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

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

#include <linux/blkdev.h>
#include <linux/sbitmap.h>
#include <linux/srcu.h>

struct blk_mq_tags;
struct blk_flush_queue;

/**
 * struct blk_mq_hw_ctx - State for a hardware queue facing the hardware block device
 */
struct blk_mq_hw_ctx {
	struct {
		spinlock_t		lock;
		struct list_head	dispatch;
		unsigned long		state;		/* BLK_MQ_S_* flags */
	} ____cacheline_aligned_in_smp;

	struct delayed_work	run_work;
	cpumask_var_t		cpumask;
	int			next_cpu;
	int			next_cpu_batch;

	unsigned long		flags;		/* BLK_MQ_F_* flags */

	void			*sched_data;
	struct request_queue	*queue;
	struct blk_flush_queue	*fq;

	void			*driver_data;

	struct sbitmap		ctx_map;

	struct blk_mq_ctx	*dispatch_from;
	unsigned int		dispatch_busy;

	unsigned short		type;
	unsigned short		nr_ctx;
	struct blk_mq_ctx	**ctxs;

	spinlock_t		dispatch_wait_lock;
	wait_queue_entry_t	dispatch_wait;
	atomic_t		wait_index;

	struct blk_mq_tags	*tags;
	struct blk_mq_tags	*sched_tags;

	unsigned long		queued;
	unsigned long		run;
#define BLK_MQ_MAX_DISPATCH_ORDER	7
	unsigned long		dispatched[BLK_MQ_MAX_DISPATCH_ORDER];

	unsigned int		numa_node;
	unsigned int		queue_num;

	atomic_t		nr_active;

	struct hlist_node	cpuhp_dead;
	struct kobject		kobj;

	unsigned long		poll_considered;
	unsigned long		poll_invoked;
	unsigned long		poll_success;

#ifdef CONFIG_BLK_DEBUG_FS
	struct dentry		*debugfs_dir;
	struct dentry		*sched_debugfs_dir;
#endif

	struct list_head	hctx_list;

	/* Must be the last member - see also blk_mq_hw_ctx_size(). */
	struct srcu_struct	srcu[0];
};

/**
 * struct blk_mq_queue_map - ctx -> hctx mapping
 * @mq_map:       CPU ID to hardware queue index map. This is an array
 *	with nr_cpu_ids elements. Each element has a value in the range
 *	[@queue_offset, @queue_offset + @nr_queues).
 * @nr_queues:    Number of hardware queues to map CPU IDs onto.
 * @queue_offset: First hardware queue to map onto. Used by the PCIe NVMe
 *	driver to map each hardware queue type (enum hctx_type) onto a distinct
 *	set of hardware queues.
 */
struct blk_mq_queue_map {
	unsigned int *mq_map;
	unsigned int nr_queues;
	unsigned int queue_offset;
};

enum hctx_type {
	HCTX_TYPE_DEFAULT,	/* all I/O not otherwise accounted for */
	HCTX_TYPE_READ,		/* just for READ I/O */
	HCTX_TYPE_POLL,		/* polled I/O of any kind */

	HCTX_MAX_TYPES,
};

/**
 * struct blk_mq_tag_set - tag set that can be shared between request queues
 * @map:	   One or more ctx -> hctx mappings. One map exists for each
 *		   hardware queue type (enum hctx_type) that the driver wishes
 *		   to support. There are no restrictions on maps being of the
 *		   same size, and it's perfectly legal to share maps between
 *		   types.
 * @nr_maps:	   Number of elements in the @map array. A number in the range
 *		   [1, HCTX_MAX_TYPES].
 * @ops:	   Pointers to functions that implement block driver behavior.
 * @nr_hw_queues:  Number of hardware queues supported by the block driver that
 *		   owns this data structure.
 * @queue_depth:   Number of tags per hardware queue, reserved tags included.
 * @reserved_tags: Number of tags to set aside for BLK_MQ_REQ_RESERVED tag
 *		   allocations.
 * @cmd_size:	   Number of additional bytes to allocate per request. The block
 *		   driver owns these additional bytes.
 * @numa_node:	   NUMA node the storage adapter has been connected to.
 * @timeout:	   Request processing timeout in jiffies.
 * @flags:	   Zero or more BLK_MQ_F_* flags.
 * @driver_data:   Pointer to data owned by the block driver that created this
 *		   tag set.
 * @tags:	   Tag sets. One tag set per hardware queue. Has @nr_hw_queues
 *		   elements.
 * @tag_list_lock: Serializes tag_list accesses.
 * @tag_list:	   List of the request queues that use this tag set. See also
 *		   request_queue.tag_set_list.
 */
struct blk_mq_tag_set {
	struct blk_mq_queue_map	map[HCTX_MAX_TYPES];
	unsigned int		nr_maps;
	const struct blk_mq_ops	*ops;
	unsigned int		nr_hw_queues;
	unsigned int		queue_depth;
	unsigned int		reserved_tags;
	unsigned int		cmd_size;
	int			numa_node;
	unsigned int		timeout;
	unsigned int		flags;
	void			*driver_data;

