openvswitch: Minimize ovs_flow_cmd_new|set critical sections.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 22665a6..6bc9d94 100644 (file)
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -796,8 +796,7 @@ static int ovs_flow_cmd_new(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 *flow;
+       struct sw_flow *flow, *new_flow;
        struct sw_flow_mask mask;
        struct sk_buff *reply;
        struct datapath *dp;
@@ -805,61 +804,77 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
        struct sw_flow_match match;
        int error;
 
-       /* Extract key. */
+       /* Must have key and actions. */
        error = -EINVAL;
        if (!a[OVS_FLOW_ATTR_KEY])
                goto error;
+       if (!a[OVS_FLOW_ATTR_ACTIONS])
+               goto error;
 
-       ovs_match_init(&match, &key, &mask);
+       /* Most of the time we need to allocate a new flow, do it before
+        * locking.
+        */
+       new_flow = ovs_flow_alloc();
+       if (IS_ERR(new_flow)) {
+               error = PTR_ERR(new_flow);
+               goto error;
+       }
+
+       /* Extract key. */
+       ovs_match_init(&match, &new_flow->unmasked_key, &mask);
        error = ovs_nla_get_match(&match,
                                  a[OVS_FLOW_ATTR_KEY], a[OVS_FLOW_ATTR_MASK]);
        if (error)
-               goto error;
+               goto err_kfree_flow;
 
-       /* Validate actions. */
-       error = -EINVAL;
-       if (!a[OVS_FLOW_ATTR_ACTIONS])
-               goto error;
+       ovs_flow_mask_key(&new_flow->key, &new_flow->unmasked_key, &mask);
 
+       /* Validate actions. */
        acts = ovs_nla_alloc_flow_actions(nla_len(a[OVS_FLOW_ATTR_ACTIONS]));
        error = PTR_ERR(acts);
        if (IS_ERR(acts))
-               goto error;
+               goto err_kfree_flow;
 
-       ovs_flow_mask_key(&masked_key, &key, &mask);
-       error = ovs_nla_copy_actions(a[OVS_FLOW_ATTR_ACTIONS],
-                                    &masked_key, 0, &acts);
+       error = ovs_nla_copy_actions(a[OVS_FLOW_ATTR_ACTIONS], &new_flow->key,
+                                    0, &acts);
        if (error) {
                OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
-               goto err_kfree;
+               goto err_kfree_acts;
+       }
+
+       reply = ovs_flow_cmd_alloc_info(acts, info, false);
+       if (IS_ERR(reply)) {
+               error = PTR_ERR(reply);
+               goto err_kfree_acts;
        }
 
        ovs_lock();
        dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
-       error = -ENODEV;
-       if (!dp)
+       if (unlikely(!dp)) {
+               error = -ENODEV;
                goto err_unlock_ovs;
-
+       }
        /* Check if this is a duplicate flow */
-       flow = ovs_flow_tbl_lookup(&dp->table, &key);
-       if (!flow) {
-               /* Allocate flow. */
-               flow = ovs_flow_alloc();
-               if (IS_ERR(flow)) {
-                       error = PTR_ERR(flow);
-                       goto err_unlock_ovs;
-               }
-
-               flow->key = masked_key;
-               flow->unmasked_key = key;
-               rcu_assign_pointer(flow->sf_acts, acts);
+       flow = ovs_flow_tbl_lookup(&dp->table, &new_flow->unmasked_key);
+       if (likely(!flow)) {
+               rcu_assign_pointer(new_flow->sf_acts, acts);
 
                /* Put flow in bucket. */
-               error = ovs_flow_tbl_insert(&dp->table, flow, &mask);
-               if (error) {
+               error = ovs_flow_tbl_insert(&dp->table, new_flow, &mask);
+               if (unlikely(error)) {
                        acts = NULL;
-                       goto err_flow_free;
+                       goto err_unlock_ovs;
                }
+
+               if (unlikely(reply)) {
+                       error = ovs_flow_cmd_fill_info(new_flow,
+                                                      ovs_header->dp_ifindex,
+                                                      reply, info->snd_portid,
+                                                      info->snd_seq, 0,
+                                                      OVS_FLOW_CMD_NEW);
+                       BUG_ON(error < 0);
+               }
+               ovs_unlock();
        } else {
                struct sw_flow_actions *old_acts;
 
@@ -869,39 +884,45 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
                 * request.  We also accept NLM_F_EXCL in case that bug ever
                 * gets fixed.
                 */
-               error = -EEXIST;
-               if (info->nlhdr->nlmsg_flags & (NLM_F_CREATE | NLM_F_EXCL))
+               if (unlikely(info->nlhdr->nlmsg_flags & (NLM_F_CREATE
+                                                        | NLM_F_EXCL))) {
+                       error = -EEXIST;
                        goto err_unlock_ovs;
-
+               }
                /* The unmasked key has to be the same for flow updates. */
-               if (!ovs_flow_cmp_unmasked_key(flow, &match))
+               if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
+                       error = -EEXIST;
                        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);
-       }
 
