Merge branch 'net-hsr-use-the-seqnr-lock-for-frames-received-via-interlink-port'

Sebastian Andrzej Siewior says:

====================
net: hsr: Use the seqnr lock for frames received via interlink port.

This is follow-up to the thread at
https://lore.kernel.org/all/20240904133725.1073963-1-edumazet@google.com/
====================

Link: https://patch.msgid.link/20240906132816.657485-1-bigeasy@linutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/hsr/hsr_device.c

@@ -625,7 +625,6 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 	/* Overflow soon to find bugs easier: */
 	hsr->sequence_nr = HSR_SEQNR_START;
 	hsr->sup_sequence_nr = HSR_SUP_SEQNR_START;
-	hsr->interlink_sequence_nr = HSR_SEQNR_START;
 
 	timer_setup(&hsr->announce_timer, hsr_announce, 0);
 	timer_setup(&hsr->prune_timer, hsr_prune_nodes, 0);

net/hsr/hsr_main.h

@@ -203,7 +203,6 @@ struct hsr_priv {
 	struct timer_list	prune_proxy_timer;
 	int announce_count;
 	u16 sequence_nr;
-	u16 interlink_sequence_nr; /* Interlink port seq_nr */
 	u16 sup_sequence_nr;	/* For HSRv1 separate seq_nr for supervision */
 	enum hsr_version prot_version;	/* Indicate if HSRv0, HSRv1 or PRPv1 */
 	spinlock_t seqnr_lock;	/* locking for sequence_nr */

net/hsr/hsr_slave.c

@@ -67,7 +67,16 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
 		skb_set_network_header(skb, ETH_HLEN + HSR_HLEN);
 	skb_reset_mac_len(skb);
 
-	hsr_forward_skb(skb, port);
+	/* Only the frames received over the interlink port will assign a
+	 * sequence number and require synchronisation vs other sender.
+	 */
+	if (port->type == HSR_PT_INTERLINK) {
+		spin_lock_bh(&hsr->seqnr_lock);
+		hsr_forward_skb(skb, port);
+		spin_unlock_bh(&hsr->seqnr_lock);
+	} else {
+		hsr_forward_skb(skb, port);
+	}
 
 finish_consume:
 	return RX_HANDLER_CONSUMED;