s390/qeth: fix packing buffer statistics

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

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;