	struct blk_mq_tags	**tags;

	struct mutex		tag_list_lock;
	struct list_head	tag_list;
};

struct blk_mq_queue_data {
	struct request *rq;
	bool last;
};

typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
		const struct blk_mq_queue_data *);
typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
typedef int (init_request_fn)(struct blk_mq_tag_set *set, struct request *,
		unsigned int, unsigned int);
typedef void (exit_request_fn)(struct blk_mq_tag_set *set, struct request *,
		unsigned int);

typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
		bool);
typedef bool (busy_tag_iter_fn)(struct request *, void *, bool);
typedef int (poll_fn)(struct blk_mq_hw_ctx *);
typedef int (map_queues_fn)(struct blk_mq_tag_set *set);
typedef bool (busy_fn)(struct request_queue *);
typedef void (complete_fn)(struct request *);
typedef void (cleanup_rq_fn)(struct request *);


struct blk_mq_ops {
	/*
	 * Queue request
	 */
	queue_rq_fn		*queue_rq;

	/*
	 * If a driver uses bd->last to judge when to submit requests to
	 * hardware, it must define this function. In case of errors that
	 * make us stop issuing further requests, this hook serves the
	 * purpose of kicking the hardware (which the last request otherwise
	 * would have done).
	 */
	commit_rqs_fn		*commit_rqs;

	/*
	 * Reserve budget before queue request, once .queue_rq is
	 * run, it is driver's responsibility to release the
	 * reserved budget. Also we have to handle failure case
	 * of .get_budget for avoiding I/O deadlock.
	 */
	get_budget_fn		*get_budget;
	put_budget_fn		*put_budget;

	/*
	 * Called on request timeout
	 */
	timeout_fn		*timeout;

	/*
	 * Called to poll for completion of a specific tag.
	 */
	poll_fn			*poll;

	complete_fn		*complete;

	/*
	 * Called when the block layer side of a hardware queue has been
	 * set up, allowing the driver to allocate/init matching structures.
	 * Ditto for exit/teardown.
	 */
	init_hctx_fn		*init_hctx;
	exit_hctx_fn		*exit_hctx;

	/*
	 * Called for every command allocated by the block layer to allow
	 * the driver to set up driver specific data.
	 *
	 * Tag greater than or equal to queue_depth is for setting up
	 * flush request.
	 *
	 * Ditto for exit/teardown.
	 */
	init_request_fn		*init_request;
	exit_request_fn		*exit_request;
	/* Called from inside blk_get_request() */
	void (*initialize_rq_fn)(struct request *rq);

	/*
	 * Called before freeing one request which isn't completed yet,
	 * and usually for freeing the driver private data
	 */
	cleanup_rq_fn		*cleanup_rq;

	/*
	 * If set, returns whether or not this queue currently is busy
	 */
	busy_fn			*busy;

	map_queues_fn		*map_queues;

#ifdef CONFIG_BLK_DEBUG_FS
	/*
	 * Used by the debugfs implementation to show driver-specific
	 * information about a request.
	 */
	void (*show_rq)(struct seq_file *m, struct request *rq);
#endif
};

enum {
	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
	BLK_MQ_F_TAG_SHARED	= 1 << 1,
	BLK_MQ_F_BLOCKING	= 1 << 5,
	BLK_MQ_F_NO_SCHED	= 1 << 6,
	BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
	BLK_MQ_F_ALLOC_POLICY_BITS = 1,

