From 5add2f7288468f35a374620dabf126c13baaea9c Mon Sep 17 00:00:00 2001 From: David Wei Date: Thu, 6 Jun 2024 07:59:08 -0700 Subject: [PATCH] netdevsim: fix backwards compatibility in nsim_get_iflink() 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 Suggested-by: Yu Watanabe Signed-off-by: David Wei Signed-off-by: David S. Miller --- 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 c22897bf5509..017a6102be0a 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -324,7 +324,8 @@ 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; -- 2.25.1