On Thu, Jul 10, 2014 at 1:16 AM, Andy Zhou <az...@nicira.com> wrote:
> skb_clone() NULL check is implemented in do_output(), as past of the
> common (fast) path. Refactoring so that NULL check is done in the
> slow path, immediately after skb_clone() is called.
>
> Besides optimization, this change also improves code readability by
> making the skb_clone() NULL check consistent within OVS datapath
> module.
>
> Signed-off-by: Andy Zhou <az...@nicira.com>
> ---
> datapath/actions.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/datapath/actions.c b/datapath/actions.c
> index daa7b43..6eb83b8 100644
> --- a/datapath/actions.c
> +++ b/datapath/actions.c
> @@ -490,9 +490,6 @@ static int do_output(struct datapath *dp, struct sk_buff
> *skb, int out_port)
> {
> struct vport *vport;
>
> - if (unlikely(!skb))
> - return -ENOMEM;
> -
There is no check for do_output() return, Therefore we can make it return void.
> vport = ovs_vport_rcu(dp, out_port);
> if (unlikely(!vport)) {
> kfree_skb(skb);
> @@ -693,7 +690,12 @@ static int do_execute_actions(struct datapath *dp,
> struct sk_buff *skb,
> int err = 0;
>
> if (prev_port != -1) {
This can be marked as unlikely
> - do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
> + struct sk_buff *out_skb = skb_clone(skb, GFP_ATOMIC);
> +
> + if (!out_skb)
> + return -ENOMEM;
> +
This changes behavior, we can just skip do_output if it skb_clone() fails.
> + do_output(dp, out_skb, prev_port);
> prev_port = -1;
> }
>
otherwise looks good.
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