8324aa91	169
287922eb	170	void blk_timeout_work(struct work_struct *work);
0d2602ca	171	unsigned long blk_rq_timeout(unsigned long timeout);
87ee7b11	172	void blk_add_timer(struct request *req);
242f9dcb	173	void blk_delete_timer(struct request *);
242f9dcb	174
320ae51f JA	175
	176	bool bio_attempt_front_merge(struct request_queue q, struct request req,
	177	struct bio *bio);
	178	bool bio_attempt_back_merge(struct request_queue q, struct request req,
	179	struct bio *bio);
1e739730 CH	180	bool bio_attempt_discard_merge(struct request_queue q, struct request req,
1e739730 CH	181	struct bio *bio);
320ae51f	182	bool blk_attempt_plug_merge(struct request_queue q, struct bio bio,
5b3f341f SL	183	unsigned int *request_count,
5b3f341f SL	184	struct request **same_queue_rq);
0809e3ac	185	unsigned int blk_plug_queued_count(struct request_queue *q);
320ae51f JA	186
	187	void blk_account_io_start(struct request *req, bool new_io);
	188	void blk_account_io_completion(struct request *req, unsigned int bytes);
522a7775	189	void blk_account_io_done(struct request *req, u64 now);
320ae51f	190
242f9dcb JA	191	/*
242f9dcb JA	192	* EH timer and IO completion will both attempt to 'grab' the request, make
e14575b3 JA	193	* sure that only one of them succeeds. Steal the bottom bit of the
e14575b3 JA	194	* __deadline field for this.
242f9dcb JA	195	*/
	196	static inline int blk_mark_rq_complete(struct request *rq)
	197	{
e14575b3	198	return test_and_set_bit(0, &rq->__deadline);
242f9dcb JA	199	}
	200
	201	static inline void blk_clear_rq_complete(struct request *rq)
	202	{
e14575b3 JA	203	clear_bit(0, &rq->__deadline);
	204	}
	205
	206	static inline bool blk_rq_is_complete(struct request *rq)
	207	{
	208	return test_bit(0, &rq->__deadline);
242f9dcb	209	}
86db1e29	210
158dbda0 TH	211	/*
	212	* Internal elevator interface
	213	*/
e8064021	214	#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
158dbda0	215
ae1b1539	216	void blk_insert_flush(struct request *rq);
dd831006	217
158dbda0 TH	218	static inline void elv_activate_rq(struct request_queue q, struct request rq)
	219	{
	220	struct elevator_queue *e = q->elevator;
	221
c51ca6cf JA	222	if (e->type->ops.sq.elevator_activate_req_fn)
c51ca6cf JA	223	e->type->ops.sq.elevator_activate_req_fn(q, rq);
158dbda0 TH	224	}
	225
	226	static inline void elv_deactivate_rq(struct request_queue q, struct request rq)
	227	{
	228	struct elevator_queue *e = q->elevator;
	229
c51ca6cf JA	230	if (e->type->ops.sq.elevator_deactivate_req_fn)
c51ca6cf JA	231	e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
158dbda0 TH	232	}
158dbda0 TH	233
ddb72532	234	int elevator_init(struct request_queue *);
131d08e1	235	int elevator_init_mq(struct request_queue *q);
a8a275c9	236	void elevator_exit(struct request_queue , struct elevator_queue );
83d016ac BVA	237	int elv_register_queue(struct request_queue *q);
	238	void elv_unregister_queue(struct request_queue *q);
	239
807d4af2 CH	240	struct hd_struct __disk_get_part(struct gendisk disk, int partno);
807d4af2 CH	241
581d4e28 JA	242	#ifdef CONFIG_FAIL_IO_TIMEOUT
	243	int blk_should_fake_timeout(struct request_queue *);
	244	ssize_t part_timeout_show(struct device , struct device_attribute , char *);
	245	ssize_t part_timeout_store(struct device , struct device_attribute ,
	246	const char *, size_t);
	247	#else
	248	static inline int blk_should_fake_timeout(struct request_queue *q)
	249	{
	250	return 0;
	251	}
	252	#endif
	253
d6d48196 JA	254	int ll_back_merge_fn(struct request_queue q, struct request req,
