[ovs-dev] [PATCH v5 5/9] datapath: Minimize ovs_flow_cmd_del critical section.

[Pravin Shelar]

On Tue, Mar 25, 2014 at 2:35 PM, Jarno Rajahalme <jrajahalme at nicira.com> wrote:
> ovs_flow_cmd_del() now allocates reply (if needed) after the flow has
> already been removed from the flow table.  If the reply allocation
> fails, a netlink error is signaled with netlink_set_err(), as is
> already done in ovs_flow_cmd_new_or_set() in the similar situation.
>
> Signed-off-by: Jarno Rajahalme <jrajahalme at nicira.com>
LGTM
Acked-by: Pravin B Shelar <pshelar at nicira.com>

> ---
>  datapath/datapath.c |   39 ++++++++++++++++-----------------------
>  1 file changed, 16 insertions(+), 23 deletions(-)
>
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index 01913f6..a13208c 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -997,50 +997,43 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct genl_info *info)
>         struct sw_flow_match match;
>         int err;
>
> +       if (a[OVS_FLOW_ATTR_KEY]) {
> +               ovs_match_init(&match, &key, NULL);
> +               err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL);
> +               if (err)
> +                       return err;
> +       }
> +
>         ovs_lock();
>         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
>         if (!dp) {
>                 err = -ENODEV;
>                 goto unlock;
>         }
> -
>         if (!a[OVS_FLOW_ATTR_KEY]) {
>                 err = ovs_flow_tbl_flush(&dp->table);
>                 goto unlock;
>         }
> -
> -       ovs_match_init(&match, &key, NULL);
> -       err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL);
> -       if (err)
> -               goto unlock;
> -
>         flow = ovs_flow_tbl_lookup(&dp->table, &key);
>         if (!flow || !ovs_flow_cmp_unmasked_key(flow, &match)) {
>                 err = -ENOENT;
>                 goto unlock;
>         }
> -
> -       reply = ovs_flow_cmd_alloc_info(flow, info, false);
> -       if (IS_ERR(reply)) {
> -               err = PTR_ERR(reply);
> -               goto unlock;
> -       }
> -
>         ovs_flow_tbl_remove(&dp->table, flow);
> +       ovs_unlock();
>
> +       reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex,
> +                                       info, OVS_FLOW_CMD_DEL, false);
>         if (reply) {
> -               err = ovs_flow_cmd_fill_info(flow, ovs_header->dp_ifindex,
> -                                            reply, info->snd_portid,
> -                                            info->snd_seq, 0,
> -                                            OVS_FLOW_CMD_DEL);
> -               BUG_ON(err < 0);
> +               if (!IS_ERR(reply))
> +                       ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
> +               else
> +                       netlink_set_err(sock_net(skb->sk)->genl_sock, 0,
> +                                       ovs_dp_flow_multicast_group.id,
> +                                       PTR_ERR(reply));
>         }
>
>         ovs_flow_free(flow, true);
> -       ovs_unlock();
> -
> -       if (reply)
> -               ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
>         return 0;
>  unlock:
>         ovs_unlock();
> --
> 1.7.10.4
>
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