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authorJulian Wiedmann <jwi@linux.vnet.ibm.com>2017-12-06 08:53:33 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-03-26 16:12:25 +0200
commit152485bf76907ac7a2cc0a63b0822b23ef25da56 (patch)
treee4ea6117a3466c3b0dd253be6a9b6d8796ab9a67 /drivers/s390/cio/qdio_main.c
parentMerge tag 'vfio-ccw-20180305' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw into features (diff)
downloadlinux-dev-152485bf76907ac7a2cc0a63b0822b23ef25da56.tar.xz
linux-dev-152485bf76907ac7a2cc0a63b0822b23ef25da56.zip
s390/qdio: simplify math in get_*_buffer_frontier()
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>
Diffstat (limited to '')
-rw-r--r--drivers/s390/cio/qdio_main.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index d5b02de02a3a..6b340e6e29ac 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -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);