[RFC PATCH 1/4] net: add new helper to update an already registered offload

[Paolo Abeni <pabeni@redhat.com>]

This will allow us to enable/disable UDP GRO at runtime in
a later patch.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 include/net/protocol.h |  4 ++++
 net/ipv4/protocol.c    | 13 +++++++++----
 net/ipv6/protocol.c    | 13 +++++++++----
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/include/net/protocol.h b/include/net/protocol.h
index 4fc75f7ae23b..aa77e7feffab 100644
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -104,6 +104,8 @@ extern struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS];
 int inet_add_protocol(const struct net_protocol *prot, unsigned char num);
 int inet_del_protocol(const struct net_protocol *prot, unsigned char num);
 int inet_add_offload(const struct net_offload *prot, unsigned char num);
+int inet_update_offload(const struct net_offload *old_prot,
+			const struct net_offload *new_prot, unsigned char num);
 int inet_del_offload(const struct net_offload *prot, unsigned char num);
 void inet_register_protosw(struct inet_protosw *p);
 void inet_unregister_protosw(struct inet_protosw *p);
@@ -115,6 +117,8 @@ int inet6_register_protosw(struct inet_protosw *p);
 void inet6_unregister_protosw(struct inet_protosw *p);
 #endif
 int inet6_add_offload(const struct net_offload *prot, unsigned char num);
+int inet6_update_offload(const struct net_offload *old_prot,
+			 const struct net_offload *new_prot, unsigned char num);
 int inet6_del_offload(const struct net_offload *prot, unsigned char num);
 
 #endif	/* _PROTOCOL_H */
diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c
index 32a691b7ce2c..b60f1686b918 100644
--- a/net/ipv4/protocol.c
+++ b/net/ipv4/protocol.c
@@ -65,12 +65,17 @@ int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
 }
 EXPORT_SYMBOL(inet_del_protocol);
 
-int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
+int inet_update_offload(const struct net_offload *old_prot,
+			const struct net_offload *new_prot,
+			unsigned char protocol)
 {
-	int ret;
+	return (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
+		        old_prot, new_prot) == old_prot) ? 0 : -1;
+}
 
-	ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
-		       prot, NULL) == prot) ? 0 : -1;
+int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
+{
+	int ret = inet_update_offload(prot, NULL, protocol);
 
 	synchronize_net();
 
diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c
index b5d54d4f995c..9ee6aff1f3fa 100644
--- a/net/ipv6/protocol.c
+++ b/net/ipv6/protocol.c
@@ -60,12 +60,17 @@ int inet6_add_offload(const struct net_offload *prot, unsigned char protocol)
 }
 EXPORT_SYMBOL(inet6_add_offload);
 
-int inet6_del_offload(const struct net_offload *prot, unsigned char protocol)
+int inet6_update_offload(const struct net_offload *old_prot,
+			 const struct net_offload *new_prot,
+			 unsigned char protocol)
 {
-	int ret;
+	return (cmpxchg((const struct net_offload **)&inet6_offloads[protocol],
+		        old_prot, new_prot) == old_prot) ? 0 : -1;
+}
 
-	ret = (cmpxchg((const struct net_offload **)&inet6_offloads[protocol],
-		       prot, NULL) == prot) ? 0 : -1;
+int inet6_del_offload(const struct net_offload *prot, unsigned char protocol)
+{
+	int ret = inet6_update_offload(prot, NULL, protocol);
 
 	synchronize_net();
 
-- 
2.17.1