watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()

There's no reason to make a copy of the "watchdog_cpus" locally in
watchdog_next_cpu().  Making a copy wouldn't make things any more race
free and we're just reading the value so there's no need for a copy.

Link: https://lkml.kernel.org/r/20230526184139.7.If466f9a2b50884cbf6a1d8ad05525a2c17069407@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: dianders

kernel/watchdog_buddy.c

@@ -10,12 +10,11 @@ static cpumask_t __read_mostly watchdog_cpus;
 
 static unsigned int watchdog_next_cpu(unsigned int cpu)
 {
-	cpumask_t cpus = watchdog_cpus;
 	unsigned int next_cpu;
 
-	next_cpu = cpumask_next(cpu, &cpus);
+	next_cpu = cpumask_next(cpu, &watchdog_cpus);
 	if (next_cpu >= nr_cpu_ids)
-		next_cpu = cpumask_first(&cpus);
+		next_cpu = cpumask_first(&watchdog_cpus);
 
 	if (next_cpu == cpu)
 		return nr_cpu_ids;