[tip:core/urgent] watchdog/core: Further simplify sysctl handling

tip-bot for Thomas Gleixner
2017-09-14T10:52:20Z

Commit-ID: e8b62b2dd14f8f2427856ba24cb7db922bda9bfd
Gitweb: http://git.kernel.org/tip/e8b62b2dd14f8f2427856ba24cb7db922bda9bfd
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 12 Sep 2017 21:37:12 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 14 Sep 2017 11:41:06 +0200

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>
---
kernel/watchdog.c | 27 +++++++--------------------
1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 762d3ed..ca87472 100644
--- 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();