Re: Bug#251215: kernel-image-2.6.6-1-k7: pppd locks up, cannot be killed, during ppp shutdown

[Stephen Hemminger <shemminger@xxxxxxxx>]

On Sat, 29 May 2004 12:48:33 -0700
"David S. Miller" <davem@xxxxxxxxxx> wrote:

> On Sat, 29 May 2004 15:17:36 +1000
> Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> 
> > Why do we need to call free_netdev after unregistering the netdev
> > from the drivers at all? What's wrong with calling it from run_todo
> > itself?
> 
> Because the driver is the only agent which knows when it is safe
> to free up the structure.  It may still have some attached memory
> to free, for example, ala:
> 
>       unregister_netdev(dev);
>       kfree(dev->priv);
>       free_netdev(dev);
> 
> This is common, for example in drivers/net/tg3.c:tg3_remove_one() we
> have:
> 
>               struct tg3 *tp = netdev_priv(dev);
> 
>               unregister_netdev(dev);
>               iounmap((void *)tp->regs);
>               free_netdev(dev);
> 
Also, for those device that don't want to do anything in between:
        dev->destructor = free_netdev;

Will end up calling free_netdev in the run_todo processing. This
can be very handy when unregister needs to happen in some context
already called with RTNL.