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dev: support deferring device flag change notifications

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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: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2010-02-26 06:34:53 +00:00 • committed by David S. Miller
commit bd38081160
3 changed files with 109 additions and 64 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/linux/netdevice.h
View file

@ -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 *,

161
net/core/dev.c
View file

@ -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();
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.
@ -1251,11 +1253,6 @@ int dev_close(struct net_device *dev)
dev->flags &= ~IFF_UP;
/*
* Tell people we are down
*/
call_netdevice_notifiers(NETDEV_DOWN, dev);
/*
* Shutdown NET_DMA
*/
@ -1263,6 +1260,31 @@ int dev_close(struct net_device *dev)
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);
/*
* Tell people we are down
*/
rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
call_netdevice_notifiers(NETDEV_DOWN, dev);
return 0;
}
EXPORT_SYMBOL(dev_close);
@ -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);

2
net/core/rtnetlink.c
View file

@ -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: