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Date: Tue, 28 Apr 2015 14:12:34 +0200
From: Christoph Hellwig <hch@lst.de>
To: Ming Lin <mlin@kernel.org>
Cc: linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        Jens Axboe <axboe@kernel.dk>,
        Kent Overstreet <kent.overstreet@gmail.com>,
        Dongsu Park <dongsu.park@profitbricks.com>,
        Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 02/10] block: simplify bio_add_page()
Message-ID: <20150428121234.GA10479@lst.de>
References: <1430203717-13307-1-git-send-email-mlin@kernel.org> <1430203717-13307-3-git-send-email-mlin@kernel.org>
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On Mon, Apr 27, 2015 at 11:48:29PM -0700, Ming Lin wrote:
> Note that removing call to ->merge_bvec_fn() is fine for
> bio_add_pc_page(), as SCSI devices usually don't even need that.
> Few exceptional cases like pscsi or osd are not affected either.

This explanation confuses me.  Based on my reading of the code I'd
replace it with something like:

Removing the call to ->merge_bvec_fn() is also fine, as no driver that
implements support for BLOCK_PC commands even has a ->merge_bvec_fn()
method.