[ovs-dev] [PATCH] Skip processing actions when batch is emptied.

[Vishal Deep Ajmera]

Hi,

Do anyone see any issues with the approach below of skipping ovs actions when batch is emptied ?

Warm Regards,
Vishal

-----Original Message-----
From: ovs-dev-bounces at openvswitch.org [mailto:ovs-dev-bounces at openvswitch.org] On Behalf Of Vishal Deep Ajmera
Sent: Wednesday, November 08, 2017 3:14 PM
To: dev at openvswitch.org
Subject: [ovs-dev] [PATCH] Skip processing actions when batch is emptied.

Today in OVS, when errors are encountered during the execution of an action the entire batch of packets may be deleted (for e.g. in processing push_tnl_action, if the port is not found in the port_cache of PMD). The remaining actions continue to be executed even though there are no packets to be processed. It is assumed that the code dealing with each action checks that the batch is not empty before executing. Crashes may occur if the assumption is not met.

The patch makes OVS skip processing of further actions from the action-set once a batch is emptied. Doing so centralizes the check in one place and avoids the possibility of crashes.

Signed-off-by: Vishal Deep Ajmera <vishal.deep.ajmera at ericsson.com>
---
lib/odp-execute.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/odp-execute.c b/lib/odp-execute.c index 3109f39..8697727 100644
--- a/lib/odp-execute.c
+++ b/lib/odp-execute.c
@@ -685,9 +685,12 @@ odp_execute_actions(void *dp, struct dp_packet_batch *batch, bool steal,
                 dp_execute_action(dp, batch, a, may_steal);
-                if (last_action) {
-                    /* We do not need to free the packets. dp_execute_actions()
-                     * has stolen them */
+                if (last_action || (batch->count == 0)) {
+                    /* We do not need to free the packets.
+                     * Either dp_execute_actions() has stolen them
+                     * or the batch is freed due to errors. In either
+                     * case we do not need to execute further actions.
+                     */
                     return;
                 }
             }
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