[PATCH v5 09/18] watchdog/hardlockup: Style changes to watchdog_hardlockup_check() / is_hardlockup()

Douglas Anderson
2023-05-19T17:40:42Z

These are tiny style changes:
- Add a blank line before a "return".
- Renames two globals to use the "watchdog_hardlockup" prefix.
- Store processor id in "unsigned int" rather than "int".
- Minor comment rewording.
- Use "else" rather than extra returns since it seemed more symmetric.

Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v5:
- watchdog_hardlockup_dumped_stacks => watchdog_hardlockup_all_cpu_dumped
- watchdog_hardlockup_processed => watchdog_hardlockup_warned

Changes in v4:
- ("Style changes to watchdog_hardlockup_check ...") new for v4.

kernel/watchdog.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 12ce37d76e7d..169e5dffbc00 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -89,8 +89,8 @@ __setup("nmi_watchdog=", hardlockup_panic_setup);

static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
-static DEFINE_PER_CPU(bool, hard_watchdog_warn);
-static unsigned long hardlockup_allcpu_dumped;
+static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned);
+static unsigned long watchdog_hardlockup_all_cpu_dumped;

static bool is_hardlockup(void)
{
@@ -100,6 +100,7 @@ static bool is_hardlockup(void)
return true;

__this_cpu_write(hrtimer_interrupts_saved, hrint);
+
return false;
}

@@ -110,21 +111,20 @@ static void watchdog_hardlockup_kick(void)

void watchdog_hardlockup_check(struct pt_regs *regs)
{
- /* check for a hardlockup
- * This is done by making sure our timer interrupt
- * is incrementing. The timer interrupt should have
- * fired multiple times before we overflow'd. If it hasn't
+ /*
+ * Check for a hardlockup by making sure the CPU's timer
+ * interrupt is incrementing. The timer interrupt should have
+ * fired multiple times before we overflow'd. If it hasn't
* then this is a good indication the cpu is stuck
*/
if (is_hardlockup()) {
- int this_cpu = smp_processor_id();
+ unsigned int this_cpu = smp_processor_id();

- /* only print hardlockups once */
- if (__this_cpu_read(hard_watchdog_warn) == true)
+ /* Only print hardlockups once. */
+ if (__this_cpu_read(watchdog_hardlockup_warned))
return;

- pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n",
- this_cpu);
+ pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", this_cpu);
print_modules();
print_irqtrace_events(current);
if (regs)
@@ -137,18 +137,16 @@ void watchdog_hardlockup_check(struct pt_regs *regs)
* generating interleaving traces
*/
if (sysctl_hardlockup_all_cpu_backtrace &&
- !test_and_set_bit(0, &hardlockup_allcpu_dumped))
+ !test_and_set_bit(0, &watchdog_hardlockup_all_cpu_dumped))
trigger_allbutself_cpu_backtrace();

if (hardlockup_panic)
nmi_panic(regs, "Hard LOCKUP");

- __this_cpu_write(hard_watchdog_warn, true);
- return;
+ __this_cpu_write(watchdog_hardlockup_warned, true);
+ } else {
+ __this_cpu_write(watchdog_hardlockup_warned, false);
}
-
- __this_cpu_write(hard_watchdog_warn, false);
- return;
}

#else /* CONFIG_HARDLOCKUP_DETECTOR_PERF */