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Date: Mon, 27 Mar 2017 10:14:21 -0700
From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neilb@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>,
        Ming Lei <tom.leiming@gmail.com>, Jens Axboe <axboe@kernel.dk>,
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        Mike Snitzer <snitzer@redhat.com>, Shaohua Li <shli@kernel.org>,
        linux-kernel@vger.kernel.org,
        "Martin K . Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH v3] block: trace completion of all bios.
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On Mon, Mar 27, 2017 at 08:49:57PM +1100, NeilBrown wrote:
> On Mon, Mar 27 2017, Christoph Hellwig wrote:
> 
> > I don't really like the flag at all.  I'd much prefer a __bio_endio
> > with a 'bool trace' flag.  Also please remove the manual tracing in
> > dm.ċ.  Once that is done I suspect we can also remove the
> > block_bio_complete export.
> 
> Can you say why you don't like it?

It uses up a precious bit in the bio for something that should be state
that can be determined in the caller at compile time.