kernel/smp.c:on_each_cpu_cond(): fix warning in fallback path

The rarely-executed memry-allocation-failed callback path generates a
WARN_ON_ONCE() when smp_call_function_single() succeeds.  Presumably
it's supposed to warn on failures.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/smp.c

@@ -670,7 +670,7 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
 			if (cond_func(cpu, info)) {
 				ret = smp_call_function_single(cpu, func,
 								info, wait);
-				WARN_ON_ONCE(!ret);
+				WARN_ON_ONCE(ret);
 			}
 		preempt_enable();
 	}