openvswitch: Factor out allocation and verification of actions.

As the size of the flow key grows, it can put some pressure on the
stack. This is particularly true in ovs_flow_cmd_set(), which needs several
copies of the key on the stack. One of those uses is logically separate,
so this factors it out to reduce stack pressure and improve readibility.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index f6bd93d..010125c 100644 (file)
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -933,11 +933,34 @@ error:
        return error;
 }
 
+static struct sw_flow_actions *get_flow_actions(const struct nlattr *a,
+                                               const struct sw_flow_key *key,
+                                               const struct sw_flow_mask *mask)
+{
+       struct sw_flow_actions *acts;
+       struct sw_flow_key masked_key;
+       int error;
+
+       acts = ovs_nla_alloc_flow_actions(nla_len(a));
+       if (IS_ERR(acts))
+               return acts;
+
+       ovs_flow_mask_key(&masked_key, key, mask);
+       error = ovs_nla_copy_actions(a, &masked_key, 0, &acts);
+       if (error) {
+               OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
+               kfree(acts);
+               return ERR_PTR(error);
+       }
+
+       return acts;
+}
+
 static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 {
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
-       struct sw_flow_key key, masked_key;
+       struct sw_flow_key key;
        struct sw_flow *flow;
        struct sw_flow_mask mask;
        struct sk_buff *reply = NULL;
@@ -959,17 +982,10 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 
        /* Validate actions. */
        if (a[OVS_FLOW_ATTR_ACTIONS]) {
-               acts = ovs_nla_alloc_flow_actions(nla_len(a[OVS_FLOW_ATTR_ACTIONS]));
-               error = PTR_ERR(acts);
-               if (IS_ERR(acts))
+               acts = get_flow_actions(a[OVS_FLOW_ATTR_ACTIONS], &key, &mask);
+               if (IS_ERR(acts)) {
+                       error = PTR_ERR(acts);
                        goto error;
-
-               ovs_flow_mask_key(&masked_key, &key, &mask);
-               error = ovs_nla_copy_actions(a[OVS_FLOW_ATTR_ACTIONS],
-                                            &masked_key, 0, &acts);
-               if (error) {
-                       OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
-                       goto err_kfree_acts;
                }
        }