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From: Mike Anderson <andmike@linux.vnet.ibm.com>
To: Mike Snitzer <snitzer@redhat.com>,
	dm-devel@redhat.com, Mike Christie <michaelc@cs.wisc.edu>,
	linux-scsi@vger.kernel.org
Subject: Re: [dm-devel] [PATCH v5] dm mpath: avoid call to blk_abort_queue by default
Date: Thu, 18 Nov 2010 12:39:55 -0800	[thread overview]
Message-ID: <20101118203954.GA6241@linux.vnet.ibm.com> (raw)
In-Reply-To: <20101118201841.GE30435@agk-dp.fab.redhat.com>

Alasdair G Kergon <agk@redhat.com> wrote:
> On Thu, Nov 18, 2010 at 03:07:33PM -0500, Mike Snitzer wrote:
> > It is expected that this race will be fixed in the near-term so it makes
> > little since to remove all associated code.  Providing control over the
> > call to blk_abort_queue() facilitates continued testing and future
> > flexibility to opt-in to lower latency path deactivation.  Opting to
> > enable this feature will emit a warning for the time being.
> 
> Ah, but then the *feature* keyword - which is only going to be needed
> temporarily until it's fixed - becomes a permanent part of the interface...
> 
> If it's broken, let's just disable it (#define-style) until it gets fixed.
> (And only if it doesn't get fixed in a reasonable amount of time, remove the
> code.)

I understand that if its broken that we could #define it out in dm or we
could #define the code in blk_abort_queue.

I believe the thought was that post addressing the race issue that
others may want control. As there maybe cases where the waking up of the
error_handler and a extra abort may not be wanted in all cases. 

-andmike
--
Michael Anderson
andmike@linux.vnet.ibm.com

      reply	other threads:[~2010-11-18 20:39 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-12  5:23 block_abort_queue (blk_abort_request) racing with scsi_request_fn Mike Anderson
2010-11-10  7:09 ` [dm-devel] " Mike Christie
2010-11-10  7:30   ` Mike Christie
2010-11-10 16:30     ` Mike Anderson
2010-11-10 21:16       ` Mike Christie
2010-11-12 17:54         ` Mike Anderson
2010-11-16 21:39           ` Mike Snitzer
2010-11-17 17:49             ` [dm-devel] " Mike Anderson
2010-11-17 21:55               ` Mike Snitzer
2010-11-18  4:40                 ` [PATCH v2] dm mpath: add feature flag to control call to blk_abort_queue Mike Snitzer
2010-11-18  7:20                   ` Mike Anderson
2010-11-18 15:48                     ` Mike Snitzer
2010-11-18 15:48                     ` [PATCH v3] " Mike Snitzer
2010-11-18 19:16                       ` (unknown), Mike Snitzer
2010-11-18 19:21                         ` Mike Snitzer
2010-11-18 19:19                       ` [PATCH v4] dm mpath: avoid call to blk_abort_queue by default Mike Snitzer
2010-11-18 20:07                         ` [PATCH v5] " Mike Snitzer
2010-11-18 20:18                           ` [dm-devel] " Alasdair G Kergon
2010-11-18 20:39                             ` Mike Anderson [this message]

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