net: dsa: tag_qca: Make sure there is headroom for tag

[ Upstream commit 04fb91243a853dbde216d829c79d9632e52aa8d9 ]

Passing tag size to skb_cow_head will make sure
there is enough headroom for the tag data.
This change does not introduce any overhead in case there
is already available headroom for tag.

Signed-off-by: Per Forlin <perfn@axis.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index 66a9521..9c0dd31 100644 (file)
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -41,7 +41,7 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
        struct dsa_port *dp = dsa_slave_to_port(dev);
        u16 *phdr, hdr;
 
-       if (skb_cow_head(skb, 0) < 0)
+       if (skb_cow_head(skb, QCA_HDR_LEN) < 0)
                return NULL;
 
        skb_push(skb, QCA_HDR_LEN);