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Date: Thu, 10 Nov 2016 15:19:15 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Keith Busch <keith.busch@intel.com>
Cc: Scott Bauer <scott.bauer@intel.com>,
        Christoph Hellwig <hch@infradead.org>,
        Sagi Grimberg <sagi@grimberg.me>,
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Subject: Re: [RFC PATCH 5/6] nvme: Add unlock_from_suspend
Message-ID: <20161110231915.GA16890@infradead.org>
References: <1477951099-3127-1-git-send-email-scott.bauer@intel.com>
 <1477951099-3127-6-git-send-email-scott.bauer@intel.com>
 <6a6a131a-09fe-4c7c-85a7-01149555e427@grimberg.me>
 <20161101135705.GA32697@infradead.org>
 <20161110230130.GA1923@sbauer-Z170X-UD5>
 <20161110232312.GG4929@localhost.localdomain>
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On Thu, Nov 10, 2016 at 06:23:12PM -0500, Keith Busch wrote:
> On Thu, Nov 10, 2016 at 04:01:31PM -0700, Scott Bauer wrote:
> > On Tue, Nov 01, 2016 at 06:57:05AM -0700, Christoph Hellwig wrote:
> > > blk_execute_rq_nowait is the API to use - blk_mq_insert_request isn't
> > > even exported.
> > 
> > I remember now, after I changed it to use rq_nowait, why we added this wrapper
> > function and used blk_mq_insert_request.
> > 
> > When we dispatch opal commands down to the controller we're doing so in an IRQ,
> > so if we use rq_nowait, we lockup.
> 
> In this case can we push the submission off to a work queue and use
> blk_mq_insert_rq_nowait?

That's what we have to do anyway to avoid taking irqsafe locks.
(and the function is blk_execute_rq_nowait)

From mboxrd@z Thu Jan  1 00:00:00 1970
From: hch@infradead.org (Christoph Hellwig)
Date: Thu, 10 Nov 2016 15:19:15 -0800
Subject: [RFC PATCH 5/6] nvme: Add unlock_from_suspend
In-Reply-To: <20161110232312.GG4929@localhost.localdomain>
References: <1477951099-3127-1-git-send-email-scott.bauer@intel.com>
 <1477951099-3127-6-git-send-email-scott.bauer@intel.com>
 <6a6a131a-09fe-4c7c-85a7-01149555e427@grimberg.me>
 <20161101135705.GA32697@infradead.org>
 <20161110230130.GA1923@sbauer-Z170X-UD5>
 <20161110232312.GG4929@localhost.localdomain>
Message-ID: <20161110231915.GA16890@infradead.org>

On Thu, Nov 10, 2016@06:23:12PM -0500, Keith Busch wrote:
> On Thu, Nov 10, 2016@04:01:31PM -0700, Scott Bauer wrote:
> > On Tue, Nov 01, 2016@06:57:05AM -0700, Christoph Hellwig wrote:
> > > blk_execute_rq_nowait is the API to use - blk_mq_insert_request isn't
> > > even exported.
> > 
> > I remember now, after I changed it to use rq_nowait, why we added this wrapper
> > function and used blk_mq_insert_request.
> > 
> > When we dispatch opal commands down to the controller we're doing so in an IRQ,
> > so if we use rq_nowait, we lockup.
> 
> In this case can we push the submission off to a work queue and use
> blk_mq_insert_rq_nowait?

That's what we have to do anyway to avoid taking irqsafe locks.
(and the function is blk_execute_rq_nowait)