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| author | Ming Lei <ming.lei@redhat.com> | 2025-05-05 22:18:03 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-05-06 07:43:43 -0600 |
| commit | 78c271344b6f64ce24c845e54903e09928cf2061 (patch) | |
| tree | ab840a1787f17001734bd8c9f2f464f8101f2d10 /block/blk-sysfs.c | |
| parent | 7ed7fa561c357d1ff0d5938446662b2ea4b26bb3 (diff) | |
| download | linux-78c271344b6f64ce24c845e54903e09928cf2061.tar.gz linux-78c271344b6f64ce24c845e54903e09928cf2061.tar.bz2 linux-78c271344b6f64ce24c845e54903e09928cf2061.zip | |
block: move wbt_enable_default() out of queue freezing from sched ->exit()
scheduler's ->exit() is called with queue frozen and elevator lock is held, and
wbt_enable_default() can't be called with queue frozen, otherwise the
following lockdep warning is triggered:
#6 (&q->rq_qos_mutex){+.+.}-{4:4}:
#5 (&eq->sysfs_lock){+.+.}-{4:4}:
#4 (&q->elevator_lock){+.+.}-{4:4}:
#3 (&q->q_usage_counter(io)#3){++++}-{0:0}:
#2 (fs_reclaim){+.+.}-{0:0}:
#1 (&sb->s_type->i_mutex_key#3){+.+.}-{4:4}:
#0 (&q->debugfs_mutex){+.+.}-{4:4}:
Fix the issue by moving wbt_enable_default() out of bfq's exit(), and
call it from elevator_change_done().
Meantime add disk->rqos_state_mutex for covering wbt state change, which
matches the purpose more than ->elevator_lock.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250505141805.2751237-26-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-sysfs.c')
| -rw-r--r-- | block/blk-sysfs.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 741e607dfab6..01e0ead13278 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -560,7 +560,7 @@ static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page) ssize_t ret; struct request_queue *q = disk->queue; - mutex_lock(&q->elevator_lock); + mutex_lock(&disk->rqos_state_mutex); if (!wbt_rq_qos(q)) { ret = -EINVAL; goto out; @@ -573,7 +573,7 @@ static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page) ret = sysfs_emit(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000)); out: - mutex_unlock(&q->elevator_lock); + mutex_unlock(&disk->rqos_state_mutex); return ret; } @@ -593,7 +593,6 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, return -EINVAL; memflags = blk_mq_freeze_queue(q); - mutex_lock(&q->elevator_lock); rqos = wbt_rq_qos(q); if (!rqos) { @@ -618,11 +617,12 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, */ blk_mq_quiesce_queue(q); + mutex_lock(&disk->rqos_state_mutex); wbt_set_min_lat(q, val); + mutex_unlock(&disk->rqos_state_mutex); blk_mq_unquiesce_queue(q); out: - mutex_unlock(&q->elevator_lock); blk_mq_unfreeze_queue(q, memflags); return ret; @@ -871,9 +871,7 @@ int blk_register_queue(struct gendisk *disk) if (queue_is_mq(q)) elevator_set_default(q); - mutex_lock(&q->elevator_lock); wbt_enable_default(disk); - mutex_unlock(&q->elevator_lock); blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); |