[RFC 9/9] net: dsa: fix EDSA frame from hwaccel frame

[Vivien Didelot <vivien.didelot@savoirfairelinux.com>]

If the underlying network device features NETIF_F_HW_VLAN_CTAG_TX,
an EDSA frame is prepended with a 802.1q header once queued.

To fix this, push the VLAN tag to the payload if present, before
checking the frame protocol.

[note: we may prefer to access directly VLAN TCI from hwaccel frames,
but this approach is simpler.]

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
---
 net/dsa/tag_edsa.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
index 9aeda59..c1c9548 100644
--- a/net/dsa/tag_edsa.c
+++ b/net/dsa/tag_edsa.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include "dsa_priv.h"
@@ -24,6 +25,10 @@ static netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev)
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;
 
+	skb = vlan_hwaccel_push_inside(skb);
+	if (unlikely(!skb))
+		return -ENOMEM;
+
 	/*
 	 * Convert the outermost 802.1q tag to a DSA tag and prepend
 	 * a DSA ethertype field is the packet is tagged, or insert
-- 
2.4.1