Re: race in net/ipv4/ipip.c ?

["David S. Miller" <davem@xxxxxxxxxxxxx>]

On Wed, 12 Jan 2005 14:21:26 +0100
Thomas Graf <tgraf@xxxxxxx> wrote:

> * YOSHIFUJI Hideaki / ?$B5HF#1QL@ 
> <20050112.220816.56650893.yoshfuji@xxxxxxxxxxxxxx> 2005-01-12 22:08
> > How about adding multiple tunnels (with same ipip_bucket(t))
> > concurrently? :-)
> > 
> 
> * Lennert Buytenhek <20050112130940.GA12547@xxxxxxxxxxxxxxxxx> 2005-01-12 
> 14:09
> > What if you add two tunnels at the same time?  (Or is that perhaps
> > synchronised on a higher level?)
> 
> Not possible, protected via rtnl semaphore acquired in default
> handler of dev_ioctl.

Yeah.  Alexey does this trick everywhere, when we have the RTNL semaphore
held we only need to lock for the actual linkage operation that adds the
new object to the tree.