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From: John Garry <john.garry@huawei.com>
To: Bart Van Assche <bvanassche@acm.org>, <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: Wed, 10 Mar 2021 08:52:15 +0000	[thread overview]
Message-ID: <b4e39d48-3524-ac34-c20e-0dadcf15e3d6@huawei.com> (raw)
In-Reply-To: <de3dec73-c8fc-d14f-5bbb-7023ccc6b57e@acm.org>

On 09/03/2021 19:21, Bart Van Assche wrote:
> 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.
> 

Hi Bart,

> 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.
> 

ok, good.

> 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.
> 

So I can incorporate any changes and suggestions so far and send a 
non-RFC version - that may get more attention if none extra comes.

As mentioned on the cover letter, if patch 2+3/3 are accepted, then 
patch 1/3 could be simplified. But I plan to leave as is.

BTW, any issue with putting your suggested-by on patch 2/3?

Thanks,
John


  reply	other threads:[~2021-03-10  8:55 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
2021-03-10  8:52             ` John Garry [this message]
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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