cpumask: introduce zalloc_cpumask_var

So can get cpumask_var with cpumask_clear

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 1f71b97..eb23aaa 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -119,6 +119,12 @@
 }
 EXPORT_SYMBOL(alloc_cpumask_var_node);
 
+bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
+{
+	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
+}
+EXPORT_SYMBOL(zalloc_cpumask_var_node);
+
 /**
  * alloc_cpumask_var - allocate a struct cpumask
  * @mask: pointer to cpumask_var_t where the cpumask is returned
@@ -135,6 +141,12 @@
 }
 EXPORT_SYMBOL(alloc_cpumask_var);
 
+bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
+{
+	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
+}
+EXPORT_SYMBOL(zalloc_cpumask_var);
+
 /**
  * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
  * @mask: pointer to cpumask_var_t where the cpumask is returned