Re: [ovs-dev] [PATCH V3 1/4] dpif-netdev: Flush offload rules upon port deletion

[Eli Britstein]

On 1/4/2021 3:33 PM, Tonghao Zhang wrote:
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On Tue, Dec 29, 2020 at 2:17 AM Eli Britstein <el...@nvidia.com> wrote:
When a port is deleted, flow deletion requests are posted, and the netdev
is removed from offload netdevs map. Following flow deletion handling may
be done after the netdev has already been removed from the offload
netdevs map, so the HW rule is not removed and the data object is not
freed (memory leak). Flush offload rules upon port deletion, and disable
pending handling of offloads to fix it.

Signed-off-by: Eli Britstein <el...@nvidia.com>
Reviewed-by: Gaetan Rivet <gaet...@nvidia.com>
---
  lib/dpif-netdev.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 300861ca5..3f0639fca 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -2281,6 +2281,8 @@ static void
  do_del_port(struct dp_netdev *dp, struct dp_netdev_port *port)
      OVS_REQUIRES(dp->port_mutex)
  {
+    netdev_flow_flush(port->netdev);
+    netdev_uninit_flow_api(port->netdev);
Hi Eli
Why not invoke the netdev_flow_flush in netdev_ports_remove ?
I posted a patch for tc offload, but not accepted yet.
https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatchwork.ozlabs.org%2Fproject%2Fopenvswitch%2Fpatch%2F20200611103635.53367-1-xiangxia.m.yue%40gmail.com%2F&amp;data=04%7C01%7Celibr%40nvidia.com%7C53c2ee7dfde349ce938908d8b0b56f01%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637453640601739470%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=AyQckaIcBfDeGHAJSe43BNAzpCu2q9U3xWbYGzV9hbY%3D&amp;reserved=0

Hi Tonghao,

Thanks for your review.

In dpif-netdev, we should be under port_mutex lock. It is not the case 
in your patch. Also, netdev_uninit_flow_api is called here to make sure 
no more offload requests are handled for this port, even the pending 
ones in the queue. netdev_flow_flush won't do anything if called afterwards.

Thanks,

Eli


      hmap_remove(&dp->ports, &port->node);
      seq_change(dp->port_seq);

--
2.28.0.546.g385c171

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--
Best regards, Tonghao
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