	BLK_MQ_S_STOPPED	= 0,
	BLK_MQ_S_TAG_ACTIVE	= 1,
	BLK_MQ_S_SCHED_RESTART	= 2,

	BLK_MQ_MAX_DEPTH	= 10240,

	BLK_MQ_CPU_WORK_BATCH	= 8,
};
#define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
	((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
		((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
#define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
	((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
		<< BLK_MQ_F_ALLOC_POLICY_START_BIT)

struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
						  struct request_queue *q,
						  bool elevator_init);
struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
						const struct blk_mq_ops *ops,
						unsigned int queue_depth,
						unsigned int set_flags);
void blk_mq_unregister_dev(struct device *, struct request_queue *);

int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set);
void blk_mq_free_tag_set(struct blk_mq_tag_set *set);

void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);

void blk_mq_free_request(struct request *rq);
bool blk_mq_can_queue(struct blk_mq_hw_ctx *);

bool blk_mq_queue_inflight(struct request_queue *q);

enum {
	/* return when out of requests */
	BLK_MQ_REQ_NOWAIT	= (__force blk_mq_req_flags_t)(1 << 0),
	/* allocate from reserved pool */
	BLK_MQ_REQ_RESERVED	= (__force blk_mq_req_flags_t)(1 << 1),
	/* allocate internal/sched tag */
	BLK_MQ_REQ_INTERNAL	= (__force blk_mq_req_flags_t)(1 << 2),
	/* set RQF_PREEMPT */
	BLK_MQ_REQ_PREEMPT	= (__force blk_mq_req_flags_t)(1 << 3),
};

struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
		blk_mq_req_flags_t flags);
struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
		unsigned int op, blk_mq_req_flags_t flags,
		unsigned int hctx_idx);
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);

enum {
	BLK_MQ_UNIQUE_TAG_BITS = 16,
	BLK_MQ_UNIQUE_TAG_MASK = (1 << BLK_MQ_UNIQUE_TAG_BITS) - 1,
};

u32 blk_mq_unique_tag(struct request *rq);

static inline u16 blk_mq_unique_tag_to_hwq(u32 unique_tag)
{
	return unique_tag >> BLK_MQ_UNIQUE_TAG_BITS;
}

static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
{
	return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
}


int blk_mq_request_started(struct request *rq);
int blk_mq_request_completed(struct request *rq);
void blk_mq_start_request(struct request *rq);
void blk_mq_end_request(struct request *rq, blk_status_t error);
void __blk_mq_end_request(struct request *rq, blk_status_t error);

void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
void blk_mq_kick_requeue_list(struct request_queue *q);
void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
bool blk_mq_complete_request(struct request *rq);
bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
			   struct bio *bio, unsigned int nr_segs);
bool blk_mq_queue_stopped(struct request_queue *q);
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_stop_hw_queues(struct request_queue *q);
void blk_mq_start_hw_queues(struct request_queue *q);
void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
void blk_mq_quiesce_queue(struct request_queue *q);
void blk_mq_unquiesce_queue(struct request_queue *q);
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
void blk_mq_run_hw_queues(struct request_queue *q, bool async);
void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
		busy_tag_iter_fn *fn, void *priv);
void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset);
void blk_mq_freeze_queue(struct request_queue *q);
void blk_mq_unfreeze_queue(struct request_queue *q);
void blk_freeze_queue_start(struct request_queue *q);
void blk_mq_freeze_queue_wait(struct request_queue *q);
int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
				     unsigned long timeout);

int blk_mq_map_queues(struct blk_mq_queue_map *qmap);
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);

void blk_mq_quiesce_queue_nowait(struct request_queue *q);

unsigned int blk_mq_rq_cpu(struct request *rq);

/*
 * Driver command data is immediately after the request. So subtract request
 * size to get back to the original request, add request size to get the PDU.
 */
static inline struct request *blk_mq_rq_from_pdu(void *pdu)
{
	return pdu - sizeof(struct request);
}
static inline void *blk_mq_rq_to_pdu(struct request *rq)
{
	return rq + 1;
}

#define queue_for_each_hw_ctx(q, hctx, i)				\
	for ((i) = 0; (i) < (q)->nr_hw_queues &&			\
	     ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)

