watchdog/core: Further simplify sysctl handling

Use a single function to update sysctl changes. This is not a high
frequency user space interface and it's root only.

Preparatory patch to cleanup the sysctl variable handling.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194147.549114957@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 762d3ed82a087ac0e341e647c62d3e57ed695e55..ca8747221e870e7147e7df819048cac065d8eabc 100644 (file)
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -507,11 +507,8 @@ static void softlockup_park_all_threads(void)
        softlockup_update_smpboot_threads();
 }
 
-/*
- * Park threads which are not longer enabled and unpark threads which have
- * been newly enabled.
- */
-static void softlockup_update_threads(void)
+/* Unpark enabled threads */
+static void softlockup_unpark_threads(void)
 {
        cpumask_copy(&watchdog_allowed_mask, &watchdog_cpumask);
        softlockup_update_smpboot_threads();
@@ -522,7 +519,7 @@ static void softlockup_reconfigure_threads(bool enabled)
        softlockup_park_all_threads();
        set_sample_period();
        if (enabled)
-               softlockup_update_threads();
+               softlockup_unpark_threads();
 }
 
 /*
@@ -563,7 +560,6 @@ static inline void watchdog_unpark_threads(void) { }
 static inline int watchdog_enable_all_cpus(void) { return 0; }
 static inline void watchdog_disable_all_cpus(void) { }
 static inline void softlockup_init_threads(void) { }
-static inline void softlockup_update_threads(void) { }
 static inline void softlockup_reconfigure_threads(bool enabled) { }
 #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */
 
@@ -598,11 +594,11 @@ void lockup_detector_soft_poweroff(void)
 
 #ifdef CONFIG_SYSCTL
 
-/*
- * Update the run state of the lockup detectors.
- */
+/* Propagate any changes to the watchdog threads */
 static void proc_watchdog_update(void)
 {
+       /* Remove impossible cpus to keep sysctl output clean. */
+       cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
        softlockup_reconfigure_threads(watchdog_enabled && watchdog_thresh);
        watchdog_nmi_reconfigure();
 }
@@ -721,15 +717,6 @@ int proc_watchdog_thresh(struct ctl_table *table, int write,
        return err;
 }
 
-static void proc_watchdog_cpumask_update(void)
-{
-       /* Remove impossible cpus to keep sysctl output clean. */
-       cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
-
-       softlockup_update_threads();
-       watchdog_nmi_reconfigure();
-}
-
 /*
  * The cpumask is the mask of possible cpus that the watchdog can run
  * on, not the mask of cpus it is actually running on.  This allows the
@@ -746,7 +733,7 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
 
        err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
        if (!err && write)
-               proc_watchdog_cpumask_update();
+               proc_watchdog_update();
 
        mutex_unlock(&watchdog_mutex);
        cpu_hotplug_enable();