Re: [PATCH] watchdog: only run driver set_pretimeout op if device supports it

From: Guenter Roeck
Date: Sun Jun 27 2021 - 11:01:13 EST


On 6/26/21 4:47 PM, Curtis Klein wrote:
Some watchdog devices might conditionally support pretimeouts (e.g. if
an interrupt is exposed for the device) but some watchdog drivers might
still define the set_pretimeout operation (e.g. the mtk_wdt driver) and
indicate support at runtime through the WDIOF_PRETIMEOUT flag. If the
kernel is compiled with CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT enabled,
watchdog_set_pretimeout would run the driver specific set_pretimeout
even if WDIOF_PRETIMEOUT is not set which might have unintended
consequences.

So this change checks that the device flags and only runs the driver
operation if pretimeouts are supported.

Signed-off-by: Curtis Klein <curtis.klein@xxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

---
drivers/watchdog/watchdog_dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 3bab324..5bf795c 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -401,7 +401,7 @@ static int watchdog_set_pretimeout(struct watchdog_device *wdd,
if (watchdog_pretimeout_invalid(wdd, timeout))
return -EINVAL;
- if (wdd->ops->set_pretimeout)
+ if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT))
err = wdd->ops->set_pretimeout(wdd, timeout);
else
wdd->pretimeout = timeout;