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From: Bart Van Assche <bvanassche@acm.org>
To: John Garry <john.garry@huawei.com>,
	hare@suse.de, ming.lei@redhat.com, axboe@kernel.dk, hch@lst.de
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	pragalla@codeaurora.org, kashyap.desai@broadcom.com,
	yuyufen@huawei.com
Subject: Re: [RFC PATCH v3 3/3] blk-mq: Lockout tagset iterator when exiting elevator
Date: Tue, 9 Mar 2021 11:21:41 -0800	[thread overview]
Message-ID: <de3dec73-c8fc-d14f-5bbb-7023ccc6b57e@acm.org> (raw)
In-Reply-To: <f60dc68f-9206-2bfb-950e-cb312f1c4c8b@huawei.com>

On 3/9/21 9:47 AM, John Garry wrote:
> This does fall over if some tags are allocated without associated
> request queue, which I do not know exists.

The only tag allocation mechanism I know of is blk_mq_get_tag(). The
only blk_mq_get_tag() callers I know of are __blk_mq_alloc_request() and
blk_mq_alloc_request_hctx(). So I think all allocated tags are
associated with a request queue.

Regarding this patch series, I have shared the feedback I wanted to
share so I would appreciate it if someone else could also take a look.

Thanks,

Bart.

  reply	other threads:[~2021-03-09 19:22 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-05 15:14 [RFC PATCH v3 0/3] blk-mq: Avoid use-after-free for accessing old requests John Garry
2021-03-05 15:14 ` [RFC PATCH v3 1/3] blk-mq: Clean up references to old requests when freeing rqs John Garry
2021-03-06  2:52   ` Khazhy Kumykov
2021-03-08 11:18     ` John Garry
2021-03-06 18:13   ` Bart Van Assche
2021-03-08 10:37     ` John Garry
2021-03-05 15:14 ` [RFC PATCH v3 2/3] blk-mq: Freeze and quiesce all queues for tagset in elevator_exit() John Garry
2021-03-06  4:32   ` Bart Van Assche
2021-03-08 10:50     ` John Garry
2021-03-08 19:35       ` Bart Van Assche
2021-03-10 15:57   ` Bart Van Assche
2021-03-11  0:58   ` Ming Lei
2021-03-11  8:21     ` John Garry
2021-03-12 23:05       ` Bart Van Assche
2021-03-16 16:15         ` John Garry
2021-03-16 17:00           ` Bart Van Assche
2021-03-16 17:43             ` John Garry
2021-03-16 19:59               ` Bart Van Assche
2021-03-19 18:19                 ` John Garry
2021-03-19 18:32                   ` Bart Van Assche
2021-03-05 15:14 ` [RFC PATCH v3 3/3] blk-mq: Lockout tagset iterator when exiting elevator John Garry
2021-03-06  4:43   ` Bart Van Assche
2021-03-08 11:17     ` John Garry
2021-03-08 19:59       ` Bart Van Assche
2021-03-09 17:47         ` John Garry
2021-03-09 19:21           ` Bart Van Assche [this message]
2021-03-10  8:52             ` John Garry
2021-03-10 16:00               ` Bart Van Assche
2021-03-10 17:26                 ` John Garry
2021-03-18 10:26 ` [RFC PATCH v3 0/3] blk-mq: Avoid use-after-free for accessing old requests Shinichiro Kawasaki

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