linux-imx

/* SPDX-License-Identifier: GPL-2.0 */

#ifndef BLK_STAT_H

#define BLK_STAT_H

​

#include <linux/kernel.h>

#include <linux/blkdev.h>

#include <linux/ktime.h>

#include <linux/rcupdate.h>

#include <linux/timer.h>

​

/**

 * struct blk_stat_callback - Block statistics callback.

 *

 * A &struct blk_stat_callback is associated with a &struct request_queue. While

 * @timer is active, that queue's request completion latencies are sorted into

 * buckets by @bucket_fn and added to a per-cpu buffer, @cpu_stat. When the

 * timer fires, @cpu_stat is flushed to @stat and @timer_fn is invoked.

 */

struct blk_stat_callback {

    /*

     * @list: RCU list of callbacks for a &struct request_queue.

     */

    struct list_head list;

​

    /**

     * @timer: Timer for the next callback invocation.

     */

    struct timer_list timer;

​

    /**

     * @cpu_stat: Per-cpu statistics buckets.

     */

    struct blk_rq_stat __percpu *cpu_stat;

​

    /**

     * @bucket_fn: Given a request, returns which statistics bucket it

     * should be accounted under. Return -1 for no bucket for this

     * request.

     */

    int (*bucket_fn)(const struct request *);

​

    /**

     * @buckets: Number of statistics buckets.

     */

    unsigned int buckets;

​

    /**

     * @stat: Array of statistics buckets.

     */

    struct blk_rq_stat *stat;

​

    /**

     * @fn: Callback function.

     */

    void (*timer_fn)(struct blk_stat_callback *);

​

    /**

     * @data: Private pointer for the user.

     */

    void *data;

​

    struct rcu_head rcu;

};