datapath: Support for Linux kernel 3.9.

In certain cases we need to ensure we save off skb->cb before calling __skb_gso_segment() since in kernels >= 3.9 skb->cb is used by this routine. Signed-off-by: Pravin B Shelar <[email protected]> Signed-off-by: Kyle Mestery <[email protected]> Signed-off-by: Jesse Gross <[email protected]>
amuessig · Jul 31, 2013 · 7ceda29 · 7ceda29
1 parent 6a69010
commit 7ceda29
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Showing 6 changed files with 18 additions and 3 deletions.
diff --git a/FAQ b/FAQ
@@ -148,7 +148,7 @@ A: The following table lists the Linux kernel versions against which the
        1.9.x      2.6.18 to 3.8
        1.10.x     2.6.18 to 3.8
        1.11.x     2.6.18 to 3.8
-       1.12.x     2.6.18 to 3.8
+       1.12.x     2.6.18 to 3.9
 
    Open vSwitch userspace should also work with the Linux kernel module
    built into Linux 3.3 and later.

diff --git a/NEWS b/NEWS
@@ -19,6 +19,7 @@ v1.12.0 - xx xxx xxxx
       through database paths (e.g. Private key option with the database name
       should look like "--private-key=db:Open_vSwitch,SSL,private_key").
     - Added ovs-dev.py, a utility script helpful for Open vSwitch developers.
+    - Support for Linux kernels up to 3.9
 
 
 v1.11.0 - xx xxx xxxx

diff --git a/datapath/datapath.c b/datapath/datapath.c
@@ -63,8 +63,8 @@
 #include "vport-netdev.h"
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
-    LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0)
-#error Kernels before 2.6.18 or after 3.8 are not supported by this version of Open vSwitch.
+    LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0)
+#error Kernels before 2.6.18 or after 3.9 are not supported by this version of Open vSwitch.
 #endif
 
 #define REHASH_FLOW_INTERVAL (10 * 60 * HZ)

diff --git a/datapath/linux/compat/gso.c b/datapath/linux/compat/gso.c
@@ -65,6 +65,7 @@ static struct sk_buff *tnl_skb_gso_segment(struct sk_buff *skb,
 	struct sk_buff *skb1 = skb;
 	struct sk_buff *segs;
 	__be16 proto = skb->protocol;
+	char cb[sizeof(skb->cb)];
 
 	/* setup whole inner packet to get protocol. */
 	__skb_pull(skb, mac_offset);
@@ -76,6 +77,10 @@ static struct sk_buff *tnl_skb_gso_segment(struct sk_buff *skb,
 	skb_reset_network_header(skb);
 	skb_reset_transport_header(skb);
 
+	/* From 3.9 kernel skb->cb is used by skb gso. Therefore
+	 * make copy of it to restore it back. */
+	memcpy(cb, skb->cb, sizeof(cb));
+
 	segs = __skb_gso_segment(skb, 0, tx_path);
 	if (!segs || IS_ERR(segs))
 		goto free;
@@ -89,6 +94,7 @@ static struct sk_buff *tnl_skb_gso_segment(struct sk_buff *skb,
 		skb->mac_len = 0;
 
 		memcpy(ip_hdr(skb), iph, pkt_hlen);
+		memcpy(skb->cb, cb, sizeof(cb));
 		if (OVS_GSO_CB(skb)->fix_segment)
 			OVS_GSO_CB(skb)->fix_segment(skb);
 

diff --git a/datapath/tunnel.c b/datapath/tunnel.c
@@ -144,6 +144,9 @@ static struct sk_buff *handle_offloads(struct sk_buff *skb)
 
 	if (skb_is_gso(skb)) {
 		struct sk_buff *nskb;
+		char cb[sizeof(skb->cb)];
+
+		memcpy(cb, skb->cb, sizeof(cb));
 
 		nskb = __skb_gso_segment(skb, 0, false);
 		if (IS_ERR(nskb)) {
@@ -153,6 +156,10 @@ static struct sk_buff *handle_offloads(struct sk_buff *skb)
 
 		consume_skb(skb);
 		skb = nskb;
+		while (nskb) {
+			memcpy(nskb->cb, cb, sizeof(cb));
+			nskb = nskb->next;
+		}
 	} else if (get_ip_summed(skb) == OVS_CSUM_PARTIAL) {
 		/* Pages aren't locked and could change at any time.
 		 * If this happens after we compute the checksum, the

diff --git a/debian/changelog b/debian/changelog
@@ -23,6 +23,7 @@ openvswitch (1.12.0-1) unstable; urgency=low
       through database paths (e.g. Private key option with the database name
       should look like "--private-key=db:Open_vSwitch,SSL,private_key").
     - Added ovs-dev.py, a utility script helpful for Open vSwitch developers.
+    - Support for Linux kernels up to 3.9
 
  -- Open vSwitch team <[email protected]>  Tue, 03 Jul 2013 15:02:34 -0700