lockdep: annotate reclaim context (__GFP_NOFS), fix

Impact: fix build warning

Fix:

  mm/vmscan.c: In function ‘kswapd’:
  mm/vmscan.c:1969: warning: ISO C90 forbids mixed declarations and code

node_to_cpumask_ptr(cpumask, pgdat->node_id), has a side-effect: it
defines the 'cpumask' local variable as well, so it has to go into
the variable definition section.

Sidenote: it might make sense to make this purpose of these macros
more apparent, by naming them the standard way, such as:

  DEFINE_node_to_cpumask_ptr(cpumask, pgdat->node_id);

(But that is outside the scope of this patch.)

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mike Travis <travis@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

mm/vmscan.c

@@ -1963,11 +1963,10 @@ static int kswapd(void *p)
 	struct reclaim_state reclaim_state = {
 		.reclaimed_slab = 0,
 	};
+	node_to_cpumask_ptr(cpumask, pgdat->node_id);
 
 	lockdep_set_current_reclaim_state(GFP_KERNEL);
 
-	node_to_cpumask_ptr(cpumask, pgdat->node_id);
-
 	if (!cpumask_empty(cpumask))
 		set_cpus_allowed_ptr(tsk, cpumask);
 	current->reclaim_state = &reclaim_state;