netdev - [PATCH net-next 4/4] net: bridge: Refactor bridge port in locked mode to use jump labels

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Date:   Mon,  7 Feb 2022 11:07:42 +0100
From:   Hans Schultz <schultz.hans@...il.com>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     netdev@...r.kernel.org,
        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: [PATCH net-next 4/4] net: bridge: Refactor bridge port in locked mode to use jump labels

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+netdev@...il.com>
---
 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);
 
-- 
2.30.2