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Diffstat (limited to '')
| -rw-r--r-- | include/linux/blk-mq.h | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h new file mode 100644 index 000000000..f8ea27423 --- /dev/null +++ b/include/linux/blk-mq.h @@ -0,0 +1,598 @@ +/* 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 { + /** @lock: Protects the dispatch list. */ + spinlock_t lock; + /** + * @dispatch: Used for requests that are ready to be + * dispatched to the hardware but for some reason (e.g. lack of + * resources) could not be sent to the hardware. As soon as the + * driver can send new requests, requests at this list will + * be sent first for a fairer dispatch. + */ + struct list_head dispatch; + /** + * @state: BLK_MQ_S_* flags. Defines the state of the hw + * queue (active, scheduled to restart, stopped). + */ + unsigned long state; + } ____cacheline_aligned_in_smp; + + /** + * @run_work: Used for scheduling a hardware queue run at a later time. + */ + struct delayed_work run_work; + /** @cpumask: Map of available CPUs where this hctx can run. */ + cpumask_var_t cpumask; + /** + * @next_cpu: Used by blk_mq_hctx_next_cpu() for round-robin CPU + * selection from @cpumask. + */ + int next_cpu; + /** + * @next_cpu_batch: Counter of how many works left in the batch before + * changing to the next CPU. + */ + int next_cpu_batch; + + /** @flags: BLK_MQ_F_* flags. Defines the behaviour of the queue. */ + unsigned long flags; + + /** + * @sched_data: Pointer owned by the IO scheduler attached to a request + * queue. It's up to the IO scheduler how to use this pointer. + */ + void *sched_data; + /** + * @queue: Pointer to the request queue that owns this hardware context. + */ + struct request_queue *queue; + /** @fq: Queue of requests that need to perform a flush operation. */ + struct blk_flush_queue *fq; + + /** + * @driver_data: Pointer to data owned by the block driver that created + * this hctx + */ + void *driver_data; + + /** + * @ctx_map: Bitmap for each software queue. If bit is on, there is a + * pending request in that software queue. + */ + struct sbitmap ctx_map; + + /** + * @dispatch_from: Software queue to be used when no scheduler was + * selected. + */ + struct blk_mq_ctx *dispatch_from; + /** + * @dispatch_busy: Number used by blk_mq_update_dispatch_busy() to + * decide if the hw_queue is busy using Exponential Weighted Moving + * Average algorithm. + */ + unsigned int dispatch_busy; + + /** @type: HCTX_TYPE_* flags. Type of hardware queue. */ + unsigned short type; + /** @nr_ctx: Number of software queues. */ + unsigned short nr_ctx; + /** @ctxs: Array of software queues. */ + struct blk_mq_ctx **ctxs; + + /** @dispatch_wait_lock: Lock for dispatch_wait queue. */ + spinlock_t dispatch_wait_lock; + /** + * @dispatch_wait: Waitqueue to put requests when there is no tag + * available at the moment, to wait for another try in the future. + */ + wait_queue_entry_t dispatch_wait; + + /** + * @wait_index: Index of next available dispatch_wait queue to insert + * requests. + */ + atomic_t wait_index; + + /** + * @tags: Tags owned by the block driver. A tag at this set is only + * assigned when a request is dispatched from a hardware queue. + */ + struct blk_mq_tags *tags; + /** + * @sched_tags: Tags owned by I/O scheduler. If there is an I/O + * scheduler associated with a request queue, a tag is assigned when + * that request is allocated. Else, this member is not used. + */ + struct blk_mq_tags *sched_tags; + + /** @queued: Number of queued requests. */ + unsigned long queued; + /** @run: Number of dispatched requests. */ + unsigned long run; +#define BLK_MQ_MAX_DISPATCH_ORDER 7 + /** @dispatched: Number of dispatch requests by queue. */ + unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER]; + + /** @numa_node: NUMA node the storage adapter has been connected to. */ + unsigned int numa_node; + /** @queue_num: Index of this hardware queue. */ + unsigned int queue_num; + + /** + * @nr_active: Number of active requests. Only used when a tag set is + * shared across request queues. + */ + atomic_t nr_active; + /** + * @elevator_queued: Number of queued requests on hctx. + */ + atomic_t elevator_queued; + + /** @cpuhp_online: List to store request if CPU is going to die */ + struct hlist_node cpuhp_online; + /** @cpuhp_dead: List to store request if some CPU die. */ + struct hlist_node cpuhp_dead; + /** @kobj: Kernel object for sysfs. */ + struct kobject kobj; + + /** @poll_considered: Count times blk_poll() was called. */ + unsigned long poll_considered; + /** @poll_invoked: Count how many requests blk_poll() polled. */ + unsigned long poll_invoked; + /** @poll_success: Count how many polled requests were completed. */ + unsigned long poll_success; + +#ifdef CONFIG_BLK_DEBUG_FS + /** + * @debugfs_dir: debugfs directory for this hardware queue. Named + * as cpu<cpu_number>. + */ + struct dentry *debugfs_dir; + /** @sched_debugfs_dir: debugfs directory for the scheduler. */ + struct dentry *sched_debugfs_dir; +#endif + + /** + * @hctx_list: if this hctx is not in use, this is an entry in + * q->unused_hctx_list. + */ + struct list_head hctx_list; + + /** + * @srcu: Sleepable RCU. Use as lock when type of the hardware queue is + * blocking (BLK_MQ_F_BLOCKING). Must be the last member - see also + * blk_mq_hw_ctx_size(). + */ + struct srcu_struct srcu[]; +}; + +/** + * struct blk_mq_queue_map - Map software queues to hardware queues + * @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 - Type of hardware queue + * @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: Number of types of hctx. + */ +enum hctx_type { + HCTX_TYPE_DEFAULT, + HCTX_TYPE_READ, + HCTX_TYPE_POLL, + + 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. + * @active_queues_shared_sbitmap: + * number of active request queues per tag set. + * @__bitmap_tags: A shared tags sbitmap, used over all hctx's + * @__breserved_tags: + * A shared reserved tags sbitmap, used over all hctx's + * @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; + atomic_t active_queues_shared_sbitmap; + + struct sbitmap_queue __bitmap_tags; + struct sbitmap_queue __breserved_tags; + struct blk_mq_tags **tags; + + struct mutex tag_list_lock; + struct list_head tag_list; +}; + +/** + * struct blk_mq_queue_data - Data about a request inserted in a queue + * + * @rq: Request pointer. + * @last: If it is the last request in the queue. + */ +struct blk_mq_queue_data { + struct request *rq; + bool last; +}; + +typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *, + bool); +typedef bool (busy_tag_iter_fn)(struct request *, void *, bool); + +/** + * struct blk_mq_ops - Callback functions that implements block driver + * behaviour. + */ +struct blk_mq_ops { + /** + * @queue_rq: Queue a new request from block IO. + */ + blk_status_t (*queue_rq)(struct blk_mq_hw_ctx *, + const struct blk_mq_queue_data *); + + /** + * @commit_rqs: 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). + */ + void (*commit_rqs)(struct blk_mq_hw_ctx *); + + /** + * @get_budget: 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. + */ + bool (*get_budget)(struct request_queue *); + + /** + * @put_budget: Release the reserved budget. + */ + void (*put_budget)(struct request_queue *); + + /** + * @timeout: Called on request timeout. + */ + enum blk_eh_timer_return (*timeout)(struct request *, bool); + + /** + * @poll: Called to poll for completion of a specific tag. + */ + int (*poll)(struct blk_mq_hw_ctx *); + + /** + * @complete: Mark the request as complete. + */ + void (*complete)(struct request *); + + /** + * @init_hctx: Called when the block layer side of a hardware queue has + * been set up, allowing the driver to allocate/init matching + * structures. + */ + int (*init_hctx)(struct blk_mq_hw_ctx *, void *, unsigned int); + /** + * @exit_hctx: Ditto for exit/teardown. + */ + void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int); + + /** + * @init_request: 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. + */ + int (*init_request)(struct blk_mq_tag_set *set, struct request *, + unsigned int, unsigned int); + /** + * @exit_request: Ditto for exit/teardown. + */ + void (*exit_request)(struct blk_mq_tag_set *set, struct request *, + unsigned int); + + /** + * @initialize_rq_fn: Called from inside blk_get_request(). + */ + void (*initialize_rq_fn)(struct request *rq); + + /** + * @cleanup_rq: Called before freeing one request which isn't completed + * yet, and usually for freeing the driver private data. + */ + void (*cleanup_rq)(struct request *); + + /** + * @busy: If set, returns whether or not this queue currently is busy. + */ + bool (*busy)(struct request_queue *); + + /** + * @map_queues: This allows drivers specify their own queue mapping by + * overriding the setup-time function that builds the mq_map. + */ + int (*map_queues)(struct blk_mq_tag_set *set); + +#ifdef CONFIG_BLK_DEBUG_FS + /** + * @show_rq: 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_QUEUE_SHARED = 1 << 1, + /* + * Set when this device requires underlying blk-mq device for + * completing IO: + */ + BLK_MQ_F_STACKING = 1 << 2, + BLK_MQ_F_TAG_HCTX_SHARED = 1 << 3, + 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, + + /* hw queue is inactive after all its CPUs become offline */ + BLK_MQ_S_INACTIVE = 3, + + 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_queue_data(struct blk_mq_tag_set *set, + void *queuedata); +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_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), + /* set RQF_PM */ + BLK_MQ_REQ_PM = (__force blk_mq_req_flags_t)(1 << 2), +}; + +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; +} + +/** + * blk_mq_rq_state() - read the current MQ_RQ_* state of a request + * @rq: target request. + */ +static inline enum mq_rq_state blk_mq_rq_state(struct request *rq) +{ + return READ_ONCE(rq->state); +} + +static inline int blk_mq_request_started(struct request *rq) +{ + return blk_mq_rq_state(rq) != MQ_RQ_IDLE; +} + +static inline int blk_mq_request_completed(struct request *rq) +{ + return blk_mq_rq_state(rq) == MQ_RQ_COMPLETE; +} + +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); +void blk_mq_complete_request(struct request *rq); +bool blk_mq_complete_request_remote(struct request *rq); +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); +void 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_delay_run_hw_queues(struct request_queue *q, unsigned long msecs); +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); + +bool __blk_should_fake_timeout(struct request_queue *q); +static inline bool blk_should_fake_timeout(struct request_queue *q) +{ + if (IS_ENABLED(CONFIG_FAIL_IO_TIMEOUT) && + test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) + return __blk_should_fake_timeout(q); + return false; +} + +/** + * blk_mq_rq_from_pdu - cast a PDU to a request + * @pdu: the PDU (Protocol Data Unit) to be casted + * + * Return: request + * + * Driver command data is immediately after the request. So subtract request + * size to get back to the original request. + */ +static inline struct request *blk_mq_rq_from_pdu(void *pdu) +{ + return pdu - sizeof(struct request); +} + +/** + * blk_mq_rq_to_pdu - cast a request to a PDU + * @rq: the request to be casted + * + * Return: pointer to the PDU + * + * Driver command data is immediately after the request. So add request to get + * the PDU. + */ +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); +} + +blk_qc_t blk_mq_submit_bio(struct bio *bio); + +#endif |