From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Subject: Re: [PATCH 2/4] if condition fix for __atapi_pio_bytes()
Date: Wed, 8 Jun 2005 11:48:45 +0200
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To: Albert Lee <albertcc@tw.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>, Linux IDE <linux-ide@vger.kernel.org>, Doug Maxey <dwm@maxeymade.com>

On 6/8/05, Albert Lee <albertcc@tw.ibm.com> wrote:
> Hi Bart:
> 
> >
> >
> > (bytes > qc->nbytes) condition can happen and this part of the patch
> > is fine with me
> > but I fail to see how (qc->cursg_ofs > sg->length) or (count > bytes)
> > can happen...
> >
> >       count = min(sg->length - qc->cursg_ofs, bytes);
> >
> >       /* don't cross page boundaries */
> >       count = min(count, (unsigned int)PAGE_SIZE - offset);
> >
> > Bartlomiej
> >
> >
> 
> Normally (qc->cursg_ofs > sg->length) or (count > bytes) won't happen.
> However, if we apply patch [4/4], which overrun the odd-length buffer by one byte,
> then (qc->cursg_ofs > sg->length) and (count > bytes) could happen.

If so wouldn't it be easier to round 'bytes' instead of 'count' in the patch #4?

* this patch (#2) gets simpler
* no need to round 'bytes' in the patch #3
* rounding can be moved from "sg loop" to the beginning of __atapi_pio_bytes()
  in the patch #4

[ unless I'm missing something ]

Thanks,
Bartlomiej