From: Ming Lei <ming.lei@redhat.com>
To: Chao Leng <lengchao@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, Yi Zhang <yi.zhang@redhat.com>,
Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH 1/2] nvme: make NVMe freeze API reliably
Date: Tue, 6 Sep 2022 16:45:05 +0800 [thread overview]
Message-ID: <YxcIkV2slhTR9MHX@T590> (raw)
In-Reply-To: <e2568bdd-a3cb-7a94-8018-d1468f3dcdd4@huawei.com>
On Thu, Aug 25, 2022 at 06:02:33PM +0800, Chao Leng wrote:
>
>
> On 2022/8/21 16:47, Ming Lei wrote:
> > From: Keith Busch <kbusch@kernel.org>
> >
> > In some corner cases[1], freeze wait and unfreeze API may be called on
> > unfrozen queue, add one per-ns flag of NVME_NS_FREEZE to make these
> > freeze APIs more reliably, then this kind of issues can be avoided.
> > And similar approach has been applied on stopping/quiescing nvme queues.
> This leads to another problem: the process that needs to be
> in the frozen state is not actually frozen.
> It's not safe.
The flag is just to control if queue wait is needed, blk_mq_freeze_queue_wait
can be done only the flag is set. Not sure how it isn't safe.
Meantime calling blk_mq_freeze_queue_wait() on queue not being started
to freeze is usually a bug, and I think WARN_ON_ONCE() can be added
in nvme_wait_freeze().
Thanks,
Ming
next prev parent reply other threads:[~2022-09-06 8:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-21 8:47 [PATCH 0/2] nvme: make NVMe freeze API reliably Ming Lei
2022-08-21 8:47 ` [PATCH 1/2] " Ming Lei
2022-08-24 11:15 ` Hannes Reinecke
2022-08-24 14:07 ` Keith Busch
2022-08-25 10:02 ` Chao Leng
2022-09-06 4:49 ` Christoph Hellwig
2022-09-06 8:45 ` Ming Lei [this message]
2022-09-06 9:32 ` Chao Leng
2022-09-07 0:33 ` Ming Lei
2022-09-07 1:18 ` Chao Leng
2022-09-07 2:06 ` Ming Lei
2022-09-07 5:58 ` Chao Leng
2022-08-28 14:37 ` Sagi Grimberg
2022-08-21 8:47 ` [PATCH 2/2] nvme-pci: don't wait freeze during resetting Ming Lei
2022-08-25 10:05 ` Chao Leng
2022-08-25 11:34 ` Ming Lei
2022-08-25 13:42 ` Keith Busch
2022-08-25 14:15 ` Ming Lei
2022-08-26 1:27 ` Chao Leng
2022-08-28 14:37 ` Sagi Grimberg
2022-09-06 4:49 ` Christoph Hellwig
2022-08-24 11:57 ` [PATCH 0/2] nvme: make NVMe freeze API reliably Yi Zhang
2022-09-19 14:52 ` Christoph Hellwig
2022-09-20 0:51 ` Ming Lei
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