6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Wei <dw@xxxxxxxxxxx>
[ Upstream commit 5add2f7288468f35a374620dabf126c13baaea9c ]
The default ndo_get_iflink() implementation returns the current ifindex
of the netdev. But the overridden nsim_get_iflink() returns 0 if the
current nsim is not linked, breaking backwards compatibility for
userspace that depend on this behaviour.
Fix the problem by returning the current ifindex if not linked to a
peer.
Fixes: 8debcf5832c3 ("netdevsim: add ndo_get_iflink() implementation")
Reported-by: Yu Watanabe <watanabe.yu@xxxxxxxxx>
Suggested-by: Yu Watanabe <watanabe.yu@xxxxxxxxx>
Signed-off-by: David Wei <dw@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/netdevsim/netdev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 8330bc0bcb7e5..d405809030aab 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -292,7 +292,8 @@ static int nsim_get_iflink(const struct net_device *dev)
rcu_read_lock();
peer = rcu_dereference(nsim->peer);
- iflink = peer ? READ_ONCE(peer->netdev->ifindex) : 0;
+ iflink = peer ? READ_ONCE(peer->netdev->ifindex) :
+ READ_ONCE(dev->ifindex);
rcu_read_unlock();
return iflink;
--
2.43.0
