linux-kernel - Re: [PATCH net-next v2 5/5] net: bridge: Refactor bridge port in locked mode to use jump labels

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Date:   Thu, 10 Feb 2022 10:31:43 +0200
From:   Nikolay Aleksandrov <razor@...ckwall.org>
To:     Hans Schultz <schultz.hans@...il.com>, davem@...emloft.net,
        kuba@...nel.org
Cc:     netdev@...r.kernel.org, Hans Schultz <schultz.hans+lkml@...il.com>,
        Hans Schultz <schultz.hans+netdev@...il.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        bridge@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2 5/5] net: bridge: Refactor bridge port in
 locked mode to use jump labels

On 09/02/2022 15:05, Hans Schultz wrote:
> From: Hans Schultz <schultz.hans+lkml@...il.com>
> 
> As the locked mode feature is in the hot path of the bridge modules
> reception of packets, it needs to be refactored to use jump labels
> for optimization.
> 
> Signed-off-by: Hans Schultz <schultz.hans+lkml@...il.com>
> Signed-off-by: Hans Schultz <schultz.hans+netdev@...il.com>
> ---

Why two (almost) identical sign-offs?

Also, as Ido mentioned, please fold this patch into patch 01.

>  net/bridge/br_input.c   | 22 ++++++++++++++++++----
>  net/bridge/br_netlink.c |  6 ++++++
>  net/bridge/br_private.h |  2 ++
>  3 files changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 469e3adbce07..6fc428d6bac5 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -23,6 +23,18 @@
>  #include "br_private.h"
>  #include "br_private_tunnel.h"
>  
> +static struct static_key_false br_input_locked_port_feature;
> +
> +void br_input_locked_port_add(void)
> +{
> +	static_branch_inc(&br_input_locked_port_feature);
> +}
> +
> +void br_input_locked_port_remove(void)
> +{
> +	static_branch_dec(&br_input_locked_port_feature);
> +}
> +
>  static int
>  br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
>  {
> @@ -91,10 +103,12 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
>  				&state, &vlan))
>  		goto out;
>  
> -	if (p->flags & BR_PORT_LOCKED) {
> -		fdb_entry = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
> -		if (!(fdb_entry && fdb_entry->dst == p))
> -			goto drop;
> +	if (static_branch_unlikely(&br_input_locked_port_feature)) {
> +		if (p->flags & BR_PORT_LOCKED) {
> +			fdb_entry = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
> +			if (!(fdb_entry && fdb_entry->dst == p))
> +				goto drop;
> +		}
>  	}
>  
>  	nbp_switchdev_frame_mark(p, skb);
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 7d4432ca9a20..e3dbe9fed75c 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -860,6 +860,7 @@ static int br_set_port_state(struct net_bridge_port *p, u8 state)
>  static void br_set_port_flag(struct net_bridge_port *p, struct nlattr *tb[],
>  			     int attrtype, unsigned long mask)
>  {
> +	bool locked = p->flags & BR_PORT_LOCKED;
>  	if (!tb[attrtype])
>  		return;
>  
> @@ -867,6 +868,11 @@ static void br_set_port_flag(struct net_bridge_port *p, struct nlattr *tb[],
>  		p->flags |= mask;
>  	else
>  		p->flags &= ~mask;
> +
> +	if ((p->flags & BR_PORT_LOCKED) && !locked)
> +		br_input_locked_port_add();
> +	if (!(p->flags & BR_PORT_LOCKED) && locked)
> +		br_input_locked_port_remove();
>  }
>  
>  /* Process bridge protocol info on port */
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 2661dda1a92b..0ec3ef897978 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -832,6 +832,8 @@ void br_manage_promisc(struct net_bridge *br);
>  int nbp_backup_change(struct net_bridge_port *p, struct net_device *backup_dev);
>  
>  /* br_input.c */
> +void br_input_locked_port_add(void);
> +void br_input_locked_port_remove(void);
>  int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb);
>  rx_handler_func_t *br_get_rx_handler(const struct net_device *dev);
>