Commit 6b9dc480 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: 6592ad2f ("watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage")
Requested-by: default avatarLinus 'Nursing his pet-peeve' Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: default avatarThomas 'Mopping up garbage' Gleixner <tglx@linutronix.de>
Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710021957480.2114@nanos
parent 77c01d11

arch/powerpc/kernel/watchdog.c

+14 −9
Original line number Diff line number Diff line
@@ -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 {

	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();

}

include/linux/nmi.h

+2 −1
Original line number Diff line number Diff line
@@ -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.

kernel/watchdog.c

+18 −15
Original line number Diff line number Diff line
@@ -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 */

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