[dm-devel] Re: [RFC PATCH 1/3] block: add rq->complete_io hook for request stacking
Jens Axboe
jens.axboe at oracle.com
Mon Mar 3 17:49:54 UTC 2008
On Mon, Mar 03 2008, Hannes Reinecke wrote:
> Hi Kiyoshi,
>
> Kiyoshi Ueda wrote:
> > This patch adds ->complete_io() hook for request stacking.
> > Request stacking drivers (such as request-based dm) can set
> > a callback for completion.
> > (The hook is not called in blk_end_io(), since request-based dm uses
> > it for clone completion in the following appendix patches.)
> >
> [ .. ]
> I would rather have rq->complete_io() to be pointing to blk_end_io in the
> default case, this way rq->complete_io() would always be valid and we
> would be saving us the if() clause.
The whole point of this ->complete_io() thread is that we cannot use the
above approach, before all drivers are converted from using
__blk_end_request() to blk_end_request(). And that requires some work.
--
Jens Axboe
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