This is a note to let you know that I've just added the patch titled net: dsa: tag_gswip: let DSA core deal with TX reallocation to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-dsa-tag_gswip-let-dsa-core-deal-with-tx-realloca.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f5e9219ce4606a568cf76d4650aed661d642288a Author: Vladimir Oltean <vladimir.oltean@xxxxxxx> Date: Sun Nov 1 21:16:19 2020 +0200 net: dsa: tag_gswip: let DSA core deal with TX reallocation [ Upstream commit 9b9826ae117f211bcbdc75db844d5fd8b159fc59 ] Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. This one is interesting, the DSA tag is 8 bytes on RX and 4 bytes on TX. Because DSA is unaware of asymmetrical tag lengths, the overhead/needed headroom is declared as 8 bytes and therefore 4 bytes larger than it needs to be. If this becomes a problem, and the GSWIP driver can't be converted to a uniform header length, we might need to make DSA aware of separate RX/TX overhead values. Cc: Hauke Mehrtens <hauke@xxxxxxxxxx> Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/dsa/tag_gswip.c b/net/dsa/tag_gswip.c index 408d4af390a0..2f5bd5e338ab 100644 --- a/net/dsa/tag_gswip.c +++ b/net/dsa/tag_gswip.c @@ -60,13 +60,8 @@ static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - int err; u8 *gswip_tag; - err = skb_cow_head(skb, GSWIP_TX_HEADER_LEN); - if (err) - return NULL; - skb_push(skb, GSWIP_TX_HEADER_LEN); gswip_tag = skb->data;