From: Yu Kuai <yukuai3@huawei.com>
To: <tj@kernel.org>, <axboe@kernel.dk>, <bo.liu@linux.alibaba.com>
Cc: <cgroups@vger.kernel.org>, <linux-block@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <yukuai3@huawei.com>,
<yi.zhang@huawei.com>
Subject: [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
Date: Thu, 5 Aug 2021 20:46:45 +0800 [thread overview]
Message-ID: <20210805124645.543797-1-yukuai3@huawei.com> (raw)
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: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
block/blk-iolatency.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 81be0096411d..d8b0d8bd132b 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -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);
}
--
2.31.1
next reply other threads:[~2021-08-05 12:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 12:46 Yu Kuai [this message]
2021-08-05 17:17 ` [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() Tejun Heo
2021-08-05 17:18 ` Jens Axboe
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