[PATCH net backport to 5.5 - 5.8.3 v2] net: openvswitch: introduce common code for flushing flows

From: Tonghao Zhang [ Upstream commit 1f3a090b9033f69de380c03db3ea1a1015c850cf ] Backport this commit to 5.5 - 5.8.3. To avoid some issues, for example RCU usage warning and double free, we should flush the flows under ovs_lock. This patch refactors table_instance_destroy and introduces

[PATCH net backport 5.6.14-5.8.3 v1] net: openvswitch: introduce common code for flushing flows

From: Tonghao Zhang [ Upstream commit 77b981c82c1df7c7ad32a046f17f007450b46954 ] Backport this commit to 5.6.14 - 5.8.3. To avoid some issues, for example RCU usage warning and double free, we should flush the flows under ovs_lock. This patch refactors table_instance_destroy and introduces

[PATCH] net: openvswitch: silence suspicious RCU usage warning

From: Tonghao Zhang ovs_flow_tbl_destroy always is called from RCU callback or error path. It is no need to check if rcu_read_lock or lockdep_ovsl_is_held was held. ovs_dp_cmd_fill_info always is called with ovs_mutex, So use the rcu_dereference_ovsl instead of rcu_dereference in