[PATCH 5.16 0370/1039] net: dsa: fix incorrect function pointer check for MRP ring roles

[Greg Kroah-Hartman]

From: Vladimir Oltean <vladimir.oltean@xxxxxxx>

[ Upstream commit ff91e1b68490b97c18c649b769618815eb945f11 ]

The cross-chip notifier boilerplate code meant to check the presence of
ds->ops->port_mrp_add_ring_role before calling it, but checked
ds->ops->port_mrp_add instead, before calling
ds->ops->port_mrp_add_ring_role.

Therefore, a driver which implements one operation but not the other
would trigger a NULL pointer dereference.

There isn't any such driver in DSA yet, so there is no reason to
backport the change. Issue found through code inspection.

Cc: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
Fixes: c595c4330da0 ("net: dsa: add MRP support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/dsa/switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index bb155a16d4540..80816f7e1f996 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -675,7 +675,7 @@ static int
 dsa_switch_mrp_add_ring_role(struct dsa_switch *ds,
 			     struct dsa_notifier_mrp_ring_role_info *info)
 {
-	if (!ds->ops->port_mrp_add)
+	if (!ds->ops->port_mrp_add_ring_role)
 		return -EOPNOTSUPP;
 
 	if (ds->index == info->sw_index)
@@ -689,7 +689,7 @@ static int
 dsa_switch_mrp_del_ring_role(struct dsa_switch *ds,
 			     struct dsa_notifier_mrp_ring_role_info *info)
 {
-	if (!ds->ops->port_mrp_del)
+	if (!ds->ops->port_mrp_del_ring_role)
 		return -EOPNOTSUPP;
 
 	if (ds->index == info->sw_index)
-- 
2.34.1