From: Keith Busch <kbusch@kernel.org>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: hch@lst.de, ming.lei@redhat.com, axboe@kernel.dk,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
yukuai3@huawei.com, yi.zhang@huawei.com, yangerkun@huawei.com
Subject: Re: [PATCH] blk-mq: quiesce queue while reallocating hctxs
Date: Thu, 2 Mar 2023 18:24:21 -0700 [thread overview]
Message-ID: <ZAFMRUo9fdcJh/JD@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20230221092436.3570192-1-yukuai1@huaweicloud.com>
On Tue, Feb 21, 2023 at 05:24:36PM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> commit 8237c01f1696 ("blk-mq: use quiesced elevator switch when
> reinitializing queues") add quiesce queue while switching elevator,
> however, if old elevator is none, queue is still not quiesced. Hence
> reallocating hctxs can concurrent with run queue. Fix it by also
> quiesce queue in the beginning of __blk_mq_update_nr_hw_queues().
Is this actually fixing anything? The quiesced elevator switch was to prevent
use-after-free from an elevator being torn down, but if you are not switching
elevators, then what resource does quiescing protect?
next prev parent reply other threads:[~2023-03-03 1:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-21 9:24 Yu Kuai
2023-03-03 1:04 ` Yu Kuai
2023-03-03 1:24 ` Keith Busch [this message]
2023-03-03 2:21 ` Yu Kuai
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