#ifndef BLK_MQ_H
#define BLK_MQ_H

#include <linux/blkdev.h>

struct blk_mq_tags;
struct blk_flush_queue;

struct blk_mq_cpu_notifier {
        struct list_head list;
        void *data;
        int (*notify)(void *data, unsigned long action, unsigned int cpu);
};

struct blk_mq_ctxmap {
        unsigned int size;
        unsigned int bits_per_word;
        struct blk_align_bitmap *map;
};

struct blk_mq_hw_ctx {
        struct {
                spinlock_t              lock;
                struct list_head        dispatch;
        } ____cacheline_aligned_in_smp;

        unsigned long           state;          /* BLK_MQ_S_* flags */
        struct delayed_work     run_work;
        struct delayed_work     delay_work;
        cpumask_var_t           cpumask;
        int                     next_cpu;
        int                     next_cpu_batch;

        unsigned long           flags;          /* BLK_MQ_F_* flags */

        struct request_queue    *queue;
        struct blk_flush_queue  *fq;

        void                    *driver_data;

        struct blk_mq_ctxmap    ctx_map;

        unsigned int            nr_ctx;
        struct blk_mq_ctx       **ctxs;

        atomic_t                wait_index;

        struct blk_mq_tags      *tags;

        unsigned long           queued;
        unsigned long           run;
#define BLK_MQ_MAX_DISPATCH_ORDER       10
        unsigned long           dispatched[BLK_MQ_MAX_DISPATCH_ORDER];

        unsigned int            numa_node;
        unsigned int            queue_num;

        atomic_t                nr_active;

        struct blk_mq_cpu_notifier      cpu_notifier;
        struct kobject          kobj;

        unsigned long           poll_invoked;
        unsigned long           poll_success;
};

struct blk_mq_tag_set {
        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;
        struct list_head *list;
        bool last;
};

typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *);
typedef struct blk_mq_hw_ctx *(map_queue_fn)(struct request_queue *, const int);
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)(void *, struct request *, unsigned int,
                unsigned int, unsigned int);
typedef void (exit_request_fn)(void *, struct request *, unsigned int,
                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);


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

        /*
         * Map to specific hardware queue
         */
        map_queue_fn            *map_queue;

        /*
         * 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;
};

enum {
        BLK_MQ_RQ_QUEUE_OK      = 0,    /* queued fine */
        BLK_MQ_RQ_QUEUE_BUSY    = 1,    /* requeue IO for later */
        BLK_MQ_RQ_QUEUE_ERROR   = 2,    /* end IO with error */

        BLK_MQ_F_SHOULD_MERGE   = 1 << 0,
        BLK_MQ_F_TAG_SHARED     = 1 << 1,
        BLK_MQ_F_SG_MERGE       = 1 << 2,
        BLK_MQ_F_DEFER_ISSUE    = 1 << 4,
        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_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_disk(struct gendisk *);
void blk_mq_unregister_disk(struct gendisk *);

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

enum {
        BLK_MQ_REQ_NOWAIT       = (1 << 0), /* return when out of requests */
        BLK_MQ_REQ_RESERVED     = (1 << 1), /* allocate from reserved pool */
};

struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
                unsigned int flags);
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);
struct cpumask *blk_mq_tags_cpumask(struct blk_mq_tags *tags);

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;
}

struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_index);
struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set *, unsigned int, int);

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

void blk_mq_requeue_request(struct request *rq);
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head);
void blk_mq_cancel_requeue_work(struct request_queue *q);
void blk_mq_kick_requeue_list(struct request_queue *q);
void blk_mq_abort_requeue_list(struct request_queue *q);
void blk_mq_complete_request(struct request *rq, int error);

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_queues(struct request_queue *q, bool async);
void blk_mq_run_hw_queues(struct request_queue *q, bool async);
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags, 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_mq_freeze_queue_start(struct request_queue *q);

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

/*
 * 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