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Sender: Tejun Heo <htejun@gmail.com>
Date: Tue, 7 Mar 2017 14:43:49 -0500
From: Tejun Heo <tj@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
	Lekshmi Pillai <lekshmicpillai@in.ibm.com>,
	NeilBrown <neilb@suse.de>, Omar Sandoval <osandov@osandov.com>
Subject: Re: [PATCH 02/11] block: Fix race of bdev open with gendisk shutdown
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Hello,

On Tue, Mar 07, 2017 at 12:14:20PM +0100, Jan Kara wrote:
> > Given that this isn't a super hot path, I think it'd be far better to
> > stick to a simpler synchronization mechanism.
> 
> I'd be happy to do so however struct gendisk does not have any lock in it
> and introducing a special lock just for that seems awkward.

I think even a awkward shared lock is better than memory barriers.
Barriers are the trickiest locking construct to get right and we
really shouldn't using that unless absolutely necessary.

Thanks.

-- 
tejun