netdev - Re: [net-next] openvswitch: Simplify do_execute

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Date:   Fri, 27 Jan 2017 13:25:52 -0800
From:   Andy Zhou <azhou@....org>
To:     Pravin Shelar <pshelar@....org>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [net-next] openvswitch: Simplify do_execute_actions().

On Fri, Jan 27, 2017 at 12:42 PM, Pravin Shelar <pshelar@....org> wrote:
> On Wed, Jan 25, 2017 at 9:24 PM, Andy Zhou <azhou@....org> wrote:
>> do_execute_actions() implements a worthwhile optimization: in case
>> an output action is the last action in an action list, skb_clone()
>> can be avoided by outputing the current skb. However, the
>> implementation is more complicated than necessary.  This patch
>> simplify this logic.
>>
>> Signed-off-by: Andy Zhou <azhou@....org>
>> ---
>>  net/openvswitch/actions.c | 40 +++++++++++++++++++---------------------
>>  1 file changed, 19 insertions(+), 21 deletions(-)
>>
>> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
>> index 514f7bc..3866608 100644
>> --- a/net/openvswitch/actions.c
>> +++ b/net/openvswitch/actions.c
>> @@ -830,6 +830,9 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
>>  {
>>         struct vport *vport = ovs_vport_rcu(dp, out_port);
>>
>> +       if (unlikely(!skb))
>> +               return;
>> +
> Patch looks good to me. But I wanted to know if you considered moving
> this check to do_execute_actions() in case skb-clone is done? This way
> we can avoid this unlikely check from likely case :)
>
Good point.  O.K. I will repost a version without this check.  Thanks
for the review and comment.