From: Ming Lei <ming.lei@redhat.com>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
"jthumshirn@suse.de" <jthumshirn@suse.de>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"oleksandr@natalenko.name" <oleksandr@natalenko.name>,
"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>,
"tj@kernel.org" <tj@kernel.org>
Subject: Re: [PATCH V3 7/8] block: allow to allocate req with REQF_PREEMPT when queue is preempt frozen
Date: Sat, 9 Sep 2017 15:21:11 +0800 [thread overview]
Message-ID: <20170909072105.GA26081@ming.t460p> (raw)
In-Reply-To: <1504891695.1665.5.camel@wdc.com>
On Fri, Sep 08, 2017 at 05:28:16PM +0000, Bart Van Assche wrote:
> On Fri, 2017-09-08 at 11:08 +0800, Ming Lei wrote:
> > Looks I replied or clarified all your questions/comments on this
> > patchset.
>
> No, you have not addressed all my comments, you know that you have not
> addressed all my comments so you should not have written that you have
I do not know.
> addressed all my comments. This patch series not only introduces ugly
> changes in the request queue freeze mechanism but it also introduces an
> unacceptable race condition between blk_get_request() and request queue
> cleanup.
So what is the race? Could you reply in original thread?
>
> BTW, you don't have to spend more time on this patch series. I have
> implemented an alternative and much cleaner approach to fix SCSI device
> suspend. I'm currently testing that patch series.
You do not understand the issue at all, it is not only related with
suspend. Please take a look at scsi_execute(), each request run
via scsi_execute() need to be dispatched successfully even when
SCSI device is quiesced.
--
Ming
next prev parent reply other threads:[~2017-09-09 7:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-02 13:08 [PATCH V3 0/8] block/scsi: safe SCSI quiescing Ming Lei
2017-09-02 13:08 ` [PATCH V3 1/8] blk-mq: rename blk_mq_unfreeze_queue as blk_unfreeze_queue Ming Lei
2017-09-02 13:08 ` [PATCH V3 2/8] blk-mq: rename blk_mq_freeze_queue as blk_freeze_queue Ming Lei
2017-09-02 13:08 ` [PATCH V3 3/8] blk-mq: only run hw queues for blk-mq Ming Lei
2017-09-02 13:08 ` [PATCH V3 4/8] blk-mq: rename blk_mq_freeze_queue_wait as blk_freeze_queue_wait Ming Lei
2017-09-02 13:08 ` [PATCH V3 5/8] block: tracking request allocation with q_usage_counter Ming Lei
2017-09-02 13:08 ` [PATCH V3 6/8] block: introduce preempt version of blk_[freeze|unfreeze]_queue Ming Lei
2017-09-04 15:21 ` Bart Van Assche
2017-09-04 15:21 ` Bart Van Assche
2017-09-04 16:20 ` Ming Lei
2017-09-02 13:08 ` [PATCH V3 7/8] block: allow to allocate req with REQF_PREEMPT when queue is preempt frozen Ming Lei
2017-09-02 13:12 ` Ming Lei
2017-09-04 4:13 ` Bart Van Assche
2017-09-04 4:13 ` Bart Van Assche
2017-09-04 7:16 ` Ming Lei
2017-09-04 15:40 ` Bart Van Assche
2017-09-04 15:40 ` Bart Van Assche
2017-09-04 16:08 ` Ming Lei
2017-09-04 16:18 ` Bart Van Assche
2017-09-04 16:18 ` Bart Van Assche
2017-09-04 16:28 ` Ming Lei
2017-09-05 1:40 ` Bart Van Assche
2017-09-05 1:40 ` Bart Van Assche
2017-09-05 2:23 ` Ming Lei
2017-09-08 3:08 ` Ming Lei
2017-09-08 17:28 ` Bart Van Assche
2017-09-08 17:28 ` Bart Van Assche
2017-09-09 7:21 ` Ming Lei [this message]
2017-09-02 13:08 ` [PATCH V3 8/8] SCSI: preempt freeze block queue when SCSI device is put into quiesce Ming Lei
2017-09-02 14:47 ` [PATCH V3 0/8] block/scsi: safe SCSI quiescing Oleksandr Natalenko
2017-09-02 14:47 ` Oleksandr Natalenko
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