diff options
| author | Julian Sun <sunjunchao2870@gmail.com> | 2025-08-12 23:42:57 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-08-13 05:33:48 -0600 |
| commit | 8f5845e0743bf3512b71b3cb8afe06c192d6acc4 (patch) | |
| tree | ec5ada88b5f824c5b1d87286405eb817bbbf177f | |
| parent | f7a2e1c08727384cde1c686dd57172f99b5f2e6e (diff) | |
block: restore default wbt enablement
The commit 245618f8e45f ("block: protect wbt_lat_usec using
q->elevator_lock") protected wbt_enable_default() with
q->elevator_lock; however, it also placed wbt_enable_default()
before blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);, resulting
in wbt failing to be enabled.
Moreover, the protection of wbt_enable_default() by q->elevator_lock
was removed in commit 78c271344b6f ("block: move wbt_enable_default()
out of queue freezing from sched ->exit()"), so we can directly fix
this issue by placing wbt_enable_default() after
blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);.
Additionally, this issue also causes the inability to read the
wbt_lat_usec file, and the scenario is as follows:
root@q:/sys/block/sda/queue# cat wbt_lat_usec
cat: wbt_lat_usec: Invalid argument
root@q:/data00/sjc/linux# ls /sys/kernel/debug/block/sda/rqos
cannot access '/sys/kernel/debug/block/sda/rqos': No such file or directory
root@q:/data00/sjc/linux# find /sys -name wbt
/sys/kernel/debug/tracing/events/wbt
After testing with this patch, wbt can be enabled normally.
Signed-off-by: Julian Sun <sunjunchao@bytedance.com>
Cc: stable@vger.kernel.org
Fixes: 245618f8e45f ("block: protect wbt_lat_usec using q->elevator_lock")
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250812154257.57540-1-sunjunchao@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-sysfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index c5cf79a20842..4a7f1a349998 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -902,9 +902,9 @@ int blk_register_queue(struct gendisk *disk) if (queue_is_mq(q)) elevator_set_default(q); - wbt_enable_default(disk); blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); + wbt_enable_default(disk); /* Now everything is ready and send out KOBJ_ADD uevent */ kobject_uevent(&disk->queue_kobj, KOBJ_ADD); |