[PATCH V2] watchdog: ignore nohz_full cores in new cpumask

[Zqiang]

If the nohz_full is enabled, when update watchdog_mask, the
nohz_full cores should be ignored.

Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx>
---
 v1->v2:
 if watchdog_cpumask became empty, set housekeeping_cpumask.

 kernel/watchdog.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index ad912511a0c0..6f0c5528b399 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -628,7 +628,9 @@ void lockup_detector_soft_poweroff(void)
 static void proc_watchdog_update(void)
 {
 	/* Remove impossible cpus to keep sysctl output clean. */
-	cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
+	cpumask_and(&watchdog_cpumask, &watchdog_cpumask, housekeeping_cpumask(HK_FLAG_TIMER));
+	if (cpumask_empty(&watchdog_cpumask))
+		cpumask_copy(&watchdog_cpumask, housekeeping_cpumask(HK_FLAG_TIMER));
 	lockup_detector_reconfigure();
 }
 
-- 
2.17.1