watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called

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.

Link: https://lkml.kernel.org/r/20230526184139.6.I006c7d958a1ea5c4e1e4dc44a25596d9bb5fd3ba@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: dianders

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
 
 /**

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))) {

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;