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Date: Sat, 8 Mar 2014 22:29:46 -0500
From: Mike Snitzer <snitzer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Hannes Reinecke <hare@suse.de>, Mike Snitzer <snitzer@gmail.com>,
        Christoph Hellwig <hch@infradead.org>, Jeff Moyer <jmoyer@redhat.com>,
        Shaohua Li <shli@fusionio.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: block: fix q->flush_rq NULL pointer crash on dm-mpath flush
Message-ID: <20140309032946.GA19029@redhat.com>
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On Sat, Mar 08 2014 at 10:18pm -0500,
Jens Axboe <axboe@kernel.dk> wrote:

> On 2014-03-08 17:57, Mike Snitzer wrote:
> >
> >I had a look at what you queued, thing is commit 1874198 replaced code
> >in blk_kick_flush() that did use list_add_tail().  So getting back to
> >the way the original code  was (before 1874198) would need something
> >like the following patch.
> >
> >But it isn't clear to me why we'd have the duality of front vs tail
> >additions for flushes.  Maybe Christoph knows?
> 
> Not sure it'd even make a difference with the use case, but always
> tail would be broken. But the flushing in general is a bit of a
> nightmare, so I'd be inclined to add your full fix too, at least
> this late in -rc.

OK, please feel free to add my Signed-off-by.