lib/test_vmalloc.c: do not create cpumask_t variable on stack

On my "Intel(R) Xeon(R) W-2135 CPU @ 3.70GHz" system(12 CPUs) i get the
warning from the compiler about frame size:

   warning: the frame size of 1096 bytes is larger than 1024 bytes [-Wframe-larger-than=]

the size of cpumask_t depends on number of CPUs, therefore just make use
of cpumask_of() in set_cpus_allowed_ptr() as a second argument.

Link: http://lkml.kernel.org/r/20190418193925.9361-1-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_vmalloc.c

@@ -383,14 +383,14 @@ static void shuffle_array(int *arr, int n)
 static int test_func(void *private)
 {
 	struct test_driver *t = private;
-	cpumask_t newmask = CPU_MASK_NONE;
 	int random_array[ARRAY_SIZE(test_case_array)];
 	int index, i, j, ret;
 	ktime_t kt;
 	u64 delta;
 
-	cpumask_set_cpu(t->cpu, &newmask);
-	set_cpus_allowed_ptr(current, &newmask);
+	ret = set_cpus_allowed_ptr(current, cpumask_of(t->cpu));
+	if (ret < 0)
+		pr_err("Failed to set affinity to %d CPU\n", t->cpu);
 
 	for (i = 0; i < ARRAY_SIZE(test_case_array); i++)
 		random_array[i] = i;