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s390/qdio: simplify math in get_*_buffer_frontier()

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When determining the buffer count that get_buf_states() should
be queried for, 'count' is capped at 127 buffers.
So the check
	q->first_to_check == (q->first_to_check + count) % 128
can be reduced to
	count == 0

This helps to emphasize that get_buf_states() is really only
called with count > 0.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Julian Wiedmann 2017-12-06 08:53:33 +01:00 committed by Martin Schwidefsky
parent bcbd41da3b
commit 152485bf76
1 changed files with 4 additions and 7 deletions
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11
drivers/s390/cio/qdio_main.c
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@ -502,8 +502,8 @@ static inline void inbound_primed(struct qdio_q *q, int count)
static int get_inbound_buffer_frontier(struct qdio_q *q)
{
int count, stop;
unsigned char state = 0;
int count;
q->timestamp = get_tod_clock_fast();
@ -512,9 +512,7 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
* would return 0.
*/
count = min(atomic_read(&q->nr_buf_used), QDIO_MAX_BUFFERS_MASK);
stop = add_buf(q->first_to_check, count);
if (q->first_to_check == stop)
if (!count)
goto out;
/*
@ -734,8 +732,8 @@ void qdio_inbound_processing(unsigned long data)
static int get_outbound_buffer_frontier(struct qdio_q *q)
{
int count, stop;
unsigned char state = 0;
int count;
q->timestamp = get_tod_clock_fast();
@ -751,8 +749,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)
* would return 0.
*/
count = min(atomic_read(&q->nr_buf_used), QDIO_MAX_BUFFERS_MASK);
stop = add_buf(q->first_to_check, count);
if (q->first_to_check == stop)
if (!count)
goto out;
count = get_buf_states(q, q->first_to_check, &state, count, 0, 1);