v4.19.13 snapshot.
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
new file mode 100644
index 0000000..1da59c1
--- /dev/null
+++ b/include/linux/blk-mq.h
@@ -0,0 +1,327 @@
+/* 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 int 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;
+ unsigned int nr_expired;
+
+ 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
+
+ /* Must be the last member - see also blk_mq_hw_ctx_size(). */
+ struct srcu_struct srcu[0];
+};
+
+struct blk_mq_tag_set {
+ unsigned int *mq_map;
+ const struct blk_mq_ops *ops;
+ unsigned int nr_hw_queues;
+ 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 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 void (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
+ bool);
+typedef void (busy_tag_iter_fn)(struct request *, void *, bool);
+typedef int (poll_fn)(struct blk_mq_hw_ctx *, unsigned int);
+typedef int (map_queues_fn)(struct blk_mq_tag_set *set);
+
+
+struct blk_mq_ops {
+ /*
+ * Queue request
+ */
+ queue_rq_fn *queue_rq;
+
+ /*
+ * 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;
+
+ softirq_done_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);
+
+ 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_SG_MERGE = 1 << 2,
+ 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);
+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 *);
+
+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);
+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);
+void 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_tag_set *set);
+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);
+
+/**
+ * blk_mq_mark_complete() - Set request state to complete
+ * @rq: request to set to complete state
+ *
+ * Returns true if request state was successfully set to complete. If
+ * successful, the caller is responsibile for seeing this request is ended, as
+ * blk_mq_complete_request will not work again.
+ */
+static inline bool blk_mq_mark_complete(struct request *rq)
+{
+ return cmpxchg(&rq->state, MQ_RQ_IN_FLIGHT, MQ_RQ_COMPLETE) ==
+ MQ_RQ_IN_FLIGHT;
+}
+
+/*
+ * 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)++)
+
+#endif