[PATCH 3/4] datapath.c: Use built-in RCU list checking

[PATCH 3/4] datapath.c: Use built-in RCU list checking

[madhuparnabhowmik10]

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

hlist_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
by default.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
 net/openvswitch/datapath.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 1047e8043084..2b7a348ad167 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -179,7 +179,8 @@ struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no)
 	struct hlist_head *head;
 
 	head = vport_hash_bucket(dp, port_no);
-	hlist_for_each_entry_rcu(vport, head, dp_hash_node) {
+	hlist_for_each_entry_rcu(vport, head, dp_hash_node,
+				lockdep_ovsl_is_held()) {
 		if (vport->port_no == port_no)
 			return vport;
 	}
@@ -2045,7 +2046,8 @@ static unsigned int ovs_get_max_headroom(struct datapath *dp)
 	int i;
 
 	for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
-		hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node) {
+		hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node,
+					lockdep_ovsl_is_held()) {
 			dev = vport->dev;
 			dev_headroom = netdev_get_fwd_headroom(dev);
 			if (dev_headroom > max_headroom)
@@ -2064,7 +2066,8 @@ static void ovs_update_headroom(struct datapath *dp, unsigned int new_headroom)
 
 	dp->max_headroom = new_headroom;
 	for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++)
-		hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node)
+		hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node,
+					lockdep_ovsl_is_held())
 			netdev_set_rx_headroom(vport->dev, new_headroom);
 }
 
-- 
2.17.1

Re: [PATCH 3/4] datapath.c: Use built-in RCU list checking

[David Miller]

From: madhuparnabhowmik10@gmail.com
Date: Wed, 19 Feb 2020 01:28:02 +0530

> From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> 
> hlist_for_each_entry_rcu() has built-in RCU and lock checking.
> 
> Pass cond argument to list_for_each_entry_rcu() to silence
> false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
> by default.
> 
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

Applied.