2 files changed, 11 insertions, 7 deletions

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 970553cbbc8e..0b979ee4bfc0 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -395,7 +395,9 @@ struct ovs_key_nd {
  * @OVS_FLOW_ATTR_ACTIONS: Nested %OVS_ACTION_ATTR_* attributes specifying
  * the actions to take for packets that match the key.  Always present in
  * notifications.  Required for %OVS_FLOW_CMD_NEW requests, optional for
- * %OVS_FLOW_CMD_SET requests.
+ * %OVS_FLOW_CMD_SET requests.  An %OVS_FLOW_CMD_SET without
+ * %OVS_FLOW_ATTR_ACTIONS will not modify the actions.  To clear the actions,
+ * an %OVS_FLOW_ATTR_ACTIONS without any nested attributes must be given.
  * @OVS_FLOW_ATTR_STATS: &struct ovs_flow_stats giving statistics for this
  * flow.  Present in notifications if the stats would be nonzero.  Ignored in
  * requests.
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 8867d7e2d65b..90a1e5e66287 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -810,6 +810,7 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb, struct genl_info *info)
                         goto err_kfree;
                 }
         } else if (info->genlhdr->cmd == OVS_FLOW_CMD_NEW) {
+                /* OVS_FLOW_CMD_NEW must have actions. */
                 error = -EINVAL;
                 goto error;
         }
@@ -849,8 +850,6 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb, struct genl_info *info)
                 reply = ovs_flow_cmd_build_info(flow, dp, info, OVS_FLOW_CMD_NEW);
         } else {
                 /* We found a matching flow. */
-                struct sw_flow_actions *old_acts;
-
                 /* Bail out if we're not allowed to modify an existing flow.
                  * We accept NLM_F_CREATE in place of the intended NLM_F_EXCL
                  * because Generic Netlink treats the latter as a dump
@@ -866,11 +865,14 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb, struct genl_info *info)
                 if (!ovs_flow_cmp_unmasked_key(flow, &match))
                         goto err_unlock_ovs;
 
-                /* Update actions. */
-                old_acts = ovsl_dereference(flow->sf_acts);
-                rcu_assign_pointer(flow->sf_acts, acts);
-                ovs_nla_free_flow_actions(old_acts);
+                /* Update actions, if present. */
+                if (acts) {
+                        struct sw_flow_actions *old_acts;
 
+                        old_acts = ovsl_dereference(flow->sf_acts);
+                        rcu_assign_pointer(flow->sf_acts, acts);
+                        ovs_nla_free_flow_actions(old_acts);
+                }
                 reply = ovs_flow_cmd_build_info(flow, dp, info, OVS_FLOW_CMD_NEW);
 
                 /* Clear stats. */