netdev - [PATCH RFC net-next 14/19] net: dsa: tag_mtk: split out common tag accessors

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Message-Id: <20191230143028.27313-15-alobakin@dlink.ru>
Date:   Mon, 30 Dec 2019 17:30:22 +0300
From:   Alexander Lobakin <alobakin@...nk.ru>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     Edward Cree <ecree@...arflare.com>, Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Hauke Mehrtens <hauke@...ke-m.de>,
        Sean Wang <sean.wang@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Jiri Pirko <jiri@...lanox.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Alexander Lobakin <alobakin@...nk.ru>,
        Taehee Yoo <ap420073@...il.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Song Liu <songliubraving@...com>,
        Matteo Croce <mcroce@...hat.com>,
        Jakub Sitnicki <jakub@...udflare.com>,
        Paul Blakey <paulb@...lanox.com>,
        Yoshiki Komachi <komachi.yoshiki@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: [PATCH RFC net-next 14/19] net: dsa: tag_mtk: split out common tag accessors

Misc: fix identation of MTK_HDR_LEN and make use of it in
mtk_tag_flow_dissect() instead of open-coded value.

Signed-off-by: Alexander Lobakin <alobakin@...nk.ru>
---
 net/dsa/tag_mtk.c | 40 +++++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index c3ad7b7b142a..b926ffdf5fb5 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -10,12 +10,27 @@
 
 #include "dsa_priv.h"
 
-#define MTK_HDR_LEN		4
+#define MTK_HDR_LEN			4
 #define MTK_HDR_XMIT_UNTAGGED		0
 #define MTK_HDR_XMIT_TAGGED_TPID_8100	1
 #define MTK_HDR_RECV_SOURCE_PORT_MASK	GENMASK(2, 0)
 #define MTK_HDR_XMIT_DP_BIT_MASK	GENMASK(5, 0)
 
+static inline int mtk_tag_source_port(const u8 *data)
+{
+	/* The MTK header is added by the switch between src addr
+	 * and ethertype at this point, skb->data points to 2 bytes
+	 * after src addr so header should be 2 bytes right before.
+	 * The source port field is in the second byte of the tag.
+	 */
+	return *(data - 1) & MTK_HDR_RECV_SOURCE_PORT_MASK;
+}
+
+static inline __be16 mtk_tag_encap_proto(const u8 *data)
+{
+	return *(__be16 *)(data + 2);
+}
+
 static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
 				    struct net_device *dev)
 {
@@ -60,17 +75,15 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 				   struct packet_type *pt)
 {
 	int port;
-	__be16 *phdr, hdr;
 
 	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
 		return NULL;
 
-	/* The MTK header is added by the switch between src addr
-	 * and ethertype at this point, skb->data points to 2 bytes
-	 * after src addr so header should be 2 bytes right before.
-	 */
-	phdr = (__be16 *)(skb->data - 2);
-	hdr = ntohs(*phdr);
+	port = mtk_tag_source_port(skb->data);
+
+	skb->dev = dsa_master_find_slave(dev, 0, port);
+	if (!skb->dev)
+		return NULL;
 
 	/* Remove MTK tag and recalculate checksum. */
 	skb_pull_rcsum(skb, MTK_HDR_LEN);
@@ -79,21 +92,14 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 		skb->data - ETH_HLEN - MTK_HDR_LEN,
 		2 * ETH_ALEN);
 
-	/* Get source port information */
-	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
-
-	skb->dev = dsa_master_find_slave(dev, 0, port);
-	if (!skb->dev)
-		return NULL;
-
 	return skb;
 }
 
 static void mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
 				 int *offset)
 {
-	*offset = 4;
-	*proto = ((__be16 *)skb->data)[1];
+	*offset = MTK_HDR_LEN;
+	*proto = mtk_tag_encap_proto(skb->data);
 }
 
 static const struct dsa_device_ops mtk_netdev_ops = {
-- 
2.24.1