net-loopback: set lo dev initial state to UP

Traditionally loopback devices come up with initial state as DOWN for
any new network-namespace. This would mean that anyone needing this
device would have to bring this UP by issuing something like 'ip link
set lo up'. This can be avoided if the initial state is set as UP.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Jian Yang <jianyang@google.com>
Link: https://lore.kernel.org/r/20210201233445.2044327-1-jianyang.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index a1c77cc0041657de79b562c84408acabf9e8b99b..24487ec17f8b125ab260484f4f7ea83cdadad48d 100644 (file)
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -219,6 +219,12 @@ static __net_init int loopback_net_init(struct net *net)
 
        BUG_ON(dev->ifindex != LOOPBACK_IFINDEX);
        net->loopback_dev = dev;
+
+       /* bring loopback device UP */
+       rtnl_lock();
+       dev_open(dev, NULL);
+       rtnl_unlock();
+
        return 0;
 
 out_free_netdev: