From: Andy Zhou <az...@nicira.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 <az...@nicira.com>
Acked-by: Pravin B Shelar <pshe...@nicira.com>
---
datapath/actions.c | 36 ++++++++++++++++--------------------
1 files changed, 16 insertions(+), 20 deletions(-)
diff --git a/datapath/actions.c b/datapath/actions.c
index a688f19..66660d9 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -469,27 +469,23 @@ static int sample(struct datapath *dp, struct sk_buff
*skb,
rem = nla_len(acts_list);
a = nla_data(acts_list);
- /* 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. */
- 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);
- }
+ /* Actions list is empty, do nothing */
+ if (unlikely(!rem))
+ return 0;
+
+ /* 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(nla_type(a) == OVS_ACTION_ATTR_USERSPACE &&
+ last_action(a, rem)))
+ return output_userspace(dp, skb, a);
+
+ skb = skb_clone(skb, GFP_ATOMIC);
+ if (!skb)
+ /* Skip the sample action when out of memory. */
+ return 0;
- /* 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);
}
--
1.7.1
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