linux-kernel - [PATCH 4/4] watchdog: provide watchdog

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Message-Id: <20170525082856.21685-5-npiggin@gmail.com>
Date:   Thu, 25 May 2017 18:28:56 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     Don Zickus <dzickus@...hat.com>
Cc:     Nicholas Piggin <npiggin@...il.com>, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org
Subject: [PATCH 4/4] watchdog: provide watchdog_reconfigure() for arch watchdogs

After reconfiguring watchdog sysctls etc., architecture specific
watchdogs may not get all their parameters updated.

watchdog_reconfigure() can be implemented to pull the new values
in and set the arch NMI watchdog.

Signed-off-by: Nicholas Piggin <npiggin@...il.com>
---
 kernel/watchdog.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index deb010505646..d2996f5bf551 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -120,6 +120,11 @@ void __weak watchdog_nmi_disable(unsigned int cpu)
 {
 }
 
+void __weak watchdog_nmi_reconfigure(void)
+{
+}
+
+
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
 
 /* Helper for online, unparked cpus. */
@@ -597,6 +602,12 @@ static void watchdog_disable_all_cpus(void)
 	}
 }
 
+static int watchdog_update_cpus(void)
+{
+	return smpboot_update_cpumask_percpu_thread(
+		    &watchdog_threads, &watchdog_cpumask);
+}
+
 #else /* SOFTLOCKUP */
 static int watchdog_park_threads(void)
 {
@@ -616,6 +627,10 @@ static void watchdog_disable_all_cpus(void)
 {
 }
 
+static int watchdog_update_cpus(void)
+{
+}
+
 static void set_sample_period(void)
 {
 }
@@ -648,6 +663,8 @@ int lockup_detector_suspend(void)
 		watchdog_enabled = 0;
 	}
 
+	watchdog_nmi_reconfigure();
+
 	mutex_unlock(&watchdog_proc_mutex);
 
 	return ret;
@@ -668,6 +685,8 @@ void lockup_detector_resume(void)
 	if (watchdog_running && !watchdog_suspended)
 		watchdog_unpark_threads();
 
+	watchdog_nmi_reconfigure();
+
 	mutex_unlock(&watchdog_proc_mutex);
 	put_online_cpus();
 }
@@ -693,6 +712,8 @@ static int proc_watchdog_update(void)
 	else
 		watchdog_disable_all_cpus();
 
+	watchdog_nmi_reconfigure();
+
 	return err;
 
 }
@@ -878,12 +899,11 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
 			 * a temporary cpumask, so we are likely not in a
 			 * position to do much else to make things better.
 			 */
-#ifdef CONFIG_SOFTLOCKUP_DETECTOR
-			if (smpboot_update_cpumask_percpu_thread(
-				    &watchdog_threads, &watchdog_cpumask) != 0)
+			if (watchdog_update_cpus() != 0)
 				pr_err("cpumask update failed\n");
-#endif
 		}
+
+		watchdog_nmi_reconfigure();
 	}
 out:
 	mutex_unlock(&watchdog_proc_mutex);
-- 
2.11.0