[PATCH] for_each_possible_cpu: defines for_each_possible_cpu

for_each_cpu() is a for-loop over cpu_possible_map.  for_each_online_cpu is
for-loop cpu over cpu_online_map.  .....for_each_cpu() is not sufficiently
explicit and can lead to mistakes.

This patch adds for_each_possible_cpu() in preparation for the removal of
for_each_cpu().
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/linux/cpumask.h

@@ -67,7 +67,7 @@
  *
  * int any_online_cpu(mask)		First online cpu in mask
  *
- * for_each_cpu(cpu)			for-loop cpu over cpu_possible_map
+ * for_each_possible_cpu(cpu)		for-loop cpu over cpu_possible_map
  * for_each_online_cpu(cpu)		for-loop cpu over cpu_online_map
  * for_each_present_cpu(cpu)		for-loop cpu over cpu_present_map
  *
@@ -406,6 +406,7 @@ int __any_online_cpu(const cpumask_t *mask);
 #endif
 
 #define for_each_cpu(cpu)  for_each_cpu_mask((cpu), cpu_possible_map)
+#define for_each_possible_cpu(cpu)  for_each_cpu_mask((cpu), cpu_possible_map)
 #define for_each_online_cpu(cpu)  for_each_cpu_mask((cpu), cpu_online_map)
 #define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)