FAILED: patch "[PATCH] net: dsa: tag_ocelot_8021q: fix inability to inject STP BPDUs" failed to apply to 5.14-stable tree

The patch below does not apply to the 5.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 43ba33b4f143965a451cfdc1e826b61f6933c887 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <[email protected]>
Date: Tue, 12 Oct 2021 14:40:43 +0300
Subject: [PATCH] net: dsa: tag_ocelot_8021q: fix inability to inject STP BPDUs
into BLOCKING ports

When setting up a bridge with stp_state 1, topology changes are not detected and loops are not blocked. This is because the standard way of transmitting a packet, based on VLAN IDs redirected by VCAP IS2 to the right egress port, does not override the port STP state (in the case of Ocelot switches, that's really the PGID_SRC masks).

To force a packet to be injected into a port that's BLOCKING, we must send it as a control packet, which means in the case of this tagger to send it using the manual register injection method. We already do this for PTP frames, extend the logic to apply to any link-local MAC DA.

index d05c352f96e5..3412051981d7 100644
@@ -42,8 +42,9 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 	u16 queue_mapping = skb_get_queue_mapping(skb);
 	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
+	struct ethhdr *hdr = eth_hdr(skb);
 
-	if (ocelot_ptp_rew_op(skb))
+	if (ocelot_ptp_rew_op(skb) || is_link_local_ether_addr(hdr->h_dest))
 		return ocelot_defer_xmit(dp, skb);
 
 	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,