net: hsr: Disable promiscuous mode in offload mode

When port-to-port forwarding for interfaces in HSR node is enabled,
disable promiscuous mode since L2 frame forward happens at the
offloaded hardware.

Signed-off-by: Ravi Gunasekaran <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/hsr/hsr_device.c

···
 	if (res)
 		goto err_add_master;
 
+	/* HSR forwarding offload supported in lower device? */
+	if ((slave[0]->features & NETIF_F_HW_HSR_FWD) &&
+	    (slave[1]->features & NETIF_F_HW_HSR_FWD))
+		hsr->fwd_offloaded = true;
+
 	res = register_netdevice(hsr_dev);
 	if (res)
 		goto err_unregister;

net/hsr/hsr_main.h

···
 	u8 net_id;		/* for PRP, it occupies most significant 3 bits
 				 * of lan_id
 				 */
+	bool fwd_offloaded;	/* Forwarding offloaded to HW */
 	unsigned char		sup_multicast_addr[ETH_ALEN] __aligned(sizeof(u16));
 				/* Align to u16 boundary to avoid unaligned access
 				 * in ether_addr_equal

net/hsr/hsr_slave.c

···
 	struct hsr_port *master;
 	int res;
 
-	res = dev_set_promiscuity(dev, 1);
-	if (res)
-		return res;
+	/* Don't use promiscuous mode for offload since L2 frame forward
+	 * happens at the offloaded hardware.
+	 */
+	if (!port->hsr->fwd_offloaded) {
+		res = dev_set_promiscuity(dev, 1);
+		if (res)
+			return res;
+	}
 
 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
 	hsr_dev = master->dev;
···
 fail_rx_handler:
 	netdev_upper_dev_unlink(dev, hsr_dev);
 fail_upper_dev_link:
-	dev_set_promiscuity(dev, -1);
+	if (!port->hsr->fwd_offloaded)
+		dev_set_promiscuity(dev, -1);
+
 	return res;
 }