#ifndef BLK_MQ_H
#define BLK_MQ_H

#include <linux/blkdev.h>

struct blk_mq_tags;

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

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     delayed_work;

        unsigned long           flags;          /* BLK_MQ_F_* flags */

        struct request_queue    *queue;
        unsigned int            queue_num;

        void                    *driver_data;

        unsigned int            nr_ctx;
        struct blk_mq_ctx       **ctxs;
        unsigned int            nr_ctx_map;
        unsigned long           *ctx_map;

        struct request          **rqs;
        struct list_head        page_list;
        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            queue_depth;
        unsigned int            numa_node;
        unsigned int            cmd_size;       /* per-request extra data */

        struct blk_mq_cpu_notifier      cpu_notifier;
        struct kobject          kobj;
};

struct blk_mq_reg {
        struct blk_mq_ops       *ops;
        unsigned int            nr_hw_queues;
        unsigned int            queue_depth;
        unsigned int            reserved_tags;
        unsigned int            cmd_size;       /* per-request extra data */
        int                     numa_node;
        unsigned int            timeout;
        unsigned int            flags;          /* BLK_MQ_F_* */
};

typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, struct request *);
typedef struct blk_mq_hw_ctx *(map_queue_fn)(struct request_queue *, const int);
typedef struct blk_mq_hw_ctx *(alloc_hctx_fn)(struct blk_mq_reg *,unsigned int);
typedef void (free_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
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);

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
         */
        rq_timed_out_fn         *timeout;

        softirq_done_fn         *complete;

        /*
         * Override for hctx allocations (should probably go)
         */
        alloc_hctx_fn           *alloc_hctx;
        free_hctx_fn            *free_hctx;

        /*
         * 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;
};

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_SHOULD_SORT    = 1 << 1,
        BLK_MQ_F_SHOULD_IPI     = 1 << 2,

        BLK_MQ_S_STOPPED        = 1 << 0,

        BLK_MQ_MAX_DEPTH        = 2048,
};

struct request_queue *blk_mq_init_queue(struct blk_mq_reg *, void *);
int blk_mq_register_disk(struct gendisk *);
void blk_mq_unregister_disk(struct gendisk *);
void blk_mq_init_commands(struct request_queue *, void (*init)(void *data, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data);

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_run_queues(struct request_queue *q, bool async);
void blk_mq_free_request(struct request *rq);
bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp);
struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw, gfp_t gfp);
struct request *blk_mq_rq_from_tag(struct request_queue *q, unsigned int tag);

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_reg *, unsigned int);
void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *, unsigned int);

bool blk_mq_end_io_partial(struct request *rq, int error,
                unsigned int nr_bytes);
static inline void blk_mq_end_io(struct request *rq, int error)
{
        bool done = !blk_mq_end_io_partial(rq, error, blk_rq_bytes(rq));
        BUG_ON(!done);
}

void blk_mq_complete_request(struct request *rq);

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_stopped_hw_queues(struct request_queue *q);

/*
 * 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);
}
static inline void *blk_mq_rq_to_pdu(struct request *rq)
{
        return (void *) rq + sizeof(*rq);
}

static inline struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx,
                                               unsigned int tag)
{
        return hctx->rqs[tag];
}

#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 queue_for_each_ctx(q, ctx, i)                                   \
        for ((i) = 0; (i) < (q)->nr_queues &&                           \
             ({ ctx = per_cpu_ptr((q)->queue_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)++)

#define blk_ctx_sum(q, sum)                                             \
({                                                                      \
        struct blk_mq_ctx *__x;                                         \
        unsigned int __ret = 0, __i;                                    \
                                                                        \
        queue_for_each_ctx((q), __x, __i)                               \
                __ret += sum;                                           \
        __ret;                                                          \
})

#endif