net/mlx4_en: Split SW RX dropped counter per RX ring

Count SW packet drops per RX ring instead of a global counter. This
will allow monitoring the number of rx drops per ring.

In addition, SW rx_dropped counter was overwritten by HW rx_dropped
counter, sum both of them instead to show the accurate value.

Fixes: a3333b35da16 ('net/mlx4_en: Moderate ethtool callback to [...] ')
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reported-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
index f69584a..c761194 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
@@ -337,7 +337,7 @@
 	case ETH_SS_STATS:
 		return bitmap_iterator_count(&it) +
 			(priv->tx_ring_num * 2) +
-			(priv->rx_ring_num * 2);
+			(priv->rx_ring_num * 3);
 	case ETH_SS_TEST:
 		return MLX4_EN_NUM_SELF_TEST - !(priv->mdev->dev->caps.flags
 					& MLX4_DEV_CAP_FLAG_UC_LOOPBACK) * 2;
@@ -404,6 +404,7 @@
 	for (i = 0; i < priv->rx_ring_num; i++) {
 		data[index++] = priv->rx_ring[i]->packets;
 		data[index++] = priv->rx_ring[i]->bytes;
+		data[index++] = priv->rx_ring[i]->dropped;
 	}
 	spin_unlock_bh(&priv->stats_lock);
 
@@ -477,6 +478,8 @@
 				"rx%d_packets", i);
 			sprintf(data + (index++) * ETH_GSTRING_LEN,
 				"rx%d_bytes", i);
+			sprintf(data + (index++) * ETH_GSTRING_LEN,
+				"rx%d_dropped", i);
 		}
 		break;
 	case ETH_SS_PRIV_FLAGS: