qede: Fix system crash on configuring channels.

Under heavy traffic load, when changing number of channels via
ethtool (ethtool -L) which will cause interface to be reloaded,
it was observed that some packets gets transmitted on old TX
channel/queue id which doesn't really exist after the channel
configuration leads to system crash.

Add a safeguard in the driver by validating queue id through
ndo_select_queue() which is called before the ndo_start_xmit().
Signed-off-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qede/qede.h

@@ -494,6 +494,9 @@ struct qede_reload_args {
 
 /* Datapath functions definition */
 netdev_tx_t qede_start_xmit(struct sk_buff *skb, struct net_device *ndev);
+u16 qede_select_queue(struct net_device *dev, struct sk_buff *skb,
+		      struct net_device *sb_dev,
+		      select_queue_fallback_t fallback);
 netdev_features_t qede_features_check(struct sk_buff *skb,
 				      struct net_device *dev,
 				      netdev_features_t features);

drivers/net/ethernet/qlogic/qede/qede_fp.c

@@ -1695,6 +1695,19 @@ netdev_tx_t qede_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	return NETDEV_TX_OK;
 }
 
+u16 qede_select_queue(struct net_device *dev, struct sk_buff *skb,
+		      struct net_device *sb_dev,
+		      select_queue_fallback_t fallback)
+{
+	struct qede_dev *edev = netdev_priv(dev);
+	int total_txq;
+
+	total_txq = QEDE_TSS_COUNT(edev) * edev->dev_info.num_tc;
+
+	return QEDE_TSS_COUNT(edev) ?
+		fallback(dev, skb, NULL) % total_txq :  0;
+}
+
 /* 8B udp header + 8B base tunnel header + 32B option length */
 #define QEDE_MAX_TUN_HDR_LEN 48
 

drivers/net/ethernet/qlogic/qede/qede_main.c

@@ -631,6 +631,7 @@ static const struct net_device_ops qede_netdev_ops = {
 	.ndo_open = qede_open,
 	.ndo_stop = qede_close,
 	.ndo_start_xmit = qede_start_xmit,
+	.ndo_select_queue = qede_select_queue,
 	.ndo_set_rx_mode = qede_set_rx_mode,
 	.ndo_set_mac_address = qede_set_mac_addr,
 	.ndo_validate_addr = eth_validate_addr,
@@ -666,6 +667,7 @@ static const struct net_device_ops qede_netdev_vf_ops = {
 	.ndo_open = qede_open,
 	.ndo_stop = qede_close,
 	.ndo_start_xmit = qede_start_xmit,
+	.ndo_select_queue = qede_select_queue,
 	.ndo_set_rx_mode = qede_set_rx_mode,
 	.ndo_set_mac_address = qede_set_mac_addr,
 	.ndo_validate_addr = eth_validate_addr,
@@ -684,6 +686,7 @@ static const struct net_device_ops qede_netdev_vf_xdp_ops = {
 	.ndo_open = qede_open,
 	.ndo_stop = qede_close,
 	.ndo_start_xmit = qede_start_xmit,
+	.ndo_select_queue = qede_select_queue,
 	.ndo_set_rx_mode = qede_set_rx_mode,
 	.ndo_set_mac_address = qede_set_mac_addr,
 	.ndo_validate_addr = eth_validate_addr,