[RFC PATCH 9/9] net: dsa: tag_sja1105: add compatibility with hwaccel VLAN tags

[Vladimir Oltean]

Check whether there is any hwaccel VLAN tag on RX, and if there is,
treat it as the tag_8021q header.

Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>
---
 net/dsa/tag_sja1105.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 9b4a4d719291..3710f9daa46d 100644
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -72,14 +72,21 @@ static inline bool sja1105_is_meta_frame(const struct 
sk_buff *skb)
 static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb)
 {
        struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+       u16 vlan_tci;
 
        if (hdr->h_vlan_proto == htons(ETH_P_SJA1105))
                return true;
 
-       if (hdr->h_vlan_proto != htons(ETH_P_8021Q))
+       if (hdr->h_vlan_proto != htons(ETH_P_8021Q) &&
+           !skb_vlan_tag_present(skb))
                return false;
 
-       return vid_is_dsa_8021q(ntohs(hdr->h_vlan_TCI) & VLAN_VID_MASK);
+       if (skb_vlan_tag_present(skb))
+               vlan_tci = skb_vlan_tag_get(skb);
+       else
+               vlan_tci = ntohs(hdr->h_vlan_TCI);
+
+       return vid_is_dsa_8021q(vlan_tci & VLAN_VID_MASK);
 }
 
 /* This is the first time the tagger sees the frame on RX.
@@ -283,7 +290,8 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 
        hdr = eth_hdr(skb);
        tpid = ntohs(hdr->h_proto);
-       is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q);
+       is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q ||
+                    skb_vlan_tag_present(skb));
        is_link_local = sja1105_is_link_local(skb);
        is_meta = sja1105_is_meta_frame(skb);
 
@@ -292,7 +300,12 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
        if (is_tagged) {
                /* Normal traffic path. */
                skb_push_rcsum(skb, ETH_HLEN);
-               __skb_vlan_pop(skb, &tci);
+               if (skb_vlan_tag_present(skb)) {
+                       tci = skb_vlan_tag_get(skb);
+                       __vlan_hwaccel_clear_tag(skb);
+               } else {
+                       __skb_vlan_pop(skb, &tci);
+               }
                skb_pull_rcsum(skb, ETH_HLEN);
                skb_reset_network_header(skb);
                skb_reset_transport_header(skb);
-- 
2.25.1