[PATCH 06/10] watchdog/buddy: Cleanup how watchdog_buddy_check_hardlockup() is called

From: Douglas Anderson
Date: Fri May 26 2023 - 21:43:02 EST


In the patch ("watchdog/hardlockup: detect hard lockups using
secondary (buddy) CPUs"), we added a call from the common watchdog.c
file into the buddy. That call could be done more cleanly.
Specifically:
1. If we move the call into watchdog_hardlockup_kick() then it keeps
watchdog_timer_fn() simpler.
2. We don't need to pass an "unsigned long" to the buddy for the timer
count. In the patch ("watchdog/hardlockup: add a "cpu" param to
watchdog_hardlockup_check()") the count was changed to "atomic_t"
which is backed by an int, so we should match types.

Suggested-by: Petr Mladek <pmladek@xxxxxxxx>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---

include/linux/nmi.h | 4 ++--
kernel/watchdog.c | 15 +++++++--------
kernel/watchdog_buddy.c | 2 +-
3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 6c6a5ce77c66..43893e5f858a 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -114,9 +114,9 @@ void watchdog_hardlockup_disable(unsigned int cpu);
void lockup_detector_reconfigure(void);

#ifdef CONFIG_HARDLOCKUP_DETECTOR_BUDDY
-void watchdog_buddy_check_hardlockup(unsigned long hrtimer_interrupts);
+void watchdog_buddy_check_hardlockup(int hrtimer_interrupts);
#else
-static inline void watchdog_buddy_check_hardlockup(unsigned long hrtimer_interrupts) {}
+static inline void watchdog_buddy_check_hardlockup(int hrtimer_interrupts) {}
#endif

/**
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 85f4839b6faf..6cc46b8e3d07 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -131,9 +131,12 @@ static bool is_hardlockup(unsigned int cpu)
return false;
}

-static unsigned long watchdog_hardlockup_kick(void)
+static void watchdog_hardlockup_kick(void)
{
- return atomic_inc_return(this_cpu_ptr(&hrtimer_interrupts));
+ int new_interrupts;
+
+ new_interrupts = atomic_inc_return(this_cpu_ptr(&hrtimer_interrupts));
+ watchdog_buddy_check_hardlockup(new_interrupts);
}

void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
@@ -195,7 +198,7 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)

#else /* CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */

-static inline unsigned long watchdog_hardlockup_kick(void) { return 0; }
+static inline void watchdog_hardlockup_kick(void) { }

#endif /* !CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */

@@ -449,15 +452,11 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
struct pt_regs *regs = get_irq_regs();
int duration;
int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
- unsigned long hrtimer_interrupts;

if (!watchdog_enabled)
return HRTIMER_NORESTART;

- hrtimer_interrupts = watchdog_hardlockup_kick();
-
- /* test for hardlockups */
- watchdog_buddy_check_hardlockup(hrtimer_interrupts);
+ watchdog_hardlockup_kick();

/* kick the softlockup detector */
if (completion_done(this_cpu_ptr(&softlockup_completion))) {
diff --git a/kernel/watchdog_buddy.c b/kernel/watchdog_buddy.c
index fee45af2e5bd..3ffc5f2ede5a 100644
--- a/kernel/watchdog_buddy.c
+++ b/kernel/watchdog_buddy.c
@@ -72,7 +72,7 @@ void watchdog_hardlockup_disable(unsigned int cpu)
cpumask_clear_cpu(cpu, &watchdog_cpus);
}

-void watchdog_buddy_check_hardlockup(unsigned long hrtimer_interrupts)
+void watchdog_buddy_check_hardlockup(int hrtimer_interrupts)
{
unsigned int next_cpu;

--
2.41.0.rc0.172.g3f132b7071-goog