RDMA: Fix netdev tracker in ib_device_set_netdev

If a netdev has already been assigned, ib_device_set_netdev needs to
release the reference on the older netdev but it is mistakenly being
called for the new netdev. Fix it and in the process use netdev_put
to be symmetrical with the netdev_hold.

Fixes: 09f530f ("RDMA: Add netdevice_tracker to ib_device_set_netdev()")
Signed-off-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240710203310.19317-1-dsahern@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/core/device.c

@@ -2184,16 +2184,12 @@ int ib_device_set_netdev(struct ib_device *ib_dev, struct net_device *ndev,
 		return 0;
 	}
 
-	if (old_ndev)
-		netdev_tracker_free(ndev, &pdata->netdev_tracker);
-	if (ndev)
-		netdev_hold(ndev, &pdata->netdev_tracker, GFP_ATOMIC);
 	rcu_assign_pointer(pdata->netdev, ndev);
+	netdev_put(old_ndev, &pdata->netdev_tracker);
+	netdev_hold(ndev, &pdata->netdev_tracker, GFP_ATOMIC);
 	spin_unlock_irqrestore(&pdata->netdev_lock, flags);
 
 	add_ndev_hash(pdata);
-	__dev_put(old_ndev);
-
 	return 0;
 }
 EXPORT_SYMBOL(ib_device_set_netdev);