Subject: Re: [PATCH] openvswitch: using kfree_rcu() to simplify the code

From: "Paul E. McKenney" <[email-masked]>
Date: Thu, 20 Sep 2012 10:47:36 -0700

On Mon, Aug 27, 2012 at 12:20:45PM +0800, Wei Yongjun wrote:
> From: Wei Yongjun <[email-masked]>
> 
> The callback function of call_rcu() just calls a kfree(), so we
> can use kfree_rcu() instead of call_rcu() + callback function.
> 
> spatch with a semantic match is used to found this problem.
> (http://coccinelle.lip6.fr/)
> 
> Signed-off-by: Wei Yongjun <[email-masked]>

Reviewed-by: Paul E. McKenney <[email-masked]>

> ---
>  net/openvswitch/flow.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
> index b7f38b1..c7bf2f2 100644
> --- a/net/openvswitch/flow.c
> +++ b/net/openvswitch/flow.c
> @@ -427,19 +427,11 @@ void ovs_flow_deferred_free(struct sw_flow *flow)
>  	call_rcu(&flow->rcu, rcu_free_flow_callback);
>  }
> 
> -/* RCU callback used by ovs_flow_deferred_free_acts. */
> -static void rcu_free_acts_callback(struct rcu_head *rcu)
> -{
> -	struct sw_flow_actions *sf_acts = container_of(rcu,
> -			struct sw_flow_actions, rcu);
> -	kfree(sf_acts);
> -}
> -
>  /* Schedules 'sf_acts' to be freed after the next RCU grace period.
>   * The caller must hold rcu_read_lock for this to be sensible. */
>  void ovs_flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
>  {
> -	call_rcu(&sf_acts->rcu, rcu_free_acts_callback);
> +	kfree_rcu(sf_acts, rcu);
>  }
> 
>  static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
> 
> --
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