[PATCH 5.11 054/306] net: dsa: tag_mtk: fix 802.1ad VLAN egress

[gregkh]

From: Greg Kroah-Hartman <gre...@linuxfoundation.org>

From: DENG Qingfang <dqf...@gmail.com>

commit 9200f515c41f4cbaeffd8fdd1d8b6373a18b1b67 upstream.

A different TPID bit is used for 802.1ad VLAN frames.

Reported-by: Ilario Gelmetti <iocheson...@gmail.com>
Fixes: f0af34317f4b ("net: dsa: mediatek: combine MediaTek tag with VLAN tag")
Signed-off-by: DENG Qingfang <dqf...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/dsa/tag_mtk.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -13,6 +13,7 @@
 #define MTK_HDR_LEN            4
 #define MTK_HDR_XMIT_UNTAGGED          0
 #define MTK_HDR_XMIT_TAGGED_TPID_8100  1
+#define MTK_HDR_XMIT_TAGGED_TPID_88A8  2
 #define MTK_HDR_RECV_SOURCE_PORT_MASK  GENMASK(2, 0)
 #define MTK_HDR_XMIT_DP_BIT_MASK       GENMASK(5, 0)
 #define MTK_HDR_XMIT_SA_DIS            BIT(6)
@@ -21,8 +22,8 @@ static struct sk_buff *mtk_tag_xmit(stru
                                    struct net_device *dev)
 {
        struct dsa_port *dp = dsa_slave_to_port(dev);
+       u8 xmit_tpid;
        u8 *mtk_tag;
-       bool is_vlan_skb = true;
        unsigned char *dest = eth_hdr(skb)->h_dest;
        bool is_multicast_skb = is_multicast_ether_addr(dest) &&
                                !is_broadcast_ether_addr(dest);
@@ -33,10 +34,17 @@ static struct sk_buff *mtk_tag_xmit(stru
         * the both special and VLAN tag at the same time and then look up VLAN
         * table with VID.
         */
-       if (!skb_vlan_tagged(skb)) {
+       switch (skb->protocol) {
+       case htons(ETH_P_8021Q):
+               xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100;
+               break;
+       case htons(ETH_P_8021AD):
+               xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8;
+               break;
+       default:
+               xmit_tpid = MTK_HDR_XMIT_UNTAGGED;
                skb_push(skb, MTK_HDR_LEN);
                memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
-               is_vlan_skb = false;
        }
 
        mtk_tag = skb->data + 2 * ETH_ALEN;
@@ -44,8 +52,7 @@ static struct sk_buff *mtk_tag_xmit(stru
        /* Mark tag attribute on special tag insertion to notify hardware
         * whether that's a combined special tag with 802.1Q header.
         */
-       mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 :
-                    MTK_HDR_XMIT_UNTAGGED;
+       mtk_tag[0] = xmit_tpid;
        mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
 
        /* Disable SA learning for multicast frames */
@@ -53,7 +60,7 @@ static struct sk_buff *mtk_tag_xmit(stru
                mtk_tag[1] |= MTK_HDR_XMIT_SA_DIS;
 
        /* Tag control information is kept for 802.1Q */
-       if (!is_vlan_skb) {
+       if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) {
                mtk_tag[2] = 0;
                mtk_tag[3] = 0;
        }