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/* 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;
unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER];
unsigned int numa_node;
unsigned int queue_num;
atomic_t nr_active;
unsigned int nr_expired;
struct hlist_node cpuhp_dead;
struct kobject kobj;
unsigned long poll_considered;
unsigned long poll_invoked;
unsigned long poll_success;
struct dentry *debugfs_dir;
struct dentry *sched_debugfs_dir;
/* Must be the last member - see also blk_mq_hw_ctx_size(). */
struct srcu_struct srcu[0];
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 */
struct blk_mq_tag_set {
* map[] holds ctx -> hctx mappings, one map exists for each 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.
struct blk_mq_queue_map map[HCTX_MAX_TYPES];
unsigned int nr_maps; /* nr entries in map[] */
const struct blk_mq_ops *ops;
unsigned int nr_hw_queues; /* nr hw queues across maps */
unsigned int queue_depth; /* max hw supported */
unsigned int reserved_tags;
unsigned int cmd_size; /* per-request extra data */
int numa_node;
unsigned int timeout;
unsigned int flags; /* BLK_MQ_F_* */
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 *,
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 *);
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);
* If set, returns whether or not this queue currently is busy
busy_fn *busy;
map_queues_fn *map_queues;
* Used by the debugfs implementation to show driver-specific
* information about a request.
void (*show_rq)(struct seq_file *m, struct request *rq);
enum {
BLK_MQ_F_NO_SCHED = 1 << 6,
#define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
#define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
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);
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);
int blk_mq_register_dev(struct device *, struct request_queue *);
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 {
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);
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_add_to_requeue_list(struct request *rq, bool at_head,
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);
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_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) |