s390/qeth: don't take queue lock in send_packet_fast()

Locking the output queue prior to TX is needed on OSA devices,
to synchronize against a packing flush from the TX completion code
(via qeth_check_outbound_queue()).
But send_packet_fast() is only used for IQDs, which don't do packing.
So remove the locking, and apply some easy cleanups.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 17 deletions

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 77032801e30b..68e118f1202e 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -4040,35 +4040,23 @@ static int qeth_fill_buffer(struct qeth_qdio_out_q *queue,
 	return flush_cnt;
 }
 
-int qeth_do_send_packet_fast(struct qeth_card *card,
-			     struct qeth_qdio_out_q *queue, struct sk_buff *skb,
+int qeth_do_send_packet_fast(struct qeth_qdio_out_q *queue, struct sk_buff *skb,
 			     struct qeth_hdr *hdr, unsigned int offset,
 			     unsigned int hd_len)
 {
-	struct qeth_qdio_out_buffer *buffer;
-	int index;
+	int index = queue->next_buf_to_fill;
+	struct qeth_qdio_out_buffer *buffer = queue->bufs[index];
 
-	/* spin until we get the queue ... */
-	while (atomic_cmpxchg(&queue->state, QETH_OUT_Q_UNLOCKED,
-			      QETH_OUT_Q_LOCKED) != QETH_OUT_Q_UNLOCKED);
-	/* ... now we've got the queue */
-	index = queue->next_buf_to_fill;
-	buffer = queue->bufs[queue->next_buf_to_fill];
 	/*
 	 * check if buffer is empty to make sure that we do not 'overtake'
 	 * ourselves and try to fill a buffer that is already primed
 	 */
 	if (atomic_read(&buffer->state) != QETH_QDIO_BUF_EMPTY)
-		goto out;
-	queue->next_buf_to_fill = (queue->next_buf_to_fill + 1) %
-					  QDIO_MAX_BUFFERS_PER_Q;
-	atomic_set(&queue->state, QETH_OUT_Q_UNLOCKED);
+		return -EBUSY;
+	queue->next_buf_to_fill = (index + 1) % QDIO_MAX_BUFFERS_PER_Q;
 	qeth_fill_buffer(queue, buffer, skb, hdr, offset, hd_len);
 	qeth_flush_buffers(queue, index, 1);
 	return 0;
-out:
-	atomic_set(&queue->state, QETH_OUT_Q_UNLOCKED);
-	return -EBUSY;
 }
 EXPORT_SYMBOL_GPL(qeth_do_send_packet_fast);