From: ming.lei@redhat.com (Ming Lei)
Subject: [PATCH 2/5] blk-mq: introduce blk_mq_tagset_wait_completed_request()
Date: Tue, 23 Jul 2019 09:06:18 +0800 [thread overview]
Message-ID: <20190723010616.GC30776@ming.t460p> (raw)
In-Reply-To: <c2722892-9cbf-0747-58a8-91a99b72bc53@acm.org>
On Mon, Jul 22, 2019@08:25:07AM -0700, Bart Van Assche wrote:
> On 7/21/19 10:39 PM, Ming Lei wrote:
> > blk-mq may schedule to call queue's complete function on remote CPU via
> > IPI, but doesn't provide any way to synchronize the request's complete
> > fn.
> >
> > In some driver's EH(such as NVMe), hardware queue's resource may be freed &
> > re-allocated. If the completed request's complete fn is run finally after the
> > hardware queue's resource is released, kernel crash will be triggered.
> >
> > Prepare for fixing this kind of issue by introducing
> > blk_mq_tagset_wait_completed_request().
>
> An explanation is missing of why the block layer is modified to fix this
> instead of the NVMe driver.
The above commit log has explained that there isn't sync mechanism in
blk-mq wrt. request completion, and there might be similar issue in other
future drivers.
Thanks,
Ming
next prev parent reply other threads:[~2019-07-23 1:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 5:39 [PATCH 0/5] blk-mq: wait until completed req's complete fn is run Ming Lei
2019-07-22 5:39 ` [PATCH 1/5] blk-mq: introduce blk_mq_request_completed() Ming Lei
2019-07-23 20:26 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 2/5] blk-mq: introduce blk_mq_tagset_wait_completed_request() Ming Lei
2019-07-22 15:25 ` Bart Van Assche
2019-07-23 1:06 ` Ming Lei [this message]
2019-07-23 20:54 ` Bart Van Assche
2019-07-24 1:34 ` Ming Lei
2019-07-23 20:27 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 3/5] nvme: don't abort completed request in nvme_cancel_request Ming Lei
2019-07-22 15:27 ` Bart Van Assche
2019-07-22 23:22 ` Keith Busch
2019-07-23 0:07 ` Sagi Grimberg
2019-07-23 1:08 ` Ming Lei
2019-07-23 19:22 ` Bart Van Assche
2019-07-23 20:27 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 4/5] nvme: wait until all completed request's complete fn is called Ming Lei
2019-07-23 16:14 ` Dongli Zhang
2019-07-24 2:05 ` Ming Lei
2019-07-23 20:29 ` Sagi Grimberg
2019-07-24 1:43 ` Ming Lei
2019-07-22 5:39 ` [PATCH 5/5] blk-mq: remove blk_mq_complete_request_sync Ming Lei
2019-07-23 20:30 ` Sagi Grimberg
2019-07-22 23:27 ` [PATCH 0/5] blk-mq: wait until completed req's complete fn is run Bob Liu
2019-07-23 1:10 ` Ming Lei
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