Commit 728c0208 authored Jan 16, 2015 by Florian Fainelli Committed by David S. Miller Jan 19, 2015

net: ipv4: handle DSA enabled master network devices



The logic to configure a network interface for kernel IP
auto-configuration is very simplistic, and does not handle the case
where a device is stacked onto another such as with DSA. This causes the
kernel not to open and configure the master network device in a DSA
switch tree, and therefore slave network devices using this master
network devices as conduit device cannot be open.

This restriction comes from a check in net/dsa/slave.c, which is
basically checking the master netdev flags for IFF_UP and returns
-ENETDOWN if it is not the case.

Automatically bringing-up DSA master network devices allows DSA slave
network devices to be used as valid interfaces for e.g: NFS root booting
by allowing kernel IP autoconfiguration to succeed on these interfaces.

On the reverse path, make sure we do not attempt to close a DSA-enabled
device as this would implicitely prevent the slave DSA network device
from operating.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5bdc7380

net/ipv4/ipconfig.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -209,9 +209,9 @@ static int __init ic_open_devs(void)
		last = &ic_first_dev;
		rtnl_lock();

		/* bring loopback device up first */
		/* bring loopback and DSA master network devices up first */
		for_each_netdev(&init_net, dev) {
		if (!(dev->flags & IFF_LOOPBACK))
		if (!(dev->flags & IFF_LOOPBACK) && !netdev_uses_dsa(dev))
		continue;
		if (dev_change_flags(dev, dev->flags \| IFF_UP) < 0)
		pr_err("IP-Config: Failed to open %s\n", dev->name);
		@@ -306,7 +306,7 @@ static void __init ic_close_devs(void)
		while ((d = next)) {
		next = d->next;
		dev = d->dev;
		if (dev != ic_dev) {
		if (dev != ic_dev && !netdev_uses_dsa(dev)) {
		DBG(("IP-Config: Downing %s\n", dev->name));
		dev_change_flags(dev, d->flags);
		}

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