#define hctx_for_each_ctx(hctx, ctx, i)					\
	for ((i) = 0; (i) < (hctx)->nr_ctx &&				\
	     ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)

static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
		struct request *rq)
{
	if (rq->tag != -1)
		return rq->tag | (hctx->queue_num << BLK_QC_T_SHIFT);

	return rq->internal_tag | (hctx->queue_num << BLK_QC_T_SHIFT) |
			BLK_QC_T_INTERNAL;
}

static inline void blk_mq_cleanup_rq(struct request *rq)
{
	if (rq->q->mq_ops->cleanup_rq)
		rq->q->mq_ops->cleanup_rq(rq);
}

#endif
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef BLK_MQ_H
	3	#define BLK_MQ_H
	4
	5	#include <linux/blkdev.h>
	6	#include <linux/sbitmap.h>
	7	#include <linux/srcu.h>
	8
	9	struct blk_mq_tags;
	10	struct blk_flush_queue;
	11
	12	/**
	13	* struct blk_mq_hw_ctx - State for a hardware queue facing the hardware block device
	14	*/
	15	struct blk_mq_hw_ctx {
	16	struct {
	17	spinlock_t lock;
	18	struct list_head dispatch;
	19	unsigned long state; /* BLK_MQ_S_* flags */
	20	} ____cacheline_aligned_in_smp;
	21
	22	struct delayed_work run_work;
	23	cpumask_var_t cpumask;
	24	int next_cpu;
	25	int next_cpu_batch;
	26
	27	unsigned long flags; /* BLK_MQ_F_* flags */
	28
	29	void *sched_data;
	30	struct request_queue *queue;
	31	struct blk_flush_queue *fq;
	32
	33	void *driver_data;
	34
	35	struct sbitmap ctx_map;
	36
	37	struct blk_mq_ctx *dispatch_from;
	38	unsigned int dispatch_busy;
	39
	40	unsigned short type;
	41	unsigned short nr_ctx;
	42	struct blk_mq_ctx **ctxs;
	43
	44	spinlock_t dispatch_wait_lock;
	45	wait_queue_entry_t dispatch_wait;
	46	atomic_t wait_index;
	47
	48	struct blk_mq_tags *tags;
	49	struct blk_mq_tags *sched_tags;
	50
	51	unsigned long queued;
	52	unsigned long run;
	53	#define BLK_MQ_MAX_DISPATCH_ORDER 7
	54	unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER];
	55
	56	unsigned int numa_node;
	57	unsigned int queue_num;
	58
	59	atomic_t nr_active;
	60
	61	struct hlist_node cpuhp_dead;
	62	struct kobject kobj;
	63
	64	unsigned long poll_considered;
	65	unsigned long poll_invoked;
	66	unsigned long poll_success;
	67
	68	#ifdef CONFIG_BLK_DEBUG_FS
	69	struct dentry *debugfs_dir;
	70	struct dentry *sched_debugfs_dir;
	71	#endif
	72
	73	struct list_head hctx_list;
	74
	75	/* Must be the last member - see also blk_mq_hw_ctx_size(). */
	76	struct srcu_struct srcu[0];
	77	};
	78
	79	/**
	80	* struct blk_mq_queue_map - ctx -> hctx mapping
	81	* @mq_map: CPU ID to hardware queue index map. This is an array
	82	* with nr_cpu_ids elements. Each element has a value in the range
	83	* [@queue_offset, @queue_offset + @nr_queues).
	84	* @nr_queues: Number of hardware queues to map CPU IDs onto.
	85	* @queue_offset: First hardware queue to map onto. Used by the PCIe NVMe
	86	* driver to map each hardware queue type (enum hctx_type) onto a distinct
	87	* set of hardware queues.
	88	*/
	89	struct blk_mq_queue_map {
	90	unsigned int *mq_map;
	91	unsigned int nr_queues;
	92	unsigned int queue_offset;
	93	};
	94
	95	enum hctx_type {
	96	HCTX_TYPE_DEFAULT, /* all I/O not otherwise accounted for */
	97	HCTX_TYPE_READ, /* just for READ I/O */
	98	HCTX_TYPE_POLL, /* polled I/O of any kind */
	99
	100	HCTX_MAX_TYPES,
	101	};
	102
	103	/**
	104	* struct blk_mq_tag_set - tag set that can be shared between request queues
	105	* @map: One or more ctx -> hctx mappings. One map exists for each
	106	* hardware queue type (enum hctx_type) that the driver wishes
	107	* to support. There are no restrictions on maps being of the
	108	* same size, and it's perfectly legal to share maps between
	109	* types.
	110	* @nr_maps: Number of elements in the @map array. A number in the range
	111	* [1, HCTX_MAX_TYPES].
	112	* @ops: Pointers to functions that implement block driver behavior.
	113	* @nr_hw_queues: Number of hardware queues supported by the block driver that
	114	* owns this data structure.
	115	* @queue_depth: Number of tags per hardware queue, reserved tags included.
	116	* @reserved_tags: Number of tags to set aside for BLK_MQ_REQ_RESERVED tag
	117	* allocations.
	118	* @cmd_size: Number of additional bytes to allocate per request. The block
	119	* driver owns these additional bytes.
	120	* @numa_node: NUMA node the storage adapter has been connected to.
	121	* @timeout: Request processing timeout in jiffies.
	122	* @flags: Zero or more BLK_MQ_F_* flags.
	123	* @driver_data: Pointer to data owned by the block driver that created this
	124	* tag set.
	125	* @tags: Tag sets. One tag set per hardware queue. Has @nr_hw_queues
	126	* elements.
	127	* @tag_list_lock: Serializes tag_list accesses.
	128	* @tag_list: List of the request queues that use this tag set. See also
	129	* request_queue.tag_set_list.
	130	*/
	131	struct blk_mq_tag_set {
	132	struct blk_mq_queue_map map[HCTX_MAX_TYPES];
	133	unsigned int nr_maps;
	134	const struct blk_mq_ops *ops;
	135	unsigned int nr_hw_queues;
	136	unsigned int queue_depth;
	137	unsigned int reserved_tags;
	138	unsigned int cmd_size;
	139	int numa_node;
	140	unsigned int timeout;
	141	unsigned int flags;
	142	void *driver_data;
	143
	144	struct blk_mq_tags **tags;
	145
	146	struct mutex tag_list_lock;
	147	struct list_head tag_list;
	148	};
	149
	150	struct blk_mq_queue_data {
	151	struct request *rq;
	152	bool last;
	153	};
	154
	155	typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
	156	const struct blk_mq_queue_data *);
	157	typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
	158	typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
	159	typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
	160	typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
	161	typedef int (init_hctx_fn)(struct blk_mq_hw_ctx , void , unsigned int);
	162	typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
	163	typedef int (init_request_fn)(struct blk_mq_tag_set set, struct request ,
	164	unsigned int, unsigned int);
	165	typedef void (exit_request_fn)(struct blk_mq_tag_set set, struct request ,
	166	unsigned int);
	167
	168	typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx , struct request , void *,
	169	bool);
	170	typedef bool (busy_tag_iter_fn)(struct request , void , bool);
	171	typedef int (poll_fn)(struct blk_mq_hw_ctx *);
	172	typedef int (map_queues_fn)(struct blk_mq_tag_set *set);
	173	typedef bool (busy_fn)(struct request_queue *);
	174	typedef void (complete_fn)(struct request *);
	175	typedef void (cleanup_rq_fn)(struct request *);
	176
	177
	178	struct blk_mq_ops {
	179	/*
	180	* Queue request
	181	*/
	182	queue_rq_fn *queue_rq;
	183
	184	/*
	185	* If a driver uses bd->last to judge when to submit requests to
	186	* hardware, it must define this function. In case of errors that
	187	* make us stop issuing further requests, this hook serves the
	188	* purpose of kicking the hardware (which the last request otherwise
	189	* would have done).
	190	*/
	191	commit_rqs_fn *commit_rqs;
	192
	193	/*
	194	* Reserve budget before queue request, once .queue_rq is
	195	* run, it is driver's responsibility to release the
	196	* reserved budget. Also we have to handle failure case
	197	* of .get_budget for avoiding I/O deadlock.
	198	*/
	199	get_budget_fn *get_budget;
	200	put_budget_fn *put_budget;
	201
	202	/*
	203	* Called on request timeout
	204	*/
	205	timeout_fn *timeout;
	206
	207	/*
	208	* Called to poll for completion of a specific tag.
	209	*/
	210	poll_fn *poll;
	211
	212	complete_fn *complete;
	213
	214	/*
