[net-next,2/4] s390/qeth: fix packing buffer statistics

Submitted by Julian Wiedmann on June 19, 2017, 11:22 a.m.

Details

Message ID 20170619112225.30471-3-jwi@linux.vnet.ibm.com
State Changes Requested
Delegated to: David Miller
Headers show

Commit Message

Julian Wiedmann June 19, 2017, 11:22 a.m.
There's two spots in qeth_send_packet() where we don't accurately
account for transmitted packing buffers in qeth's performance
statistics:

1) when flushing the current buffer due to insufficient size,
   and the next buffer is not EMPTY, we need to account for that
   flushed buffer.
2) when synchronizing with the TX completion code, we reset
   flush_count and thus forget to account for any previously
   flushed buffers.

Reported-by: Nils Hoppmann <niho@de.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
---
 drivers/s390/net/qeth_core_main.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

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diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 08338f27c82c..13a55f1dee7a 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -4103,7 +4103,8 @@  int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
 							   flush_count);
 				atomic_set(&queue->state,
 						QETH_OUT_Q_UNLOCKED);
-				return -EBUSY;
+				rc = -EBUSY;
+				goto out;
 			}
 		}
 	}
@@ -4122,19 +4123,21 @@  int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
 	 * In that case we will enter this loop
 	 */
 	while (atomic_dec_return(&queue->state)) {
-		flush_count = 0;
 		start_index = queue->next_buf_to_fill;
 		/* check if we can go back to non-packing state */
-		flush_count += qeth_switch_to_nonpacking_if_needed(queue);
+		tmp = qeth_switch_to_nonpacking_if_needed(queue);
 		/*
 		 * check if we need to flush a packing buffer to get a pci
 		 * flag out on the queue
 		 */
-		if (!flush_count && !atomic_read(&queue->set_pci_flags_count))
-			flush_count += qeth_prep_flush_pack_buffer(queue);
-		if (flush_count)
-			qeth_flush_buffers(queue, start_index, flush_count);
+		if (!tmp && !atomic_read(&queue->set_pci_flags_count))
+			tmp = qeth_prep_flush_pack_buffer(queue);
+		if (tmp) {
+			qeth_flush_buffers(queue, start_index, tmp);
+			flush_count += tmp;
+		}
 	}
+out:
 	/* at this point the queue is UNLOCKED again */
 	if (queue->card->options.performance_stats && do_pack)
 		queue->card->perf_stats.bufs_sent_pack += flush_count;