On 9/13/21 4:41 AM, Jan Kiszka wrote:
From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Prominent userspace - systemd - cannot handle watchdogs without
WDIOF_SETTIMEOUT, even if it was configured to the same time as the
driver selected or was used by firmware to start the watchdog. To avoid
failing in this case, implement a handler that only fails if a deviating
set_timeout is requested.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
NACK. This is a userspace problem. The ABI clearly states that
WDIOF_SETTIMEOUT is optional, and userspace must not depend on it.
We can not start making kernel changes just to make broken userspace
code happy. systemd should be fixed instead.
Guenter
---
See also https://github.com/systemd/systemd/issues/20683
drivers/watchdog/rti_wdt.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
index 359302f71f7e..365255b15a0d 100644
--- a/drivers/watchdog/rti_wdt.c
+++ b/drivers/watchdog/rti_wdt.c
@@ -173,13 +173,27 @@ static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd)
return timer_counter;
}
+static int rti_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ /*
+ * Updating the timeout after start is actually not supported, but
+ * let's ignore requests for the already configured value. Helps
+ * existing userspace such as systemd.
+ */
+ if (timeout != heartbeat)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
{
return rti_wdt_get_timeleft_ms(wdd) / 1000;
}
static const struct watchdog_info rti_wdt_info = {
- .options = WDIOF_KEEPALIVEPING,
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
.identity = "K3 RTI Watchdog",
};
@@ -187,6 +201,7 @@ static const struct watchdog_ops rti_wdt_ops = {
.owner = THIS_MODULE,
.start = rti_wdt_start,
.ping = rti_wdt_ping,
+ .set_timeout = rti_wdt_set_timeout,
.get_timeleft = rti_wdt_get_timeleft,
};
