datapath: move make_writable helper into common code

note that skb_make_writable already exists in net/netfilter/core.c
but does something slightly different.

Upstream: e219512 ("net: move make_writable helper into common code")
Signed-off-by: Thomas Graf <tgraf@noironetworks.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>

Author: Thomas Graf

acinclude.m4

@@ -345,6 +345,7 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [int.skb_zerocopy(],
                   [OVS_DEFINE([HAVE_SKB_ZEROCOPY])])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [l4_rxhash])
+  OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_ensure_writable])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/types.h], [bool],
                   [OVS_DEFINE([HAVE_BOOL_TYPE])])

datapath/actions.c

@@ -122,17 +122,6 @@ static bool is_flow_key_valid(const struct sw_flow_key *key)
 	return !!key->eth.type;
 }
 
-static int make_writable(struct sk_buff *skb, int write_len)
-{
-	if (!pskb_may_pull(skb, write_len))
-		return -ENOMEM;
-
-	if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
-		return 0;
-
-	return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
-}
-
 static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 		     const struct ovs_action_push_mpls *mpls)
 {
@@ -174,7 +163,7 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	struct ethhdr *hdr;
 	int err;
 
-	err = make_writable(skb, skb->mac_len + MPLS_HLEN);
+	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
 	if (unlikely(err))
 		return err;
 
@@ -207,7 +196,7 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	__be32 *stack;
 	int err;
 
-	err = make_writable(skb, skb->mac_len + MPLS_HLEN);
+	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
 	if (unlikely(err))
 		return err;
 
@@ -229,7 +218,7 @@ static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 	struct vlan_hdr *vhdr;
 	int err;
 
-	err = make_writable(skb, VLAN_ETH_HLEN);
+	err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
 	if (unlikely(err))
 		return err;
 
@@ -313,7 +302,7 @@ static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *key,
 			const struct ovs_key_ethernet *eth_key)
 {
 	int err;
-	err = make_writable(skb, ETH_HLEN);
+	err = skb_ensure_writable(skb, ETH_HLEN);
 	if (unlikely(err))
 		return err;
 
@@ -419,8 +408,8 @@ static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *key,
 	struct iphdr *nh;
 	int err;
 
-	err = make_writable(skb, skb_network_offset(skb) +
-				 sizeof(struct iphdr));
+	err = skb_ensure_writable(skb, skb_network_offset(skb) +
+				  sizeof(struct iphdr));
 	if (unlikely(err))
 		return err;
 
@@ -457,8 +446,8 @@ static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
 	__be32 *saddr;
 	__be32 *daddr;
 
-	err = make_writable(skb, skb_network_offset(skb) +
-			    sizeof(struct ipv6hdr));
+	err = skb_ensure_writable(skb, skb_network_offset(skb) +
+				  sizeof(struct ipv6hdr));
 	if (unlikely(err))
 		return err;
 
@@ -500,7 +489,7 @@ static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
 	return 0;
 }
 
-/* Must follow make_writable() since that can move the skb data. */
+/* Must follow skb_ensure_writable() since that can move the skb data. */
 static void set_tp_port(struct sk_buff *skb, __be16 *port,
 			 __be16 new_port, __sum16 *check)
 {
@@ -530,8 +519,8 @@ static int set_udp(struct sk_buff *skb, struct sw_flow_key *key,
 	struct udphdr *uh;
 	int err;
 
-	err = make_writable(skb, skb_transport_offset(skb) +
-				 sizeof(struct udphdr));
+	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
+				  sizeof(struct udphdr));
 	if (unlikely(err))
 		return err;
 
@@ -555,8 +544,8 @@ static int set_tcp(struct sk_buff *skb, struct sw_flow_key *key,
 	struct tcphdr *th;
 	int err;
 
-	err = make_writable(skb, skb_transport_offset(skb) +
-				 sizeof(struct tcphdr));
+	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
+				  sizeof(struct tcphdr));
 	if (unlikely(err))
 		return err;
 
@@ -581,7 +570,7 @@ static int set_sctp(struct sk_buff *skb, struct sw_flow_key *key,
 	int err;
 	unsigned int sctphoff = skb_transport_offset(skb);
 
-	err = make_writable(skb, sctphoff + sizeof(struct sctphdr));
+	err = skb_ensure_writable(skb, sctphoff + sizeof(struct sctphdr));
 	if (unlikely(err))
 		return err;
 

datapath/linux/compat/include/linux/skbuff.h

@@ -324,4 +324,9 @@ static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
 }
 #endif
 
+#ifndef HAVE_SKB_ENSURE_WRITABLE
+#define skb_ensure_writable rpl_skb_ensure_writable
+int skb_ensure_writable(struct sk_buff *skb, int write_len);
+#endif
+
 #endif

datapath/linux/compat/skbuff-openvswitch.c

@@ -124,3 +124,16 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 }
 #endif
 #endif
+
+#ifndef HAVE_SKB_ENSURE_WRITABLE
+int skb_ensure_writable(struct sk_buff *skb, int write_len)
+{
+	if (!pskb_may_pull(skb, write_len))
+		return -ENOMEM;
+
+	if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
+		return 0;
+
+	return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
+}
+#endif