netdev - Re: [PATCH net-next v2 2/3] net: openvswitch: refactor flow free function

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Date:   Mon, 24 Aug 2020 21:56:42 +0800
From:   Tonghao Zhang <xiangxia.m.yue@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     Pravin Shelar <pshelar@....org>,
        Cong Wang <xiyou.wangcong@...il.com>,
        ovs dev <dev@...nvswitch.org>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v2 2/3] net: openvswitch: refactor flow free function

On Mon, Aug 24, 2020 at 9:09 PM David Miller <davem@...emloft.net> wrote:
>
> From: xiangxia.m.yue@...il.com
> Date: Mon, 24 Aug 2020 15:36:01 +0800
>
> > To avoid a bug when deleting flows in the future, add
> > BUG_ON in flush flows function.
>
> BUG_ON() is too severe, I think WARN_ON() or similar are sufficient
> because the kernel can try to continue operating if this condition is
> detected.
>
> And you can force the values to zero in such a situation.
Thanks, David
will be changed to:

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 0473758035b5..5378282e1d13 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -492,8 +492,11 @@ void table_instance_flow_flush(struct flow_table *table,
                }
        }

-       BUG_ON(table->count != 0);
-       BUG_ON(table->ufid_count != 0);
+       if (WARN_ON(table->count != 0 ||
+                   table->ufid_count != 0)) {
+               table->count = 0;
+               table->ufid_count = 0
+       }
 }

> Thank you.



-- 
Best regards, Tonghao