[PATCH] silence unused pgdat warning from alloc_bootmem_node and friends

[PATCH] silence unused pgdat warning from alloc_bootmem_node and friends

x86 NUMA systems only define bootmem for node 0.  alloc_bootmem_node() and
friends therefore ignore the passed pgdat and use NODE_DATA(0) in all
cases.  This leads to the following warnings as we are not using the passed
parameter:

  .../mm/page_alloc.c: In function 'zone_wait_table_init':
  .../mm/page_alloc.c:2259: warning: unused variable 'pgdat'

One option would be to define all variables used with these macros
__attribute__ ((unused)), but this would leave us exposed should these
become genuinely unused.

The key here is that we _are_ using the value, we ignore it but that is a
deliberate action.  This patch adds a nested local variable within the
alloc_bootmem_node helper to which the pgdat parameter is assigned making
it 'used'.  The nested local is marked __attribute__ ((unused)) to silence
this same warning for it.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>