[ovs-discuss] [master integration 1/6] datapath: Only call skb_checksum_setup on 2.6.18 && Xen.

[Ben Pfaff]

From: Ian Campbell <Ian.Campbell at citrix.com>

For newer kernels the checksum setup is done at the point the skb is
received in netback or netfront so there is no more need to sprinkle
skb_checksum_setup calls throughout the kernel.
---
 datapath/actions.c  |    2 +-
 datapath/datapath.c |   12 ++++++------
 datapath/datapath.h |    2 ++
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/datapath/actions.c b/datapath/actions.c
index 9b82f9e..8a3e8ab 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -96,7 +96,7 @@ modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
 		 * when we send the packet out on the wire, and it will fail at
 		 * that point because skb_checksum_setup() will not look inside
 		 * an 802.1Q header. */
-		skb_checksum_setup(skb);
+		vswitch_skb_checksum_setup(skb);
 
 		/* GSO is not implemented for packets with an 802.1Q header, so
 		 * we have to do segmentation before we add that header.
diff --git a/datapath/datapath.c b/datapath/datapath.c
index 3edba7c..926f278 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -568,8 +568,7 @@ static int dp_frame_hook(struct net_bridge_port *p, struct sk_buff **pskb)
 #error
 #endif
 
-#ifdef CONFIG_XEN
-#if LINUX_VERSION_CODE == KERNEL_VERSION(2,6,18)
+#if defined(CONFIG_XEN) && LINUX_VERSION_CODE == KERNEL_VERSION(2,6,18)
 /* This code is copied verbatim from net/dev/core.c in Xen's
  * linux-2.6.18-92.1.10.el5.xs5.0.0.394.644.  We can't call those functions
  * directly because they aren't exported. */
@@ -585,7 +584,7 @@ static int skb_pull_up_to(struct sk_buff *skb, void *ptr)
 	}
 }
 
-int skb_checksum_setup(struct sk_buff *skb)
+int vswitch_skb_checksum_setup(struct sk_buff *skb)
 {
 	if (skb->proto_csum_blank) {
 		if (skb->protocol != htons(ETH_P_IP))
@@ -616,8 +615,9 @@ int skb_checksum_setup(struct sk_buff *skb)
 out:
 	return -EPROTO;
 }
-#endif /* linux == 2.6.18 */
-#endif /* CONFIG_XEN */
+#else
+int vswitch_skb_checksum_setup(struct sk_buff *skb) { return 0; }
+#endif /* CONFIG_XEN && linux == 2.6.18 */
 
 int
 dp_output_control(struct datapath *dp, struct sk_buff *skb, int queue_no,
@@ -643,7 +643,7 @@ dp_output_control(struct datapath *dp, struct sk_buff *skb, int queue_no,
 	 * the non-Xen case, but it is difficult to trigger or test this case
 	 * there, hence the WARN_ON_ONCE().
  	 */
-	err = skb_checksum_setup(skb);
+	err = vswitch_skb_checksum_setup(skb);
  	if (err)
 		goto err_kfree_skb;
 #ifndef CHECKSUM_HW
diff --git a/datapath/datapath.h b/datapath/datapath.h
index 989dcd4..c6ec86a 100644
--- a/datapath/datapath.h
+++ b/datapath/datapath.h
@@ -144,4 +144,6 @@ static inline int skb_checksum_setup(struct sk_buff *skb)
 }
 #endif
 
+int vswitch_skb_checksum_setup(struct sk_buff *skb);
+
 #endif /* datapath.h */
-- 
1.6.3.3