[PATCH net-next 7/9] net: bridge: vlan: annotate lockless use of msti

[Nikolay Aleksandrov <razor@blackwall.org>]

Annotate data races around vlan msti field, it can be read lockless.

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 net/bridge/br_mst.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 95e49ec8065e..76a5bf287578 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -123,7 +123,7 @@ int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
 
 	err = 0;
 	list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
-		if (v->brvlan->msti != msti)
+		if (READ_ONCE(v->brvlan->msti) != msti)
 			continue;
 
 		br_mst_vlan_set_state(vg, v, state);
@@ -176,7 +176,7 @@ int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
 	if (err && err != -EOPNOTSUPP)
 		return err;
 
-	mv->msti = msti;
+	WRITE_ONCE(mv->msti, msti);
 
 	list_for_each_entry(p, &mv->br->port_list, list) {
 		vg = nbp_vlan_group(p);
@@ -249,7 +249,9 @@ size_t br_mst_info_size(const struct net_bridge_vlan_group *vg)
 	sz = nla_total_size(0);
 
 	list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
-		if (test_bit(v->brvlan->msti, seen))
+		u16 msti = READ_ONCE(v->brvlan->msti);
+
+		if (test_bit(msti, seen))
 			continue;
 
 		/* IFLA_BRIDGE_MST_ENTRY */
@@ -259,7 +261,7 @@ size_t br_mst_info_size(const struct net_bridge_vlan_group *vg)
 			/* IFLA_BRIDGE_MST_ENTRY_STATE */
 			nla_total_size(sizeof(u8));
 
-		__set_bit(v->brvlan->msti, seen);
+		__set_bit(msti, seen);
 	}
 
 	return sz;
-- 
2.47.3