diff mbox series

[net-next,v2,2/3] net: openvswitch: refactor flow free function

Message ID 20200824073602.70812-3-xiangxia.m.yue@gmail.com
State Changes Requested
Delegated to: David Miller
Headers show
Series net: openvswitch: improve codes | expand

Commit Message

Tonghao Zhang Aug. 24, 2020, 7:36 a.m. UTC 
From: Tonghao Zhang <xiangxia.m.yue@gmail.com>

Decrease table->count and ufid_count unconditionally,
because we only don't use count or ufid_count to count
when flushing the flows. To simplify the codes, we
remove the "count" argument of table_instance_flow_free.

To avoid a bug when deleting flows in the future, add
BUG_ON in flush flows function.

Cc: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
v2:
add more details why refactor this function.
---
 net/openvswitch/flow_table.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

Comments

David Miller Aug. 24, 2020, 1:09 p.m. UTC | #1 
From: xiangxia.m.yue@gmail.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.

Thank you.
Tonghao Zhang Aug. 24, 2020, 1:56 p.m. UTC | #2 
On Mon, Aug 24, 2020 at 9:09 PM David Miller <davem@davemloft.net> wrote:
>
> From: xiangxia.m.yue@gmail.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.
diff mbox series

Patch

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 4b7ab62d0e1a..f8a21dd80e72 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -459,18 +459,14 @@  static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
 static void table_instance_flow_free(struct flow_table *table,
 				     struct table_instance *ti,
 				     struct table_instance *ufid_ti,
-				     struct sw_flow *flow,
-				     bool count)
+				     struct sw_flow *flow)
 {
 	hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
-	if (count)
-		table->count--;
+	table->count--;
 
 	if (ovs_identifier_is_ufid(&flow->id)) {
 		hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
-
-		if (count)
-			table->ufid_count--;
+		table->ufid_count--;
 	}
 
 	flow_mask_remove(table, flow->mask);
@@ -495,10 +491,13 @@  void table_instance_flow_flush(struct flow_table *table,
 					  flow_table.node[ti->node_ver]) {
 
 			table_instance_flow_free(table, ti, ufid_ti,
-						 flow, false);
+						 flow);
 			ovs_flow_free(flow, true);
 		}
 	}
+
+	BUG_ON(table->count != 0);
+	BUG_ON(table->ufid_count != 0);
 }
 
 static void table_instance_destroy(struct table_instance *ti,
@@ -635,8 +634,6 @@  int ovs_flow_tbl_flush(struct flow_table *flow_table)
 	rcu_assign_pointer(flow_table->ti, new_ti);
 	rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti);
 	flow_table->last_rehash = jiffies;
-	flow_table->count = 0;
-	flow_table->ufid_count = 0;
 
 	table_instance_flow_flush(flow_table, old_ti, old_ufid_ti);
 	table_instance_destroy(old_ti, old_ufid_ti);
@@ -954,7 +951,7 @@  void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
 	struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);
 
 	BUG_ON(table->count == 0);
-	table_instance_flow_free(table, ti, ufid_ti, flow, true);
+	table_instance_flow_free(table, ti, ufid_ti, flow);
 }
 
 static struct sw_flow_mask *mask_alloc(void)