yes, the callers guarantee that count > 0 here.
Regards, Ursula Braun
On Thu, 2014-05-22 at 12:14 +0200, Ursula Braun1 wrote:
> From: Sebastian Ott <seb...@linux.vnet.ibm.com>
> To: Joe Perches <j...@perches.com>, Ursula
> Braun1/Germany/IBM@IBMDE,
> Cc: Fabian Frederick <f...@skynet.be>, linux-kernel
> <linux-kernel@vger.kernel.org>, akpm <a...@linux-foundation.org>
> Date: 21/05/2014 14:32
> Subject: Re: [PATCH 1/1] drivers/s390/cio/qdio_main.c: replace
> shift loop by ilog2
>
> ______________________________________________________________________
>
>
>
> On Tue, 20 May 2014, Joe Perches wrote:
> > On Tue, 2014-05-20 at 18:37 +0200, Fabian Frederick wrote:
> > > This is untested.
> > []
> > > diff --git a/drivers/s390/cio/qdio_main.c
> b/drivers/s390/cio/qdio_main.c
> > []
> > > @@ -411,15 +411,14 @@ static inline void qdio_stop_polling(struct
> qdio_q *q)
> > >
> > > static inline void account_sbals(struct qdio_q *q, int count)
> > > {
> > > - int pos = 0;
> > > + int pos;
> > >
> > > q->q_stats.nr_sbal_total += count;
> > > if (count == QDIO_MAX_BUFFERS_MASK) {
> > > q->q_stats.nr_sbals[7]++;
> > > return;
> > > }
> > > - while (count >>= 1)
> > > - pos++;
> > > + pos = ilog2(count);
> >
> > What guarantees count > 0 here?
>
> We would already be screwed when called with count < 0. Ursula, do the
> callers assure that count is positive?
>
> Regards,
> Sebastian
> >
> > count may be better unsigned.
> >
> >
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