netpoll: prevent netpoll setup on slave devices
In commit 8d8fc29d02a33e4bd5f4fa47823c1fd386346093
(netpoll: disable netpoll when enslave a device), we automatically
disable netpoll when the underlying device is being enslaved,
we also need to prevent people from setuping netpoll on
devices that are already enslaved.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 2d7d6d4..42ea4b0 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -792,6 +792,12 @@
return -ENODEV;
}
+ if (ndev->master) {
+ printk(KERN_ERR "%s: %s is a slave device, aborting.\n",
+ np->name, np->dev_name);
+ return -EBUSY;
+ }
+
if (!netif_running(ndev)) {
unsigned long atmost, atleast;