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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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5cf9c91ba9
Various places like I/O schedulers or the QOS infrastructure try to register debugfs files on demans, which can race with creating and removing the main queue debugfs directory. Use the existing debugfs_mutex to serialize all debugfs operations that rely on q->debugfs_dir or the directories hanging off it. To make the teardown code a little simpler declare all debugfs dentry pointers and not just the main one uncoditionally in blkdev.h. Move debugfs_mutex next to the dentries that it protects and document what it is used for. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220614074827.458955-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
227 lines
5.6 KiB
C
227 lines
5.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef RQ_QOS_H
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#define RQ_QOS_H
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#include <linux/kernel.h>
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#include <linux/blkdev.h>
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#include <linux/blk_types.h>
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#include <linux/atomic.h>
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#include <linux/wait.h>
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#include <linux/blk-mq.h>
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#include "blk-mq-debugfs.h"
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struct blk_mq_debugfs_attr;
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enum rq_qos_id {
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RQ_QOS_WBT,
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RQ_QOS_LATENCY,
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RQ_QOS_COST,
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RQ_QOS_IOPRIO,
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};
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struct rq_wait {
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wait_queue_head_t wait;
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atomic_t inflight;
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};
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struct rq_qos {
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struct rq_qos_ops *ops;
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struct request_queue *q;
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enum rq_qos_id id;
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struct rq_qos *next;
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#ifdef CONFIG_BLK_DEBUG_FS
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struct dentry *debugfs_dir;
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#endif
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};
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struct rq_qos_ops {
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void (*throttle)(struct rq_qos *, struct bio *);
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void (*track)(struct rq_qos *, struct request *, struct bio *);
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void (*merge)(struct rq_qos *, struct request *, struct bio *);
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void (*issue)(struct rq_qos *, struct request *);
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void (*requeue)(struct rq_qos *, struct request *);
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void (*done)(struct rq_qos *, struct request *);
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void (*done_bio)(struct rq_qos *, struct bio *);
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void (*cleanup)(struct rq_qos *, struct bio *);
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void (*queue_depth_changed)(struct rq_qos *);
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void (*exit)(struct rq_qos *);
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const struct blk_mq_debugfs_attr *debugfs_attrs;
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};
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struct rq_depth {
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unsigned int max_depth;
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int scale_step;
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bool scaled_max;
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unsigned int queue_depth;
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unsigned int default_depth;
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};
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static inline struct rq_qos *rq_qos_id(struct request_queue *q,
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enum rq_qos_id id)
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{
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struct rq_qos *rqos;
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for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
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if (rqos->id == id)
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break;
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}
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return rqos;
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}
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static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
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{
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return rq_qos_id(q, RQ_QOS_WBT);
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}
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static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
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{
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return rq_qos_id(q, RQ_QOS_LATENCY);
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}
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static inline void rq_wait_init(struct rq_wait *rq_wait)
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{
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atomic_set(&rq_wait->inflight, 0);
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init_waitqueue_head(&rq_wait->wait);
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}
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static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
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{
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/*
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* No IO can be in-flight when adding rqos, so freeze queue, which
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* is fine since we only support rq_qos for blk-mq queue.
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*
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* Reuse ->queue_lock for protecting against other concurrent
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* rq_qos adding/deleting
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*/
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blk_mq_freeze_queue(q);
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spin_lock_irq(&q->queue_lock);
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rqos->next = q->rq_qos;
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q->rq_qos = rqos;
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spin_unlock_irq(&q->queue_lock);
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blk_mq_unfreeze_queue(q);
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if (rqos->ops->debugfs_attrs) {
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mutex_lock(&q->debugfs_mutex);
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blk_mq_debugfs_register_rqos(rqos);
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mutex_unlock(&q->debugfs_mutex);
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}
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}
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static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
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{
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struct rq_qos **cur;
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/*
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* See comment in rq_qos_add() about freezing queue & using
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* ->queue_lock.
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*/
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blk_mq_freeze_queue(q);
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spin_lock_irq(&q->queue_lock);
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for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
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if (*cur == rqos) {
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*cur = rqos->next;
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break;
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}
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}
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spin_unlock_irq(&q->queue_lock);
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blk_mq_unfreeze_queue(q);
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mutex_lock(&q->debugfs_mutex);
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blk_mq_debugfs_unregister_rqos(rqos);
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mutex_unlock(&q->debugfs_mutex);
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}
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typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
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typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
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void rq_qos_wait(struct rq_wait *rqw, void *private_data,
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acquire_inflight_cb_t *acquire_inflight_cb,
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cleanup_cb_t *cleanup_cb);
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bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
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bool rq_depth_scale_up(struct rq_depth *rqd);
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bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
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bool rq_depth_calc_max_depth(struct rq_depth *rqd);
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void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
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void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
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void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
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void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
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void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
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void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
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void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
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void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
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void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
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static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
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{
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if (q->rq_qos)
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__rq_qos_cleanup(q->rq_qos, bio);
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}
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static inline void rq_qos_done(struct request_queue *q, struct request *rq)
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{
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if (q->rq_qos)
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__rq_qos_done(q->rq_qos, rq);
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}
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static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
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{
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if (q->rq_qos)
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__rq_qos_issue(q->rq_qos, rq);
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}
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static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
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{
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if (q->rq_qos)
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__rq_qos_requeue(q->rq_qos, rq);
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}
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static inline void rq_qos_done_bio(struct bio *bio)
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{
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if (bio->bi_bdev && (bio_flagged(bio, BIO_QOS_THROTTLED) ||
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bio_flagged(bio, BIO_QOS_MERGED))) {
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struct request_queue *q = bdev_get_queue(bio->bi_bdev);
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if (q->rq_qos)
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__rq_qos_done_bio(q->rq_qos, bio);
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}
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}
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static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
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{
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if (q->rq_qos) {
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bio_set_flag(bio, BIO_QOS_THROTTLED);
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__rq_qos_throttle(q->rq_qos, bio);
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}
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}
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static inline void rq_qos_track(struct request_queue *q, struct request *rq,
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struct bio *bio)
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{
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if (q->rq_qos)
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__rq_qos_track(q->rq_qos, rq, bio);
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}
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static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
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struct bio *bio)
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{
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if (q->rq_qos) {
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bio_set_flag(bio, BIO_QOS_MERGED);
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__rq_qos_merge(q->rq_qos, rq, bio);
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}
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}
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static inline void rq_qos_queue_depth_changed(struct request_queue *q)
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{
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if (q->rq_qos)
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__rq_qos_queue_depth_changed(q->rq_qos);
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}
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void rq_qos_exit(struct request_queue *);
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#endif
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