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Date: Thu, 11 Sep 2014 16:28:13 -0700 From: Pravin B Shelar <pshelar@...ira.com> To: davem@...emloft.net Cc: netdev@...r.kernel.org, Andy Zhou <azhou@...ira.com>, Pravin B Shelar <pshelar@...ira.com> Subject: [PATCH net-next v2 3/4] openvswitch: simplify sample action implementation From: Andy Zhou <azhou@...ira.com> The current sample() function implementation is more complicated than necessary in handling single user space action optimization and skb reference counting. There is no functional changes. Signed-off-by: Andy Zhou <azhou@...ira.com> Signed-off-by: Pravin B Shelar <pshelar@...ira.com> --- net/openvswitch/actions.c | 43 ++++++++++++++++++------------------------- 1 file changed, 18 insertions(+), 25 deletions(-) diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 39c722f..fda7ef3 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -449,7 +449,6 @@ static int sample(struct datapath *dp, struct sk_buff *skb, { const struct nlattr *acts_list = NULL; const struct nlattr *a; - struct sk_buff *sample_skb; int rem; for (a = nla_data(attr), rem = nla_len(attr); rem > 0; @@ -467,33 +466,27 @@ static int sample(struct datapath *dp, struct sk_buff *skb, } rem = nla_len(acts_list); - a = nla_data(acts_list); + /* Actions list is empty, do nothing */ + if (unlikely(!rem)) + return 0; - /* Actions list is either empty or only contains a single user-space - * action, the latter being a special case as it is the only known - * usage of the sample action. - * In these special cases don't clone the skb as there are no - * side-effects in the nested actions. - * Otherwise, clone in case the nested actions have side effects. + a = nla_data(acts_list); + /* The only known usage of sample action is having a single user-space + * action. Treat this usage as a special case. + * The output_userspace() should clone the skb to be sent to the + * user space. This skb will be consumed by its caller. */ - if (likely(rem == 0 || (nla_type(a) == OVS_ACTION_ATTR_USERSPACE && - last_action(a, rem)))) { - sample_skb = skb; - skb_get(skb); - } else { - sample_skb = skb_clone(skb, GFP_ATOMIC); - if (!sample_skb) /* Skip sample action when out of memory. */ - return 0; - } + if (likely(nla_type(a) == OVS_ACTION_ATTR_USERSPACE && + last_action(a, rem))) + return output_userspace(dp, skb, a); - /* Note that do_execute_actions() never consumes skb. - * In the case where skb has been cloned above it is the clone that - * is consumed. Otherwise the skb_get(skb) call prevents - * consumption by do_execute_actions(). Thus, it is safe to simply - * return the error code and let the caller (also - * do_execute_actions()) free skb on error. - */ - return do_execute_actions(dp, sample_skb, a, rem); + skb = skb_clone(skb, GFP_ATOMIC); + if (!skb) + /* Skip the sample action when out of memory. */ + return 0; + + /* do_execute_actions() will consume the cloned skb. */ + return do_execute_actions(dp, skb, a, rem); } static int execute_set_action(struct sk_buff *skb, -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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