From 6b9dc4806b28214a4a260517e59439e0ac12a15e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 2 Oct 2017 12:34:50 +0200 Subject: [PATCH] watchdog/core, powerpc: Replace watchdog_nmi_reconfigure() The recent cleanup of the watchdog code split watchdog_nmi_reconfigure() into two stages. One to stop the NMI and one to restart it after reconfiguration. That was done by adding a boolean 'run' argument to the code, which is functionally correct but not necessarily a piece of art. Replace it by two explicit functions: watchdog_nmi_stop() and watchdog_nmi_start(). Fixes: 6592ad2fcc8f ("watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage") Requested-by: Linus 'Nursing his pet-peeve' Torvalds Signed-off-by: Thomas 'Mopping up garbage' Gleixner Acked-by: Michael Ellerman Cc: Peter Zijlstra Cc: Don Zickus Cc: Benjamin Herrenschmidt Cc: Nicholas Piggin Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710021957480.2114@nanos --- arch/powerpc/kernel/watchdog.c | 23 ++++++++++++++--------- include/linux/nmi.h | 3 ++- kernel/watchdog.c | 33 ++++++++++++++++++--------------- 3 files changed, 34 insertions(+), 25 deletions(-) diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index dfb067764480..2673ec8bec00 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -355,19 +355,24 @@ static void watchdog_calc_timeouts(void) wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5; } -void watchdog_nmi_reconfigure(bool run) +void watchdog_nmi_stop(void) { int cpu; cpus_read_lock(); - if (!run) { - for_each_cpu(cpu, &wd_cpus_enabled) - stop_wd_on_cpu(cpu); - } else { - watchdog_calc_timeouts(); - for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) - start_wd_on_cpu(cpu); - } + for_each_cpu(cpu, &wd_cpus_enabled) + stop_wd_on_cpu(cpu); + cpus_read_unlock(); +} + +void watchdog_nmi_start(void) +{ + int cpu; + + cpus_read_lock(); + watchdog_calc_timeouts(); + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) + start_wd_on_cpu(cpu); cpus_read_unlock(); } diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 89ba8b23c6fe..0c9ed49fb21a 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -109,7 +109,8 @@ static inline int hardlockup_detector_perf_init(void) { return 0; } # endif #endif -void watchdog_nmi_reconfigure(bool run); +void watchdog_nmi_stop(void); +void watchdog_nmi_start(void); /** * touch_nmi_watchdog - restart NMI watchdog timeout. diff --git a/kernel/watchdog.c b/kernel/watchdog.c index f6ef163b72cd..6ad6226535d0 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -123,24 +123,27 @@ int __weak __init watchdog_nmi_probe(void) } /** - * watchdog_nmi_reconfigure - Optional function to reconfigure NMI watchdogs - * @run: If false stop the watchdogs on all enabled CPUs - * If true start the watchdogs on all enabled CPUs + * watchdog_nmi_stop - Stop the watchdog for reconfiguration * - * The core call order is: - * watchdog_nmi_reconfigure(false); + * The reconfiguration steps are: + * watchdog_nmi_stop(); * update_variables(); - * watchdog_nmi_reconfigure(true); + * watchdog_nmi_start(); + */ +void __weak watchdog_nmi_stop(void) { } + +/** + * watchdog_nmi_start - Start the watchdog after reconfiguration * - * The second call which starts the watchdogs again guarantees that the - * following variables are stable across the call. + * Counterpart to watchdog_nmi_stop(). + * + * The following variables have been updated in update_variables() and + * contain the currently valid configuration: * - watchdog_enabled * - watchdog_thresh * - watchdog_cpumask - * - * After the call the variables can be changed again. */ -void __weak watchdog_nmi_reconfigure(bool run) { } +void __weak watchdog_nmi_start(void) { } /** * lockup_detector_update_enable - Update the sysctl enable bit @@ -551,13 +554,13 @@ static void softlockup_unpark_threads(void) static void softlockup_reconfigure_threads(void) { - watchdog_nmi_reconfigure(false); + watchdog_nmi_stop(); softlockup_park_all_threads(); set_sample_period(); lockup_detector_update_enable(); if (watchdog_enabled && watchdog_thresh) softlockup_unpark_threads(); - watchdog_nmi_reconfigure(true); + watchdog_nmi_start(); } /* @@ -602,9 +605,9 @@ static inline void watchdog_disable_all_cpus(void) { } static inline void softlockup_init_threads(void) { } static void softlockup_reconfigure_threads(void) { - watchdog_nmi_reconfigure(false); + watchdog_nmi_stop(); lockup_detector_update_enable(); - watchdog_nmi_reconfigure(true); + watchdog_nmi_start(); } #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */ -- 2.20.1