Re: [RFC net-next v3 09/10] net: bridge: mrp: Integrate MRP into the bridge

From: Andrew Lunn <andrew@lunn.ch>
To: Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	bridge@lists.linux-foundation.org, jiri@resnulli.us,
	ivecera@redhat.com, davem@davemloft.net,
	roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com,
	anirudh.venkataramanan@intel.com, olteanv@gmail.com,
	jeffrey.t.kirsher@intel.com, UNGLinuxDriver@microchip.com
Subject: Re: [RFC net-next v3 09/10] net: bridge: mrp: Integrate MRP into the bridge
Date: Sat, 25 Jan 2020 17:16:15 +0100	[thread overview]
Message-ID: <20200125161615.GD18311@lunn.ch> (raw)
In-Reply-To: <20200124161828.12206-10-horatiu.vultur@microchip.com>

>  br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
> @@ -338,6 +341,17 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
>  			return RX_HANDLER_CONSUMED;
>  		}
>  	}
> +#ifdef CONFIG_BRIDGE_MRP
> +	/* If there is no MRP instance do normal forwarding */
> +	if (!p->mrp_aware)
> +		goto forward;
> +
> +	if (skb->protocol == htons(ETH_P_MRP))
> +		return RX_HANDLER_PASS;

What MAC address is used for these MRP frames? It would make sense to
use a L2 link local destination address, since i assume they are not
supposed to be forwarded by the bridge. If so, you could extend the
if (unlikely(is_link_local_ether_addr(dest))) condition.

> +
> +	if (p->state == BR_STATE_BLOCKING)
> +		goto drop;
> +#endif

Is this needed? The next block of code is a switch statement on
p->state. The default case, which BR_STATE_BLOCKING should hit, is
drop.

This function is on the hot path. So we should try to optimize it as
much as possible.

     Andrew