[PATCH 1/5] watchdog: starfive-wdt: Drop runtime PM reference if starting watchdog fails

[Guenter Roeck <linux@roeck-us.net>]

Commit 8f0ca55016a7 ("watchdog: starfive-wdt: Fix runtime PM leak in
starfive_wdt_pm_start()") switched starfive_wdt_pm_start() to
pm_runtime_resume_and_get() so the runtime PM usage counter is not
leaked when resuming the device fails. However, if starfive_wdt_start()
subsequently fails (for example, on a timeout in starfive_wdt_int_clr()),
starfive_wdt_pm_start() returns the error without releasing the runtime
PM reference acquired by pm_runtime_resume_and_get(). Because the
watchdog core does not invoke the stop callback when start fails, the
usage counter remains permanently elevated.

Drop the runtime PM reference with pm_runtime_put_sync() if
starfive_wdt_start() fails.

Fixes: db728ea9c7be ("drivers: watchdog: Add StarFive Watchdog driver")
Cc: Xingyu Wu <xingyu.wu@starfivetech.com>
Cc: Ziv Xu <ziv.xu@starfivetech.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/watchdog/starfive-wdt.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/starfive-wdt.c b/drivers/watchdog/starfive-wdt.c
index 044b4fdb7350..ab6920b8d7d8 100644
--- a/drivers/watchdog/starfive-wdt.c
+++ b/drivers/watchdog/starfive-wdt.c
@@ -372,12 +372,17 @@ static void starfive_wdt_stop(struct starfive_wdt *wdt)
 static int starfive_wdt_pm_start(struct watchdog_device *wdd)
 {
 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
-	int ret = pm_runtime_resume_and_get(wdd->parent);
+	int ret;
 
+	ret = pm_runtime_resume_and_get(wdd->parent);
 	if (ret < 0)
 		return ret;
 
-	return starfive_wdt_start(wdt);
+	ret = starfive_wdt_start(wdt);
+	if (ret)
+		pm_runtime_put_sync(wdd->parent);
+
+	return ret;
 }
 
 static int starfive_wdt_pm_stop(struct watchdog_device *wdd)
-- 
2.45.2