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>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>,
"tj@kernel.org" <tj@kernel.org>,
"jthumshirn@suse.de" <jthumshirn@suse.de>,
"oleksandr@natalenko.name" <oleksandr@natalenko.name>
Subject: Re: [PATCH V2 6/8] block: allow to allocate req with REQF_PREEMPT when queue is frozen
Date: Sat, 2 Sep 2017 10:52:54 +0800 [thread overview]
Message-ID: <20170902025253.GA20047@ming.t460p> (raw)
In-Reply-To: <1504296423.14386.62.camel@wdc.com>
On Fri, Sep 01, 2017 at 08:07:04PM +0000, Bart Van Assche wrote:
> On Sat, 2017-09-02 at 02:49 +0800, Ming Lei wrote:
> > + if ((flags & BLK_MQ_REQ_PREEMPT) && blk_queue_is_freezing(q))
> > + blk_queue_enter_live(q);
> > + else
> > + ret = blk_queue_enter(q, !(gfp_mask & __GFP_DIRECT_RECLAIM));
>
> Why did you repost this patch series without trying to reach an agreement
> about the approach?
>
> Anyway, because of the unsafe blk_queue_enter_live() call introduced by this
> patch, please add the following to the description of this patch whenever you
> repost it:
>
> NAK-ed-by: Bart Van Assche <bart.vanassche@wdc.com>
Did you take a look at the patch 7 or cover letter? In that patch,
if preempt freezing is on-progressing, any other freeze can't be
started at all, so that is definitely safe to use blk_queue_enter_live()
here, isn't it?
--
Ming
next prev parent reply other threads:[~2017-09-02 2:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-01 18:49 [PATCH V2 0/8] block/scsi: safe SCSI quiescing Ming Lei
2017-09-01 18:49 ` Ming Lei
2017-09-01 18:49 ` [PATCH V2 1/8] blk-mq: rename blk_mq_unfreeze_queue as blk_unfreeze_queue Ming Lei
2017-09-01 18:49 ` [PATCH V2 2/8] blk-mq: rename blk_mq_freeze_queue as blk_freeze_queue Ming Lei
2017-09-01 18:49 ` [PATCH V2 3/8] blk-mq: only run hw queues for blk-mq Ming Lei
2017-09-01 18:49 ` [PATCH V2 4/8] blk-mq: rename blk_mq_freeze_queue_wait as blk_freeze_queue_wait Ming Lei
2017-09-01 18:49 ` [PATCH V2 5/8] block: tracking request allocation with q_usage_counter Ming Lei
2017-09-01 18:49 ` [PATCH V2 6/8] block: allow to allocate req with REQF_PREEMPT when queue is frozen Ming Lei
2017-09-01 20:07 ` Bart Van Assche
2017-09-02 2:52 ` Ming Lei [this message]
2017-09-01 18:49 ` [PATCH V2 7/8] block: introduce preempt version of blk_[freeze|unfreeze]_queue Ming Lei
2017-09-01 18:49 ` [PATCH V2 8/8] SCSI: freeze block queue when SCSI device is put into quiesce Ming Lei
2017-09-02 7:12 ` [PATCH V2 0/8] block/scsi: safe SCSI quiescing Oleksandr Natalenko
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