Commit bd380811 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

dev: support deferring device flag change notifications 



Split dev_change_flags() into two functions: __dev_change_flags() to
perform the actual changes and __dev_notify_flags() to invoke netdevice
notifiers. This will be used by rtnl_link to defer netlink notifications
until the device has been fully configured.

This changes ordering of some operations, in particular:

- netlink notifications are sent after all changes have been performed.
  As a side effect this surpresses one unnecessary netlink message when
  the IFF_UP and other flags are changed simultaneously.

- The NETDEV_UP/NETDEV_DOWN and NETDEV_CHANGE notifiers are invoked
  after all changes have been performed. Their relative is unchanged.

- net_dmaengine_put() is invoked before the NETDEV_DOWN notifier instead
  of afterwards. This should not make any difference since both RX and TX
  are already shut down at this point.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2835763

include/linux/netdevice.h

+2 −0
Original line number Diff line number Diff line
@@ -1587,7 +1587,9 @@ extern int dev_valid_name(const char *name); 
extern int		dev_ioctl(struct net *net, unsigned int cmd, void __user *);

extern int		dev_ethtool(struct net *net, struct ifreq *);

extern unsigned		dev_get_flags(const struct net_device *);

extern int		__dev_change_flags(struct net_device *, unsigned int flags);

extern int		dev_change_flags(struct net_device *, unsigned);

extern void		__dev_notify_flags(struct net_device *, unsigned int old_flags);

extern int		dev_change_name(struct net_device *, const char *);

extern int		dev_set_alias(struct net_device *, const char *, size_t);

extern int		dev_change_net_namespace(struct net_device *,

net/core/dev.c

+104 −59
Original line number Diff line number Diff line
@@ -1113,32 +1113,13 @@ void dev_load(struct net *net, const char *name) 
}

EXPORT_SYMBOL(dev_load);



/**

 *	dev_open	- prepare an interface for use.

 *	@dev:	device to open

 *

 *	Takes a device from down to up state. The device's private open

 *	function is invoked and then the multicast lists are loaded. Finally

 *	the device is moved into the up state and a %NETDEV_UP message is

 *	sent to the netdev notifier chain.

 *

 *	Calling this function on an active interface is a nop. On a failure

 *	a negative errno code is returned.

 */

int dev_open(struct net_device *dev)

static int __dev_open(struct net_device *dev)

{

	const struct net_device_ops *ops = dev->netdev_ops;

	int ret;



	ASSERT_RTNL();



	/*

	 *	Is it already up?

	 */



	if (dev->flags & IFF_UP)

		return 0;



	/*

	 *	Is it even present?

	 */
@@ -1187,36 +1168,57 @@ int dev_open(struct net_device *dev) 
		 *	Wakeup transmit queue engine

		 */

		dev_activate(dev);

	}



	return ret;

}



/**

 *	dev_open	- prepare an interface for use.

 *	@dev:	device to open

 *

 *	Takes a device from down to up state. The device's private open

 *	function is invoked and then the multicast lists are loaded. Finally

 *	the device is moved into the up state and a %NETDEV_UP message is

 *	sent to the netdev notifier chain.

 *

 *	Calling this function on an active interface is a nop. On a failure

 *	a negative errno code is returned.

 */

int dev_open(struct net_device *dev)

{

	int ret;



	/*

	 *	Is it already up?

	 */

	if (dev->flags & IFF_UP)

		return 0;



	/*

	 *	Open device

	 */

	ret = __dev_open(dev);

	if (ret < 0)

		return ret;



	/*

	 *	... and announce new interface.

	 */

	rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);

	call_netdevice_notifiers(NETDEV_UP, dev);

	}



	return ret;

}

EXPORT_SYMBOL(dev_open);



/**

 *	dev_close - shutdown an interface.

 *	@dev: device to shutdown

 *

 *	This function moves an active device into down state. A

 *	%NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device

 *	is then deactivated and finally a %NETDEV_DOWN is sent to the notifier

 *	chain.

