[PATCH RFC net-next 01/19] net: dsa: make .flow_dissect() callback returning void

[Alexander Lobakin]

There are no tag protocols which return non-zero values from
flow_dissect() callback. Remove it to simplify code and save some
object size.
If a particular tagger can't calculate offset and proto for some
reason, it can simply leave the original values untouched.

Signed-off-by: Alexander Lobakin <alobakin@xxxxxxxx>
---
 include/net/dsa.h         | 5 ++---
 net/core/flow_dissector.c | 8 ++++----
 net/dsa/tag_dsa.c         | 5 ++---
 net/dsa/tag_edsa.c        | 5 ++---
 net/dsa/tag_mtk.c         | 6 ++----
 net/dsa/tag_qca.c         | 6 ++----
 6 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index da5578db228e..633d9894ab87 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -72,8 +72,8 @@ struct dsa_device_ops {
 	struct sk_buff *(*xmit)(struct sk_buff *skb, struct net_device *dev);
 	struct sk_buff *(*rcv)(struct sk_buff *skb, struct net_device *dev,
 			       struct packet_type *pt);
-	int (*flow_dissect)(const struct sk_buff *skb, __be16 *proto,
-			    int *offset);
+	void (*flow_dissect)(const struct sk_buff *skb, __be16 *proto,
+			     int *offset);
 	/* Used to determine which traffic should match the DSA filter in
 	 * eth_type_trans, and which, if any, should bypass it and be processed
 	 * as regular on the master net device.
@@ -774,4 +774,3 @@ static struct dsa_tag_driver *dsa_tag_driver_array[] =	{		\
 };									\
 module_dsa_tag_drivers(dsa_tag_driver_array)
 #endif
-
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 2dbbb030fbed..2c9d8c7c76b3 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -971,12 +971,12 @@ bool __skb_flow_dissect(const struct net *net,
 #if IS_ENABLED(CONFIG_NET_DSA)
 		if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) &&
 			     proto == htons(ETH_P_XDSA))) {
-			const struct dsa_device_ops *ops;
+			typeof_member(struct dsa_device_ops, flow_dissect) fd;
 			int offset = 0;
 
-			ops = skb->dev->dsa_ptr->tag_ops;
-			if (ops->flow_dissect &&
-			    !ops->flow_dissect(skb, &proto, &offset)) {
+			fd = skb->dev->dsa_ptr->tag_ops->flow_dissect;
+			if (fd) {
+				fd(skb, &proto, &offset);
 				hlen -= offset;
 				nhoff += offset;
 			}
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index 7ddec9794477..ef15aee58dfc 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -142,12 +142,11 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	return skb;
 }
 
-static int dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
-				int *offset)
+static void dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
+				 int *offset)
 {
 	*offset = 4;
 	*proto = ((__be16 *)skb->data)[1];
-	return 0;
 }
 
 static const struct dsa_device_ops dsa_netdev_ops = {
diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
index e8eaa804ccb9..37a99254b411 100644
--- a/net/dsa/tag_edsa.c
+++ b/net/dsa/tag_edsa.c
@@ -161,12 +161,11 @@ static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	return skb;
 }
 
-static int edsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
-				 int *offset)
+static void edsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
+				  int *offset)
 {
 	*offset = 8;
 	*proto = ((__be16 *)skb->data)[3];
-	return 0;
 }
 
 static const struct dsa_device_ops edsa_netdev_ops = {
diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index b5705cba8318..c3ad7b7b142a 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -89,13 +89,11 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 	return skb;
 }
 
-static int mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
-				int *offset)
+static void mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
+				 int *offset)
 {
 	*offset = 4;
 	*proto = ((__be16 *)skb->data)[1];
-
-	return 0;
 }
 
 static const struct dsa_device_ops mtk_netdev_ops = {
diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index c95885215525..8e2dbaaffe59 100644
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -90,13 +90,11 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 	return skb;
 }
 
-static int qca_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
-                                int *offset)
+static void qca_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
+				 int *offset)
 {
 	*offset = QCA_HDR_LEN;
 	*proto = ((__be16 *)skb->data)[0];
-
-	return 0;
 }
 
 static const struct dsa_device_ops qca_netdev_ops = {
-- 
2.24.1