Re: [PATCH 7/7] powerpc numa: Consolidate assignment of cpus to nodes

[Dave Hansen <haveblue@us.ibm.com>]

On Mon, 2006-03-20 at 18:37 -0600, Nathan Lynch wrote:
> +       cpu_numa_callback(&ppc64_numa_nb, CPU_UP_PREPARE,
> +                         (void *)(unsigned long)boot_cpuid); 

That double-cast really caught my eye.  cpu_numa_callback() looks a
little bit confused about what type cpuids should be.

Its lcpu is an "unsigned long", but it has integers passed into it
(boot_cpuid), and calls map_cpu_to_node(lcpu, 0), where the first
argument is an integer, but an "unsigned long" is passed in.  This may
be harmless, but I still have to think about it, which is bad.

Seems like just making cpu_numa_callback()'s lcpu an int would get rid
of at least one net cast.  Why not just pass &boot_cpuid in there, and
do this:

	int lcpu = *(int *)hcpu;

That makes it _really_ obvious what is going on.  While it isn't
horribly uncommon to pass integers around inside of void*s, it can be a
bit confusing.  You also get readability issues with long<->int
conversions as you saw.

By the way, what do the "l" and "h" in front of "cpu" mean anyway?

-- Dave