net: sparx5: Fix return type of sparx5_port_xmit_impl

The ndo_start_xmit field in net_device_ops is expected to be of type
netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev).

The mismatched return type breaks forward edge kCFI since the underlying
function definition does not match the function hook definition.

The return type of sparx5_port_xmit_impl should be changed from int to
netdev_tx_t.
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1703
Cc: llvm@lists.linux.dev
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/sparx5/sparx5_main.h

@@ -291,7 +291,7 @@ struct frame_info {
 void sparx5_xtr_flush(struct sparx5 *sparx5, u8 grp);
 void sparx5_ifh_parse(u32 *ifh, struct frame_info *info);
 irqreturn_t sparx5_xtr_handler(int irq, void *_priv);
-int sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev);
+netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev);
 int sparx5_manual_injection_mode(struct sparx5 *sparx5);
 void sparx5_port_inj_timer_setup(struct sparx5_port *port);
 

drivers/net/ethernet/microchip/sparx5/sparx5_packet.c

@@ -222,13 +222,13 @@ static int sparx5_inject(struct sparx5 *sparx5,
 	return NETDEV_TX_OK;
 }
 
-int sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev)
+netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev)
 {
 	struct net_device_stats *stats = &dev->stats;
 	struct sparx5_port *port = netdev_priv(dev);
 	struct sparx5 *sparx5 = port->sparx5;
 	u32 ifh[IFH_LEN];
-	int ret;
+	netdev_tx_t ret;
 
 	memset(ifh, 0, IFH_LEN * 4);
 	sparx5_set_port_ifh(ifh, port->portno);