[patch v2] LMB: Add basic spin locking to lmb

[David Miller]

From: Geoff Levand <geoffrey.levand at am.sony.com>
Date: Mon, 19 May 2008 17:55:45 -0700

> Add a spinlock to struct lmb to enforce concurrency in
> lmb_add(), lmb_remove(), lmb_analyze(), lmb_find(), and
> lmb_dump_all().
> 
> This locking is needed for SMP systems that access the lmb structure
> during hot memory add and remove operations after secondary cpus
> have been started.
> 
> Signed-off-by: Geoff Levand <geoffrey.levand at am.sony.com>
> ---
> 
> v2: o Add locking to lmb_find().

I'm not against this patch, but I'm pretty sure it's not
necessary.  Isn't memory hotplug already synchronized at
a higher level?

If not, it should be.