On Tuesday 04 December 2007, Kiyoshi Ueda wrote:
> Hi Bartlomiej,
>
> On Sat, 1 Dec 2007 23:53:05 +0100, Bartlomiej Zolnierkiewicz <[email protected]> wrote:
> > On Saturday 01 December 2007, Kiyoshi Ueda wrote:
> > > This patch converts "normal" parts of ide to use blk_end_request().
> > >
> > > Signed-off-by: Kiyoshi Ueda <[email protected]>
> > > Signed-off-by: Jun'ichi Nomura <[email protected]>
> > > ---
> > > drivers/ide/ide-cd.c | 6 +++---
> > > drivers/ide/ide-io.c | 17 ++++++-----------
> > > 2 files changed, 9 insertions(+), 14 deletions(-)
> >
> > [...]
> >
> > > Index: 2.6.24-rc3-mm2/drivers/ide/ide-io.c
> > > ===================================================================
> > > --- 2.6.24-rc3-mm2.orig/drivers/ide/ide-io.c
> > > +++ 2.6.24-rc3-mm2/drivers/ide/ide-io.c
> > > @@ -78,14 +78,9 @@ static int __ide_end_request(ide_drive_t
> > > ide_dma_on(drive);
> > > }
> > >
> > > - if (!end_that_request_chunk(rq, uptodate, nr_bytes)) {
> > > - add_disk_randomness(rq->rq_disk);
> > > - if (dequeue) {
> > > - if (!list_empty(&rq->queuelist))
> > > - blkdev_dequeue_request(rq);
> > > + if (!__blk_end_request(rq, uptodate, nr_bytes)) {
> > > + if (dequeue)
> > > HWGROUP(drive)->rq = NULL;
> > > - }
> > > - end_that_request_last(rq, uptodate);
> > > ret = 0;
> > > }
> >
> > 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 <[email protected]>
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