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Message-Id: <20071204.130441.41629552.k-ueda@ct.jp.nec.com>
Date: Tue, 04 Dec 2007 13:04:41 -0500 (EST)
From: Kiyoshi Ueda <k-ueda@...jp.nec.com>
To: bzolnier@...il.com
Cc: jens.axboe@...cle.com, bharrosh@...asas.com,
linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
linux-ide@...r.kernel.org, dm-devel@...hat.com,
j-nomura@...jp.nec.com
Subject: Re: [PATCH 24/28] blk_end_request: changing ide normal caller
(take 3)
Hi Bartlomiej,
On Tue, 4 Dec 2007 14:47:00 +0100, Bartlomiej Zolnierkiewicz wrote:
> > > Hmmm, this seems to change the old behavior (the request should
> > > be dequeued from the queue only if 'dequeue' variable is set)
> > > and AFAIR some error handling code (in ide-cd?) depends on the
> > > old behavior so please revisit this patch.
> >
> > blk_end_request() takes care of the dequeue like below,
> > so I think no problem. (Please see PATCH 01)
> >
> > > + /* rq->queuelist of dequeued request should be list_empty() */
> > > + if (!list_empty(&rq->queuelist))
> > > + blkdev_dequeue_request(rq);
> >
> > In the case of ide-cd,
> > o 'dequeue' variable is 1 only when the request is still linked
> > to the queue (i.e. rq->queuelist is not empty)
> > o 'dequeue' variable is 0 only when the request has already been
> > removed from the queue (i.e. rq->queuelist is empty)
> > So blk_end_request() can handle it correctly.
>
> It would be helpful to add the above explanation to a patch description.
>
> > If there are any drivers which don't want dequeue the queued request,
> > the code above would not work.
> > But, as far as I investigated, I have never seen such a requirement
> > in device drivers.
> >
> > Do you think that ide may still gets a problem for the 'dequeue'?
>
> Everything seems to be fine now.
>
> Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
Thank you for the check.
OK, I'll add the explanation about the 'dequeue' to patch description.
Thanks,
Kiyoshi Ueda
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