	215	* Called when the block layer side of a hardware queue has been
	216	* set up, allowing the driver to allocate/init matching structures.
	217	* Ditto for exit/teardown.
	218	*/
	219	init_hctx_fn *init_hctx;
	220	exit_hctx_fn *exit_hctx;
	221
	222	/*
	223	* Called for every command allocated by the block layer to allow
	224	* the driver to set up driver specific data.
	225	*
	226	* Tag greater than or equal to queue_depth is for setting up
	227	* flush request.
	228	*
	229	* Ditto for exit/teardown.
	230	*/
	231	init_request_fn *init_request;
	232	exit_request_fn *exit_request;
	233	/* Called from inside blk_get_request() */
	234	void (initialize_rq_fn)(struct request rq);
	235
	236	/*
	237	* Called before freeing one request which isn't completed yet,
	238	* and usually for freeing the driver private data
	239	*/
	240	cleanup_rq_fn *cleanup_rq;
	241
	242	/*
	243	* If set, returns whether or not this queue currently is busy
	244	*/
	245	busy_fn *busy;
	246
	247	map_queues_fn *map_queues;
	248
	249	#ifdef CONFIG_BLK_DEBUG_FS
	250	/*
	251	* Used by the debugfs implementation to show driver-specific
	252	* information about a request.
	253	*/
	254	void (show_rq)(struct seq_file m, struct request *rq);
	255	#endif
	256	};
	257
	258	enum {
	259	BLK_MQ_F_SHOULD_MERGE = 1 << 0,
	260	BLK_MQ_F_TAG_SHARED = 1 << 1,
	261	BLK_MQ_F_BLOCKING = 1 << 5,
	262	BLK_MQ_F_NO_SCHED = 1 << 6,
	263	BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
	264	BLK_MQ_F_ALLOC_POLICY_BITS = 1,
	265
	266	BLK_MQ_S_STOPPED = 0,
	267	BLK_MQ_S_TAG_ACTIVE = 1,
	268	BLK_MQ_S_SCHED_RESTART = 2,
	269
	270	BLK_MQ_MAX_DEPTH = 10240,
	271
	272	BLK_MQ_CPU_WORK_BATCH = 8,
	273	};
	274	#define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
	275	((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
	276	((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
	277	#define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
	278	((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
	279	<< BLK_MQ_F_ALLOC_POLICY_START_BIT)
	280
	281	struct request_queue blk_mq_init_queue(struct blk_mq_tag_set );
	282	struct request_queue blk_mq_init_allocated_queue(struct blk_mq_tag_set set,
	283	struct request_queue *q,
	284	bool elevator_init);
	285	struct request_queue blk_mq_init_sq_queue(struct blk_mq_tag_set set,
	286	const struct blk_mq_ops *ops,
	287	unsigned int queue_depth,
	288	unsigned int set_flags);
	289	void blk_mq_unregister_dev(struct device , struct request_queue );
	290
	291	int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set);
	292	void blk_mq_free_tag_set(struct blk_mq_tag_set *set);
	293
	294	void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
	295
	296	void blk_mq_free_request(struct request *rq);
	297	bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
	298
	299	bool blk_mq_queue_inflight(struct request_queue *q);
	300
	301	enum {
	302	/* return when out of requests */
	303	BLK_MQ_REQ_NOWAIT = (__force blk_mq_req_flags_t)(1 << 0),
	304	/* allocate from reserved pool */
	305	BLK_MQ_REQ_RESERVED = (__force blk_mq_req_flags_t)(1 << 1),
	306	/* allocate internal/sched tag */
	307	BLK_MQ_REQ_INTERNAL = (__force blk_mq_req_flags_t)(1 << 2),
	308	/* set RQF_PREEMPT */
	309	BLK_MQ_REQ_PREEMPT = (__force blk_mq_req_flags_t)(1 << 3),
	310	};
	311
	312	struct request blk_mq_alloc_request(struct request_queue q, unsigned int op,
	313	blk_mq_req_flags_t flags);
	314	struct request blk_mq_alloc_request_hctx(struct request_queue q,
	315	unsigned int op, blk_mq_req_flags_t flags,
	316	unsigned int hctx_idx);
	317	struct request blk_mq_tag_to_rq(struct blk_mq_tags tags, unsigned int tag);
	318
	319	enum {
	320	BLK_MQ_UNIQUE_TAG_BITS = 16,
	321	BLK_MQ_UNIQUE_TAG_MASK = (1 << BLK_MQ_UNIQUE_TAG_BITS) - 1,
