s390/qeth: collect more TX statistics

Count the number of TX doorbells we issue to the qdio layer.

Also count the number of actual frames in a TX buffer, and then
use this data along with the byte count during TX completion.
We'll make additional use of the frame count in a subsequent patch.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core.h

@@ -402,6 +402,7 @@ struct qeth_qdio_out_buffer {
 	struct qdio_buffer *buffer;
 	atomic_t state;
 	int next_element_to_fill;
+	unsigned int frames;
 	unsigned int bytes;
 	struct sk_buff_head skb_list;
 	int is_header[QDIO_MAX_ELEMENTS_PER_BUFFER];
@@ -457,6 +458,7 @@ struct qeth_out_q_stats {
 	u64 tso_bytes;
 	u64 packing_mode_switch;
 	u64 stopped;
+	u64 doorbell;
 	u64 completion_yield;
 	u64 completion_timer;
 

drivers/s390/net/qeth_core_main.c

@@ -1155,17 +1155,20 @@ static void qeth_tx_complete_buf(struct qeth_qdio_out_buffer *buf, bool error,
 
 	QETH_TXQ_STAT_INC(queue, bufs);
 	QETH_TXQ_STAT_ADD(queue, buf_elements, buf->next_element_to_fill);
+	if (error) {
+		QETH_TXQ_STAT_ADD(queue, tx_errors, buf->frames);
+	} else {
+		QETH_TXQ_STAT_ADD(queue, tx_packets, buf->frames);
+		QETH_TXQ_STAT_ADD(queue, tx_bytes, buf->bytes);
+	}
+
 	while ((skb = __skb_dequeue(&buf->skb_list)) != NULL) {
 		unsigned int bytes = qdisc_pkt_len(skb);
 		bool is_tso = skb_is_gso(skb);
 		unsigned int packets;
 
 		packets = is_tso ? skb_shinfo(skb)->gso_segs : 1;
-		if (error) {
-			QETH_TXQ_STAT_ADD(queue, tx_errors, packets);
-		} else {
-			QETH_TXQ_STAT_ADD(queue, tx_packets, packets);
-			QETH_TXQ_STAT_ADD(queue, tx_bytes, bytes);
+		if (!error) {
 			if (skb->ip_summed == CHECKSUM_PARTIAL)
 				QETH_TXQ_STAT_ADD(queue, skbs_csum, packets);
 			if (skb_is_nonlinear(skb))
@@ -1202,6 +1205,7 @@ static void qeth_clear_output_buffer(struct qeth_qdio_out_q *queue,
 
 	qeth_scrub_qdio_buffer(buf->buffer, queue->max_elements);
 	buf->next_element_to_fill = 0;
+	buf->frames = 0;
 	buf->bytes = 0;
 	atomic_set(&buf->state, QETH_QDIO_BUF_EMPTY);
 }
@@ -3389,6 +3393,7 @@ static void qeth_flush_buffers(struct qeth_qdio_out_q *queue, int index,
 		}
 	}
 
+	QETH_TXQ_STAT_INC(queue, doorbell);
 	qdio_flags = QDIO_FLAG_SYNC_OUTPUT;
 	if (atomic_read(&queue->set_pci_flags_count))
 		qdio_flags |= QDIO_FLAG_PCI_OUT;
@@ -3942,6 +3947,7 @@ static int __qeth_xmit(struct qeth_card *card, struct qeth_qdio_out_q *queue,
 
 	next_element = qeth_fill_buffer(buffer, skb, hdr, offset, hd_len);
 	buffer->bytes += bytes;
+	buffer->frames += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
 	queue->prev_hdr = hdr;
 
 	flush = __netdev_tx_sent_queue(txq, bytes,
@@ -4032,6 +4038,8 @@ int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
 	}
 
 	next_element = qeth_fill_buffer(buffer, skb, hdr, offset, hd_len);
+	buffer->bytes += qdisc_pkt_len(skb);
+	buffer->frames += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
 
 	if (queue->do_pack)
 		QETH_TXQ_STAT_INC(queue, skbs_pack);
@@ -5668,7 +5676,7 @@ static int qeth_tx_poll(struct napi_struct *napi, int budget)
 			unsigned int bidx = QDIO_BUFNR(i);
 
 			buffer = queue->bufs[bidx];
-			packets += skb_queue_len(&buffer->skb_list);
+			packets += buffer->frames;
 			bytes += buffer->bytes;
 
 			qeth_handle_send_error(card, buffer, error);

drivers/s390/net/qeth_ethtool.c

@@ -39,6 +39,7 @@ static const struct qeth_stats txq_stats[] = {
 	QETH_TXQ_STAT("TSO bytes", tso_bytes),
 	QETH_TXQ_STAT("Packing mode switches", packing_mode_switch),
 	QETH_TXQ_STAT("Queue stopped", stopped),
+	QETH_TXQ_STAT("Doorbell", doorbell),
 	QETH_TXQ_STAT("Completion yield", completion_yield),
 	QETH_TXQ_STAT("Completion timer", completion_timer),
 };