Re: [patch 04/13] ppp_generic: fix lockdep warning

[Jarek Poplawski <jarkao2@o2.pl>]

On Mon, May 14, 2007 at 09:28:45AM +0200, Jarek Poplawski wrote:
> On Sun, May 13, 2007 at 11:39:37PM -0700, David Miller wrote:
...
> > For each unique netdev type, use a different locking class.
> > 
> > That will fix this forever, anything else is a situation specific
> > band-aid (but then again isn't that what every lockdep annotation is
> > :-).

Band-aid isn't probably too fair with lockdep. I think, it's very
similar as declaring types of variables for a compiler, it really
can't know until we tell this. And current locks' complexity is
probably beyond possibility of brain analyzing, anyway. (Probably
lockdep could be wiser too - at the cost of memory and speed -
if each lock were treated individually).

> 
> Yes, this is very good idea, and I wonder, why you didn't try
> this yourself (after my "ignore"). I thought a little about
> this, but was afraid of it's wide range. Some things - like
> in vlans - should be removed then, for this to work. I'll try
> to send something like this soon (but I'm not so optimistic
> it will cure all or forever...).

So, because of this next planned patch (I hope not later than
tomorrow), my two last patches for vlan and ppp_generic shouldn't 
be applied - their functionality will be moved to register_netdevice.
(But I think this current: "nesting" patch for ppp_generic does
something different and IMHO could be useful too.)

Jarek P.