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From:   Mans Rullgard <mans@mansr.com>
To:     Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Juergen Borleis <jbe@pengutronix.de>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2] net: dsa: lan9303: handle hwaccel VLAN tags
Date:   Wed, 16 Feb 2022 12:46:34 +0000
Message-Id: <20220216124634.23123-1-mans@mansr.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Check for a hwaccel VLAN tag on rx and use it if present.  Otherwise,
use __skb_vlan_pop() like the other tag parsers do.  This fixes the case
where the VLAN tag has already been consumed by the master.

Signed-off-by: Mans Rullgard <mans@mansr.com>
---
Changes:
- call skb_push/pull only where actually needed
---
 net/dsa/tag_lan9303.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c
index cb548188f813..98d7d7120bab 100644
--- a/net/dsa/tag_lan9303.c
+++ b/net/dsa/tag_lan9303.c
@@ -77,7 +77,6 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
 
 static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
 {
-	__be16 *lan9303_tag;
 	u16 lan9303_tag1;
 	unsigned int source_port;
 
@@ -87,14 +86,15 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
 		return NULL;
 	}
 
-	lan9303_tag = dsa_etype_header_pos_rx(skb);
-
-	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
-		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
-		return NULL;
+	if (skb_vlan_tag_present(skb)) {
+		lan9303_tag1 = skb_vlan_tag_get(skb);
+		__vlan_hwaccel_clear_tag(skb);
+	} else {
+		skb_push_rcsum(skb, ETH_HLEN);
+		__skb_vlan_pop(skb, &lan9303_tag1);
+		skb_pull_rcsum(skb, ETH_HLEN);
 	}
 
-	lan9303_tag1 = ntohs(lan9303_tag[1]);
 	source_port = lan9303_tag1 & 0x3;
 
 	skb->dev = dsa_master_find_slave(dev, 0, source_port);
@@ -103,13 +103,6 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
 		return NULL;
 	}
 
-	/* remove the special VLAN tag between the MAC addresses
-	 * and the current ethertype field.
-	 */
-	skb_pull_rcsum(skb, 2 + 2);
-
-	dsa_strip_etype_header(skb, LAN9303_TAG_LEN);
-
 	if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU))
 		dsa_default_offload_fwd_mark(skb);
 
-- 
2.35.1