	255	struct bio *bio);
	256	int ll_front_merge_fn(struct request_queue q, struct request req,
	257	struct bio *bio);
b973cb7e JA	258	struct request attempt_back_merge(struct request_queue q, struct request *rq);
b973cb7e JA	259	struct request attempt_front_merge(struct request_queue q, struct request *rq);
5e84ea3a JA	260	int blk_attempt_req_merge(struct request_queue q, struct request rq,
5e84ea3a JA	261	struct request *next);
d6d48196	262	void blk_recalc_rq_segments(struct request *rq);
80a761fd	263	void blk_rq_set_mixed_merge(struct request *rq);
050c8ea8	264	bool blk_rq_merge_ok(struct request rq, struct bio bio);
34fe7c05	265	enum elv_merge blk_try_merge(struct request rq, struct bio bio);
d6d48196	266
8324aa91 JA	267	void blk_queue_congestion_threshold(struct request_queue *q);
8324aa91 JA	268
ff88972c AB	269	int blk_dev_init(void);
ff88972c AB	270
f253b86b	271
8324aa91 JA	272	/*
	273	* Return the threshold (number of used requests) at which the queue is
	274	* considered to be congested. It include a little hysteresis to keep the
	275	* context switch rate down.
	276	*/
	277	static inline int queue_congestion_on_threshold(struct request_queue *q)
	278	{
	279	return q->nr_congestion_on;
	280	}
	281
	282	/*
	283	* The threshold at which a queue is considered to be uncongested
	284	*/
	285	static inline int queue_congestion_off_threshold(struct request_queue *q)
	286	{
	287	return q->nr_congestion_off;
	288	}
	289
e3a2b3f9 JA	290	extern int blk_update_nr_requests(struct request_queue *, unsigned int);
e3a2b3f9 JA	291
c2553b58 JA	292	/*
	293	* Contribute to IO statistics IFF:
	294	*
	295	* a) it's attached to a gendisk, and
	296	* b) the queue had IO stats enabled when this request was started, and
e2a60da7	297	* c) it's a file system request
c2553b58	298	*/
26308eab	299	static inline int blk_do_io_stat(struct request *rq)
fb8ec18c	300	{
33659ebb	301	return rq->rq_disk &&
e8064021	302	(rq->rq_flags & RQF_IO_STAT) &&
57292b58	303	!blk_rq_is_passthrough(rq);
fb8ec18c JA	304	}
fb8ec18c JA	305
6cf7677f CH	306	static inline void req_set_nomerge(struct request_queue q, struct request req)
	307	{
	308	req->cmd_flags \|= REQ_NOMERGE;
	309	if (req == q->last_merge)
	310	q->last_merge = NULL;
	311	}
	312
0a72e7f4 JA	313	/*
	314	* Steal a bit from this field for legacy IO path atomic IO marking. Note that
	315	* setting the deadline clears the bottom bit, potentially clearing the
	316	* completed bit. The user has to be OK with this (current ones are fine).
	317	*/
	318	static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
	319	{
	320	rq->__deadline = time & ~0x1UL;
	321	}
	322
	323	static inline unsigned long blk_rq_deadline(struct request *rq)
	324	{
	325	return rq->__deadline & ~0x1UL;
	326	}
	327
f2dbd76a TH	328	/*
	329	* Internal io_context interface
	330	*/
	331	void get_io_context(struct io_context *ioc);
47fdd4ca	332	struct io_cq ioc_lookup_icq(struct io_context ioc, struct request_queue *q);
24acfc34 TH	333	struct io_cq ioc_create_icq(struct io_context ioc, struct request_queue *q,
24acfc34 TH	334	gfp_t gfp_mask);
7e5a8794	335	void ioc_clear_queue(struct request_queue *q);
f2dbd76a	336
24acfc34	337	int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
f2dbd76a	338
c23ecb42 JA	339	/**
	340	* rq_ioc - determine io_context for request allocation
	341	* @bio: request being allocated is for this bio (can be %NULL)
	342	*
	343	* Determine io_context to use for request allocation for @bio. May return
	344	* %NULL if %current->io_context doesn't exist.
