revert "cpumask: don't perform while loop in cpumask_next_and()"

Revert commit 534b483a ("cpumask: don't perform while loop in
cpumask_next_and()").

This was a minor optimization, but it puts a `struct cpumask' on the
stack, which consumes too much stack space.

Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Amir Vadai <amirv@mellanox.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lib/cpumask.c

@@ -16,11 +16,10 @@
 int cpumask_next_and(int n, const struct cpumask *src1p,
 		     const struct cpumask *src2p)
 {
-	struct cpumask tmp;
-
-	if (cpumask_and(&tmp, src1p, src2p))
-		return cpumask_next(n, &tmp);
-	return nr_cpu_ids;
+	while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
+		if (cpumask_test_cpu(n, src2p))
+			break;
+	return n;
 }
 EXPORT_SYMBOL(cpumask_next_and);