Re: [PATCH] net: openvswitch: introduce common code for flushing flows

On Mon, Aug 10, 2020 at 6:14 PM [off-list ref] wrote:

From: Tonghao Zhang <redacted>

To avoid some issues, for example RCU usage warning, we should
flush the flows under ovs_lock. This patch refactors
table_instance_destroy and introduces table_instance_flow_flush
which can be invoked by __dp_destroy or ovs_flow_tbl_flush.

Signed-off-by: Tonghao Zhang <redacted>

Please add a Fixes tag here, I think it is probably your memory leak fix
which introduced this issue. And a Reported-by, to give credits to bug
reporters.

Plus one minor issue below:

-static void table_instance_destroy(struct flow_table *table,
-                                  struct table_instance *ti,
-                                  struct table_instance *ufid_ti,
-                                  bool deferred)
+/* Must be called with OVS mutex held. */
+void table_instance_flow_flush(struct flow_table *table,
+                              struct table_instance *ti,
+                              struct table_instance *ufid_ti)
 {
        int i;

-       if (!ti)
-               return;
-
-       BUG_ON(!ufid_ti);
        if (ti->keep_flows)
-               goto skip_flows;
+               return;

        for (i = 0; i < ti->n_buckets; i++) {
-               struct sw_flow *flow;
                struct hlist_head *head = &ti->buckets[i];
                struct hlist_node *n;
+               struct sw_flow *flow;

This is at most a coding style change, please do not mix
coding style changes in bug fixes. You can always push coding
style changes separately when net-next is open.

Thanks.