	345	*/
	346	static inline struct io_context rq_ioc(struct bio bio)
	347	{
	348	#ifdef CONFIG_BLK_CGROUP
	349	if (bio && bio->bi_ioc)
	350	return bio->bi_ioc;
	351	#endif
	352	return current->io_context;
	353	}
	354
f2dbd76a TH	355	/**
f2dbd76a TH	356	* create_io_context - try to create task->io_context
f2dbd76a TH	357	* @gfp_mask: allocation mask
	358	* @node: allocation node
	359	*
24acfc34 TH	360	* If %current->io_context is %NULL, allocate a new io_context and install
	361	* it. Returns the current %current->io_context which may be %NULL if
	362	* allocation failed.
f2dbd76a TH	363	*
f2dbd76a TH	364	* Note that this function can't be called with IRQ disabled because
24acfc34	365	* task_lock which protects %current->io_context is IRQ-unsafe.
f2dbd76a	366	*/
24acfc34	367	static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
f2dbd76a TH	368	{
f2dbd76a TH	369	WARN_ON_ONCE(irqs_disabled());
24acfc34 TH	370	if (unlikely(!current->io_context))
	371	create_task_io_context(current, gfp_mask, node);
	372	return current->io_context;
f2dbd76a TH	373	}
	374
	375	/*
	376	* Internal throttling interface
	377	*/
bc9fcbf9	378	#ifdef CONFIG_BLK_DEV_THROTTLING
c9a929dd	379	extern void blk_throtl_drain(struct request_queue *q);
bc9fcbf9 TH	380	extern int blk_throtl_init(struct request_queue *q);
bc9fcbf9 TH	381	extern void blk_throtl_exit(struct request_queue *q);
d61fcfa4	382	extern void blk_throtl_register_queue(struct request_queue *q);
bc9fcbf9	383	#else /* CONFIG_BLK_DEV_THROTTLING */
c9a929dd	384	static inline void blk_throtl_drain(struct request_queue *q) { }
bc9fcbf9 TH	385	static inline int blk_throtl_init(struct request_queue *q) { return 0; }
bc9fcbf9 TH	386	static inline void blk_throtl_exit(struct request_queue *q) { }
d61fcfa4	387	static inline void blk_throtl_register_queue(struct request_queue *q) { }
bc9fcbf9	388	#endif /* CONFIG_BLK_DEV_THROTTLING */
297e3d85 SL	389	#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
	390	extern ssize_t blk_throtl_sample_time_show(struct request_queue q, char page);
	391	extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
	392	const char *page, size_t count);
9e234eea	393	extern void blk_throtl_bio_endio(struct bio *bio);
b9147dd1	394	extern void blk_throtl_stat_add(struct request *rq, u64 time);
9e234eea SL	395	#else
9e234eea SL	396	static inline void blk_throtl_bio_endio(struct bio *bio) { }
b9147dd1	397	static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
297e3d85	398	#endif
bc9fcbf9	399
3bce016a CH	400	#ifdef CONFIG_BOUNCE
	401	extern int init_emergency_isa_pool(void);
	402	extern void blk_queue_bounce(struct request_queue q, struct bio *bio);
	403	#else
	404	static inline int init_emergency_isa_pool(void)
	405	{
	406	return 0;
	407	}
	408	static inline void blk_queue_bounce(struct request_queue q, struct bio *bio)
	409	{
	410	}
	411	#endif /* CONFIG_BOUNCE */
	412
454be724 ML	413	extern void blk_drain_queue(struct request_queue *q);
454be724 ML	414
bc9fcbf9	415	#endif /* BLK_INTERNAL_H */