Re: [PATCH 1/1] drivers/s390/cio/qdio_main.c: replace shift loop by ilog2

From: Joe Perches
Date: Tue May 20 2014 - 12:45:53 EST


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?

count may be better unsigned.

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