-       reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex,
-                                       info, OVS_FLOW_CMD_NEW, false);
-       ovs_unlock();
+               if (unlikely(reply)) {
+                       error = ovs_flow_cmd_fill_info(flow,
+                                                      ovs_header->dp_ifindex,
+                                                      reply, info->snd_portid,
+                                                      info->snd_seq, 0,
+                                                      OVS_FLOW_CMD_NEW);
+                       BUG_ON(error < 0);
+               }
+               ovs_unlock();
 
-       if (reply) {
-               if (!IS_ERR(reply))
-                       ovs_notify(&dp_flow_genl_family, reply, info);
-               else
-                       netlink_set_err(sock_net(skb->sk)->genl_sock, 0, 0,
-                                       PTR_ERR(reply));
+               ovs_nla_free_flow_actions(old_acts);
+               ovs_flow_free(new_flow, false);
        }
+
+       if (reply)
+               ovs_notify(&dp_flow_genl_family, reply, info);
        return 0;
 
-err_flow_free:
-       ovs_flow_free(flow, false);
 err_unlock_ovs:
        ovs_unlock();
-err_kfree:
+       kfree_skb(reply);
+err_kfree_acts:
        kfree(acts);
+err_kfree_flow:
+       ovs_flow_free(new_flow, false);
 error:
        return error;
 }
@@ -915,7 +936,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
        struct sw_flow_mask mask;
        struct sk_buff *reply = NULL;
        struct datapath *dp;
-       struct sw_flow_actions *acts = NULL;
+       struct sw_flow_actions *old_acts = NULL, *acts = NULL;
        struct sw_flow_match match;
        int error;
 
@@ -942,56 +963,75 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
                                             &masked_key, 0, &acts);
                if (error) {
                        OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
-                       goto err_kfree;
+                       goto err_kfree_acts;
+               }
+       }
+
+       /* Can allocate before locking if have acts. */
+       if (acts) {
+               reply = ovs_flow_cmd_alloc_info(acts, info, false);
+               if (IS_ERR(reply)) {
+                       error = PTR_ERR(reply);
+                       goto err_kfree_acts;
                }
        }
 
        ovs_lock();
        dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
-       error = -ENODEV;
-       if (!dp)
+       if (unlikely(!dp)) {
+               error = -ENODEV;
                goto err_unlock_ovs;
-
+       }
        /* Check that the flow exists. */
        flow = ovs_flow_tbl_lookup(&dp->table, &key);
-       error = -ENOENT;
-       if (!flow)
+       if (unlikely(!flow)) {
+               error = -ENOENT;
                goto err_unlock_ovs;
-
+       }
        /* The unmasked key has to be the same for flow updates. */
-       error = -EEXIST;
-       if (!ovs_flow_cmp_unmasked_key(flow, &match))
+       if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
+               error = -EEXIST;
                goto err_unlock_ovs;
-
+       }
        /* Update actions, if present. */
-       if (acts) {
-               struct sw_flow_actions *old_acts;
-
+       if (likely(acts)) {
                old_acts = ovsl_dereference(flow->sf_acts);
                rcu_assign_pointer(flow->sf_acts, acts);
-               ovs_nla_free_flow_actions(old_acts);
+
+               if (unlikely(reply)) {
+                       error = ovs_flow_cmd_fill_info(flow,
+                                                      ovs_header->dp_ifindex,
+                                                      reply, info->snd_portid,
+                                                      info->snd_seq, 0,
+                                                      OVS_FLOW_CMD_NEW);
+                       BUG_ON(error < 0);
+               }
+       } else {
+               /* Could not alloc without acts before locking. */
+               reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex,
+                                               info, OVS_FLOW_CMD_NEW, false);
+               if (unlikely(IS_ERR(reply))) {
+                       error = PTR_ERR(reply);
+                       goto err_unlock_ovs;
+               }
        }
 
-       reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex,
-                                       info, OVS_FLOW_CMD_NEW, false);
        /* Clear stats. */
        if (a[OVS_FLOW_ATTR_CLEAR])
                ovs_flow_stats_clear(flow);
        ovs_unlock();
 
-       if (reply) {
-               if (!IS_ERR(reply))
-                       ovs_notify(&dp_flow_genl_family, reply, info);
-               else
-                       genl_set_err(&dp_flow_genl_family, sock_net(skb->sk), 0,
-                                    0, PTR_ERR(reply));
-       }
+       if (reply)
+               ovs_notify(&dp_flow_genl_family, reply, info);
+       if (old_acts)
+               ovs_nla_free_flow_actions(old_acts);
 
        return 0;
 
 err_unlock_ovs:
        ovs_unlock();
-err_kfree:
+       kfree_skb(reply);
+err_kfree_acts:
        kfree(acts);
 error:
        return error;