/* 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;
#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_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 */

        HCTX_MAX_TYPES,
};

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 *,
                bool);
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;

#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);
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 {
        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);
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) |
                        BLK_QC_T_INTERNAL;
}

#endif