[ovs-dev] [PATCH] datapath: gre: Fix kernel 3.11 compatibility.

[Pravin B Shelar]

On 3.11 kernel, gre module exports IP_GRE demux API, ovs needs
to use it to register for GRE protocol handler.

Reported-by:  Nithin Nayak Sujir <nsujir at broadcom.com>
Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
---
 datapath/linux/compat/gre.c             |    8 ++++++--
 datapath/linux/compat/include/net/gre.h |    4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/datapath/linux/compat/gre.c b/datapath/linux/compat/gre.c
index 582bd94..f35f11f 100644
--- a/datapath/linux/compat/gre.c
+++ b/datapath/linux/compat/gre.c
@@ -39,8 +39,6 @@
 
 #include "gso.h"
 
-static struct gre_cisco_protocol __rcu *gre_cisco_proto;
-
 static void gre_csum_fix(struct sk_buff *skb)
 {
 	struct gre_base_hdr *greh;
@@ -114,6 +112,8 @@ void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 	}
 }
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,11,0)
+
 static __sum16 check_checksum(struct sk_buff *skb)
 {
 	__sum16 csum = 0;
@@ -197,6 +197,8 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	return iptunnel_pull_header(skb, hdr_len, tpi->proto);
 }
 
+static struct gre_cisco_protocol __rcu *gre_cisco_proto;
+
 static int gre_cisco_rcv(struct sk_buff *skb)
 {
 	struct tnl_ptk_info tpi;
@@ -354,4 +356,6 @@ int gre_cisco_unregister(struct gre_cisco_protocol *proto)
 	return ret;
 }
 
+#endif /* 3.11 */
+
 #endif /* CONFIG_NET_IPGRE_DEMUX */
diff --git a/datapath/linux/compat/include/net/gre.h b/datapath/linux/compat/include/net/gre.h
index 5b17dcc..93cb565 100644
--- a/datapath/linux/compat/include/net/gre.h
+++ b/datapath/linux/compat/include/net/gre.h
@@ -73,6 +73,8 @@ static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)
 }
 #endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0) */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,11,0)
+/* GRE demux not available, implement our own demux. */
 #define MAX_GRE_PROTO_PRIORITY 255
 #define gre_cisco_protocol rpl_gre_cisco_protocol
 
@@ -87,6 +89,8 @@ int gre_cisco_register(struct gre_cisco_protocol *proto);
 #define gre_cisco_unregister rpl_gre_cisco_unregister
 int gre_cisco_unregister(struct gre_cisco_protocol *proto);
 
+#endif
+
 #define gre_build_header rpl_gre_build_header
 void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 		      int hdr_len);
-- 
1.7.1