qlcnic: additional driver statistics

Added additional driver statistics to track errors in rcv/tx path.

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/qlcnic/qlcnic_init.c b/drivers/net/qlcnic/qlcnic_init.c
index 01ce74e..9ef9f58 100644
--- a/drivers/net/qlcnic/qlcnic_init.c
+++ b/drivers/net/qlcnic/qlcnic_init.c
@@ -1287,6 +1287,7 @@
 			rds_ring->dma_size, PCI_DMA_FROMDEVICE);
 
 	if (pci_dma_mapping_error(pdev, dma)) {
+		adapter->stats.rx_dma_map_error++;
 		dev_kfree_skb_any(skb);
 		buffer->skb = NULL;
 		return -ENOMEM;
@@ -1311,8 +1312,10 @@
 			PCI_DMA_FROMDEVICE);
 
 	skb = buffer->skb;
-	if (!skb)
+	if (!skb) {
+		adapter->stats.null_skb++;
 		goto no_skb;
+	}
 
 	if (likely(adapter->rx_csum && cksum == STATUS_CKSUM_OK)) {
 		adapter->stats.csummed++;
@@ -1502,6 +1505,8 @@
 
 		if (rxbuf)
 			list_add_tail(&rxbuf->list, &sds_ring->free_list[ring]);
+		else
+			adapter->stats.null_rxbuf++;
 
 skip:
 		for (; desc_cnt > 0; desc_cnt--) {