Re: Slab: Remove kmem_cache_t

[Andrew Morton <akpm@osdl.org>]

On Wed, 29 Nov 2006 17:41:18 +1100
Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> > Well, you'd just do
> > 
> > 	extern struct kmem_cache *wozzle;
> > 
> > because you "know" that struct kmem_cache == kmem_cache_t.  The compiler
> > will swallow it all.
> > 
> > Do I need to explain how much that sucks?
> > 
> 
> Well the only code that is doing this is presumably some slab internal
> stuff. And that does "know" that struct kmem_cache == kmem_cache_t.
> Actually, once struct kmem_cache gets moved into slab.h, I would be
> interested to know what remaining forward dependencies are needed at
> all. Christoph?
> 
> To be clear: this won't be some random driver or subsystem code (or
> even anything outside of mm/slab.c, hopefully) that is doing this,
> will it? 

Yes, it will.

Any module which calls kmem_cache_create() needs to save its return value
into some storage.  That storage has type `struct kmem_cache *', or
kmem_cache_t *.

And, btw, in neither case does that kmem_cache_create() caller need to know
what's inside `struct kmem_cache'.

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