xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rtnetlink: wait for unregistering devices in rtnl_link_unregister()

Browse Source 
From: Cong Wang <cwang@twopensource.com>

commit 50624c934d (net: Delay default_device_exit_batch until no
devices are unregistering) introduced rtnl_lock_unregistering() for
default_device_exit_batch(). Same race could happen we when rmmod a driver
which calls rtnl_link_unregister() as we call dev->destructor without rtnl
lock.

For long term, I think we should clean up the mess of netdev_run_todo()
and net namespce exit code.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Cong Wang
2014-05-12 15:11:20 -07:00
committed by David S. Miller
parent e84d2f8d2a
commit 200b916f35
4 changed files with 39 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
net/core/rtnetlink.c
View File

@@ -353,15 +353,46 @@ void __rtnl_link_unregister(struct rtnl_link_ops *ops)
}
EXPORT_SYMBOL_GPL(__rtnl_link_unregister);
/* Return with the rtnl_lock held when there are no network
* devices unregistering in any network namespace.
*/
static void rtnl_lock_unregistering_all(void)
{
struct net *net;
bool unregistering;
DEFINE_WAIT(wait);
for (;;) {
prepare_to_wait(&netdev_unregistering_wq, &wait,
TASK_UNINTERRUPTIBLE);
unregistering = false;
rtnl_lock();
for_each_net(net) {
if (net->dev_unreg_count > 0) {
unregistering = true;
break;
}
}
if (!unregistering)
break;
__rtnl_unlock();
schedule();
}
finish_wait(&netdev_unregistering_wq, &wait);
}
/**
* rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
* @ops: struct rtnl_link_ops * to unregister
*/
void rtnl_link_unregister(struct rtnl_link_ops *ops)
{
rtnl_lock();
/* Close the race with cleanup_net() */
mutex_lock(&net_mutex);
rtnl_lock_unregistering_all();
__rtnl_link_unregister(ops);
rtnl_unlock();
mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(rtnl_link_unregister);