	322	};
	323
	324	u32 blk_mq_unique_tag(struct request *rq);
	325
	326	static inline u16 blk_mq_unique_tag_to_hwq(u32 unique_tag)
	327	{
	328	return unique_tag >> BLK_MQ_UNIQUE_TAG_BITS;
	329	}
	330
	331	static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
	332	{
	333	return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
	334	}
	335
	336
	337	int blk_mq_request_started(struct request *rq);
	338	int blk_mq_request_completed(struct request *rq);
	339	void blk_mq_start_request(struct request *rq);
	340	void blk_mq_end_request(struct request *rq, blk_status_t error);
	341	void __blk_mq_end_request(struct request *rq, blk_status_t error);
	342
	343	void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
	344	void blk_mq_kick_requeue_list(struct request_queue *q);
	345	void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
	346	bool blk_mq_complete_request(struct request *rq);
	347	bool blk_mq_bio_list_merge(struct request_queue q, struct list_head list,
	348	struct bio *bio, unsigned int nr_segs);
	349	bool blk_mq_queue_stopped(struct request_queue *q);
	350	void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
	351	void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
	352	void blk_mq_stop_hw_queues(struct request_queue *q);
	353	void blk_mq_start_hw_queues(struct request_queue *q);
	354	void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
	355	void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
	356	void blk_mq_quiesce_queue(struct request_queue *q);
	357	void blk_mq_unquiesce_queue(struct request_queue *q);
	358	void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
	359	bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
	360	void blk_mq_run_hw_queues(struct request_queue *q, bool async);
	361	void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
	362	busy_tag_iter_fn fn, void priv);
	363	void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset);
	364	void blk_mq_freeze_queue(struct request_queue *q);
	365	void blk_mq_unfreeze_queue(struct request_queue *q);
	366	void blk_freeze_queue_start(struct request_queue *q);
	367	void blk_mq_freeze_queue_wait(struct request_queue *q);
	368	int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
	369	unsigned long timeout);
	370
	371	int blk_mq_map_queues(struct blk_mq_queue_map *qmap);
	372	void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
	373
	374	void blk_mq_quiesce_queue_nowait(struct request_queue *q);
	375
	376	unsigned int blk_mq_rq_cpu(struct request *rq);
	377
	378	/*
	379	* Driver command data is immediately after the request. So subtract request
	380	* size to get back to the original request, add request size to get the PDU.
	381	*/
	382	static inline struct request blk_mq_rq_from_pdu(void pdu)
	383	{
	384	return pdu - sizeof(struct request);
	385	}
	386	static inline void blk_mq_rq_to_pdu(struct request rq)
	387	{
	388	return rq + 1;
	389	}
	390
	391	#define queue_for_each_hw_ctx(q, hctx, i) \
	392	for ((i) = 0; (i) < (q)->nr_hw_queues && \
	393	({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
	394
	395	#define hctx_for_each_ctx(hctx, ctx, i) \
	396	for ((i) = 0; (i) < (hctx)->nr_ctx && \
	397	({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
	398
	399	static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
	400	struct request *rq)
	401	{
	402	if (rq->tag != -1)
	403	return rq->tag \| (hctx->queue_num << BLK_QC_T_SHIFT);
	404
	405	return rq->internal_tag \| (hctx->queue_num << BLK_QC_T_SHIFT) \|
	406	BLK_QC_T_INTERNAL;
	407	}
	408
	409	static inline void blk_mq_cleanup_rq(struct request *rq)
	410	{
	411	if (rq->q->mq_ops->cleanup_rq)
	412	rq->q->mq_ops->cleanup_rq(rq);
	413	}
	414
	415	#endif