1 files changed, 39 insertions, 11 deletions

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index e70d8b18e962..fe5cda0deb39 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -38,7 +38,7 @@
 #include "vport.h"
 
 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
-                        const struct nlattr *attr, int len, bool keep_skb);
+                              const struct nlattr *attr, int len);
 
 static int make_writable(struct sk_buff *skb, int write_len)
 {
@@ -434,11 +434,17 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
         return ovs_dp_upcall(dp, skb, &upcall);
 }
 
+static bool last_action(const struct nlattr *a, int rem)
+{
+        return a->nla_len == rem;
+}
+
 static int sample(struct datapath *dp, struct sk_buff *skb,
                   const struct nlattr *attr)
 {
         const struct nlattr *acts_list = NULL;
         const struct nlattr *a;
+        struct sk_buff *sample_skb;
         int rem;
 
         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
@@ -455,8 +461,34 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
                 }
         }
 
-        return do_execute_actions(dp, skb, nla_data(acts_list),
-                                                 nla_len(acts_list), true);
+        rem = nla_len(acts_list);
+        a = nla_data(acts_list);
+
+        /* Actions list is either empty or only contains a single user-space
+         * action, the latter being a special case as it is the only known
+         * usage of the sample action.
+         * In these special cases don't clone the skb as there are no
+         * side-effects in the nested actions.
+         * Otherwise, clone in case the nested actions have side effects.
+         */
+        if (likely(rem == 0 || (nla_type(a) == OVS_ACTION_ATTR_USERSPACE &&
+                                last_action(a, rem)))) {
+                sample_skb = skb;
+                skb_get(skb);
+        } else {
+                sample_skb = skb_clone(skb, GFP_ATOMIC);
+                if (!sample_skb) /* Skip sample action when out of memory. */
+                        return 0;
+        }
+
+        /* Note that do_execute_actions() never consumes skb.
+         * In the case where skb has been cloned above it is the clone that
+         * is consumed.  Otherwise the skb_get(skb) call prevents
+         * consumption by do_execute_actions(). Thus, it is safe to simply
+         * return the error code and let the caller (also
+         * do_execute_actions()) free skb on error.
+         */
+        return do_execute_actions(dp, sample_skb, a, rem);
 }
 
 static int execute_set_action(struct sk_buff *skb,
@@ -507,7 +539,7 @@ static int execute_set_action(struct sk_buff *skb,
 
 /* Execute a list of actions against 'skb'. */
 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
-                        const struct nlattr *attr, int len, bool keep_skb)
+                              const struct nlattr *attr, int len)
 {
         /* Every output action needs a separate clone of 'skb', but the common
          * case is just a single output action, so that doing a clone and
@@ -562,12 +594,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
                 }
         }
 
-        if (prev_port != -1) {
-                if (keep_skb)
-                        skb = skb_clone(skb, GFP_ATOMIC);
-
+        if (prev_port != -1)
                 do_output(dp, skb, prev_port);
-        } else if (!keep_skb)
+        else
                 consume_skb(skb);
 
         return 0;
@@ -579,6 +608,5 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
         struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
 
         OVS_CB(skb)->tun_key = NULL;
-        return do_execute_actions(dp, skb, acts->actions,
-                                         acts->actions_len, false);
+        return do_execute_actions(dp, skb, acts->actions, acts->actions_len);
 }