netdev - [PATCH net-next v1 1/1] net: openvswitch: remove unnecessary vlan init in key

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Date:   Tue,  7 Feb 2023 12:31:33 +0800
From:   Eddy Tao <taoyuan_eddy@...mail.com>
To:     netdev@...r.kernel.org
Cc:     Eddy Tao <taoyuan_eddy@...mail.com>,
        Pravin B Shelar <pshelar@....org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, dev@...nvswitch.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next v1 1/1] net: openvswitch: remove unnecessary vlan init in key_extract

Redefine clear_vlan to initialize one struct vlan_head
Define   clear_vlans to initialize key.eth.vlan and key.eth.cvlan
Calls the revised functions accurately

Reasoning:

For vlan packet, current code calls clear_vlan unnecessarily,
since parse_vlan sets key->eth.vlan and key->eth.cvlan correctly.
Only special case where return value <=0 needs inialization
certail key.eth.vlan or key.eth.cvlan specifically.

For none-vlan case, parse_vlan returns on the first parse_vlan_tag
which returns 0, in this case, calls clear_vlan

For MAC_PROTO_NONE, logic is intact after this revision

Signed-off-by: Eddy Tao <taoyuan_eddy@...mail.com>
---
 net/openvswitch/flow.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index e20d1a973417..30a90597cab6 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -480,12 +480,16 @@ static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh,
 	return 1;
 }
 
-static void clear_vlan(struct sw_flow_key *key)
+static inline void clear_vlan(struct vlan_head *vlan)
 {
-	key->eth.vlan.tci = 0;
-	key->eth.vlan.tpid = 0;
-	key->eth.cvlan.tci = 0;
-	key->eth.cvlan.tpid = 0;
+	vlan->tci = 0;
+	vlan->tpid = 0;
+}
+
+static inline void clear_vlans(struct sw_flow_key *key)
+{
+	clear_vlan(&key->eth.vlan);
+	clear_vlan(&key->eth.cvlan);
 }
 
 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
@@ -498,14 +502,18 @@ static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 	} else {
 		/* Parse outer vlan tag in the non-accelerated case. */
 		res = parse_vlan_tag(skb, &key->eth.vlan, true);
-		if (res <= 0)
+		if (res <= 0) {
+			clear_vlans(key);
 			return res;
+		}
 	}
 
 	/* Parse inner vlan tag. */
 	res = parse_vlan_tag(skb, &key->eth.cvlan, false);
-	if (res <= 0)
+	if (res <= 0) {
+		clear_vlan(&key->eth.cvlan);
 		return res;
+	}
 
 	return 0;
 }
@@ -918,8 +926,8 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
 	skb_reset_mac_header(skb);
 
 	/* Link layer. */
-	clear_vlan(key);
 	if (ovs_key_mac_proto(key) == MAC_PROTO_NONE) {
+		clear_vlans(key);
 		if (unlikely(eth_type_vlan(skb->protocol)))
 			return -EINVAL;
 
-- 
2.27.0