net: dsa: tag_qca: return early if dev is not found

Currently checksum is recalculated and dsa tag stripped even if we later
don't find the dev.

To improve code, exit early if we don't find the dev and skip additional
operation on the skb since it will be freed anyway.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230730074113.21889-1-ansuelsmth@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index e757c8de06f16ef0f552db2336d34a8c85065936..e5ff7c34e577cada32e6ea56330ddf2976ac6ea2 100644 (file)
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -75,10 +75,6 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
                return NULL;
        }
 
-       /* Remove QCA tag and recalculate checksum */
-       skb_pull_rcsum(skb, QCA_HDR_LEN);
-       dsa_strip_etype_header(skb, QCA_HDR_LEN);
-
        /* Get source port information */
        port = FIELD_GET(QCA_HDR_RECV_SOURCE_PORT, hdr);
 
@@ -86,6 +82,10 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
        if (!skb->dev)
                return NULL;
 
+       /* Remove QCA tag and recalculate checksum */
+       skb_pull_rcsum(skb, QCA_HDR_LEN);
+       dsa_strip_etype_header(skb, QCA_HDR_LEN);
+
        return skb;
 }