[ovs-dev] [PATCH 2/2] datapath: Account for RHEL6.4 backports in compat layer

[Thomas Graf]

Explicitly check the availability of several kernel API functions
instead of relying on the kernel version to account for Red Hat
Enterprise Linux backports.

Signed-off-by: Thomas Graf <tgraf at redhat.com>
---
V2:
 - Move can_checksum_protocol() back into #ifdef

 acinclude.m4                                    | 7 +++++++
 datapath/linux/compat/include/asm/percpu.h      | 2 +-
 datapath/linux/compat/include/linux/netdevice.h | 2 +-
 datapath/linux/compat/include/net/netlink.h     | 8 +++++++-
 datapath/linux/compat/netdevice.c               | 2 ++
 5 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index 2703bc4..34634a2 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -224,6 +224,8 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [dev_disable_lro])
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [dev_get_stats])
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [dev_get_by_index_rcu])
+  OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [__skb_gso_segment])
+  OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [can_checksum_protocol])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/rcupdate.h], [rcu_read_lock_held], [],
                   [OVS_GREP_IFELSE([$KSRC/include/linux/rtnetlink.h],
@@ -268,11 +270,16 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
 
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [NLA_NUL_STRING])
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_get_be16])
+  OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_put_be16])
+  OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_put_be32])
+  OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_put_be64])
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_find_nested])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [ADD_ALL_VLANS_CMD],
                   [OVS_DEFINE([HAVE_VLAN_BUG_WORKAROUND])])
 
+  OVS_GREP_IFELSE([$KSRC/include/linux/percpu.h], [this_cpu_ptr])
+
   OVS_GREP_IFELSE([$KSRC/include/linux/openvswitch.h], [openvswitch_handle_frame_hook],
                   [OVS_DEFINE([HAVE_RHEL_OVS_HOOK])])
 
diff --git a/datapath/linux/compat/include/asm/percpu.h b/datapath/linux/compat/include/asm/percpu.h
index 404b937..65bce08 100644
--- a/datapath/linux/compat/include/asm/percpu.h
+++ b/datapath/linux/compat/include/asm/percpu.h
@@ -3,7 +3,7 @@
 
 #include_next <asm/percpu.h>
 
-#ifndef this_cpu_ptr
+#if !defined this_cpu_ptr && !defined HAVE_THIS_CPU_PTR
 #define this_cpu_ptr(ptr) per_cpu_ptr(ptr, smp_processor_id())
 #endif
 
diff --git a/datapath/linux/compat/include/linux/netdevice.h b/datapath/linux/compat/include/linux/netdevice.h
index 71aad87..f8240df 100644
--- a/datapath/linux/compat/include/linux/netdevice.h
+++ b/datapath/linux/compat/include/linux/netdevice.h
@@ -158,7 +158,7 @@ static inline int rpl_netif_needs_gso(struct sk_buff *skb, int features)
 typedef u32 netdev_features_t;
 #endif
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,9,0)
+#ifndef HAVE___SKB_GSO_SEGMENT
 static inline struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
 						netdev_features_t features,
 						bool tx_path)
diff --git a/datapath/linux/compat/include/net/netlink.h b/datapath/linux/compat/include/net/netlink.h
index 9616ea9..308cd69 100644
--- a/datapath/linux/compat/include/net/netlink.h
+++ b/datapath/linux/compat/include/net/netlink.h
@@ -85,15 +85,21 @@ static inline __be64 nla_get_be64(const struct nlattr *nla)
 }
 #endif
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,5,0)
+#ifndef HAVE_NLA_PUT_BE16
 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 {
 	return nla_put(skb, attrtype, sizeof(__be16), &value);
 }
+#endif
+
+#ifndef HAVE_NLA_PUT_BE32
 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 {
 	return nla_put(skb, attrtype, sizeof(__be32), &value);
 }
+#endif
+
+#ifndef HAVE_NLA_PUT_BE64
 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value)
 {
 	return nla_put(skb, attrtype, sizeof(__be64), &value);
diff --git a/datapath/linux/compat/netdevice.c b/datapath/linux/compat/netdevice.c
index 9e92eeb..d26fb5e 100644
--- a/datapath/linux/compat/netdevice.c
+++ b/datapath/linux/compat/netdevice.c
@@ -2,6 +2,7 @@
 #include <linux/if_vlan.h>
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,38)
+#ifndef HAVE_CAN_CHECKSUM_PROTOCOL
 static bool can_checksum_protocol(unsigned long features, __be16 protocol)
 {
 	return  ((features & NETIF_F_GEN_CSUM) ||
@@ -12,6 +13,7 @@ static bool can_checksum_protocol(unsigned long features, __be16 protocol)
 		((features & NETIF_F_FCOE_CRC) &&
 				protocol == htons(ETH_P_FCOE)));
 }
+#endif
 
 static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 {
-- 
1.7.11.7