Commit 8d75d0ef authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe

blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()

If queue is dying while iolatency_set_limit() is in progress,
blk_get_queue() won't increment the refcount of the queue. However,
blk_put_queue() will still decrement the refcount later, which will
cause the refcout to be unbalanced.

Thus error out in such case to fix the problem.

Fixes: 8c772a9b ("blk-iolatency: fix IO hang due to negative inflight counter")
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210805124645.543797-1-yukuai3@huawei.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent cc396d27
......@@ -833,7 +833,11 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
enable = iolatency_set_min_lat_nsec(blkg, lat_val);
if (enable) {
WARN_ON_ONCE(!blk_get_queue(blkg->q));
if (!blk_get_queue(blkg->q)) {
ret = -ENODEV;
goto out;
}
blkg_get(blkg);
}
......
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