 */

int dev_close(struct net_device *dev)

static int __dev_close(struct net_device *dev)

{

	const struct net_device_ops *ops = dev->netdev_ops;

	ASSERT_RTNL();



	ASSERT_RTNL();

	might_sleep();



	if (!(dev->flags & IFF_UP))

		return 0;



	/*

	 *	Tell people we are going down, so that they can

	 *	prepare to death, when device is still operating.
@@ -1252,14 +1254,34 @@ int dev_close(struct net_device *dev) 
	dev->flags &= ~IFF_UP;



	/*

	 * Tell people we are down

	 *	Shutdown NET_DMA

	 */

	call_netdevice_notifiers(NETDEV_DOWN, dev);

	net_dmaengine_put();



	return 0;

}



/**

 *	dev_close - shutdown an interface.

 *	@dev: device to shutdown

 *

 *	This function moves an active device into down state. A

 *	%NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device

 *	is then deactivated and finally a %NETDEV_DOWN is sent to the notifier

 *	chain.

 */

int dev_close(struct net_device *dev)

{

	if (!(dev->flags & IFF_UP))

		return 0;



	__dev_close(dev);



	/*

	 *	Shutdown NET_DMA

	 * Tell people we are down

	 */

	net_dmaengine_put();

	rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);

	call_netdevice_notifiers(NETDEV_DOWN, dev);



	return 0;

}
@@ -4299,18 +4321,10 @@ unsigned dev_get_flags(const struct net_device *dev) 
}

EXPORT_SYMBOL(dev_get_flags);



/**

 *	dev_change_flags - change device settings

 *	@dev: device

 *	@flags: device state flags

 *

 *	Change settings on device based state flags. The flags are

 *	in the userspace exported format.

 */

int dev_change_flags(struct net_device *dev, unsigned flags)

int __dev_change_flags(struct net_device *dev, unsigned int flags)

{

	int ret, changes;

	int old_flags = dev->flags;

	int ret;



	ASSERT_RTNL();
@@ -4341,17 +4355,12 @@ int dev_change_flags(struct net_device *dev, unsigned flags) 


	ret = 0;

	if ((old_flags ^ flags) & IFF_UP) {	/* Bit is different  ? */

		ret = ((old_flags & IFF_UP) ? dev_close : dev_open)(dev);

		ret = ((old_flags & IFF_UP) ? __dev_close : __dev_open)(dev);



		if (!ret)

			dev_set_rx_mode(dev);

	}



	if (dev->flags & IFF_UP &&

	    ((old_flags ^ dev->flags) & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI |

					  IFF_VOLATILE)))

		call_netdevice_notifiers(NETDEV_CHANGE, dev);



	if ((flags ^ dev->gflags) & IFF_PROMISC) {

		int inc = (flags & IFF_PROMISC) ? 1 : -1;
@@ -4370,11 +4379,47 @@ int dev_change_flags(struct net_device *dev, unsigned flags) 
		dev_set_allmulti(dev, inc);

	}



	/* Exclude state transition flags, already notified */

	changes = (old_flags ^ dev->flags) & ~(IFF_UP | IFF_RUNNING);

	return ret;

}



void __dev_notify_flags(struct net_device *dev, unsigned int old_flags)

{

	unsigned int changes = dev->flags ^ old_flags;



	if (changes & IFF_UP) {

		if (dev->flags & IFF_UP)

			call_netdevice_notifiers(NETDEV_UP, dev);

		else

			call_netdevice_notifiers(NETDEV_DOWN, dev);

	}



	if (dev->flags & IFF_UP &&

	    (changes & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI | IFF_VOLATILE)))

		call_netdevice_notifiers(NETDEV_CHANGE, dev);

}



/**

 *	dev_change_flags - change device settings

 *	@dev: device

 *	@flags: device state flags

 *

 *	Change settings on device based state flags. The flags are

 *	in the userspace exported format.

 */

int dev_change_flags(struct net_device *dev, unsigned flags)

{

	int ret, changes;

	int old_flags = dev->flags;



	ret = __dev_change_flags(dev, flags);

	if (ret < 0)

		return ret;



	changes = old_flags ^ dev->flags;

	if (changes)

		rtmsg_ifinfo(RTM_NEWLINK, dev, changes);



	__dev_notify_flags(dev, old_flags);

	return ret;

}

EXPORT_SYMBOL(dev_change_flags);

net/core/rtnetlink.c

+0 −2
Original line number Diff line number Diff line
@@ -1427,8 +1427,6 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi 
	switch (event) {

	case NETDEV_UP:

	case NETDEV_DOWN:

		rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);

		break;

	case NETDEV_PRE_UP:

	case NETDEV_POST_INIT:

	case NETDEV_REGISTER:

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