Hi Guenter,

Great thanks for your suggestion,

I have put this kind of validation into watchdog_pretimeout_invalid
and watchdog_timeout_invalid.

So :

(1)
 set_timeout(10);   ------> if this setting is successful
 set_pretimeout(20); ----->  return fail (-EINVAL)


(2)
set_timeout(10);  ------> if this setting is successful
set_pretimeout(10); ----->  return fail (-EINVAL)

this kind of situation will not result in an invalid / unexpected timeout value.

you will see this change in my next patchset

On 21 May 2015 at 23:32, Guenter Roeck [off-list ref] wrote:

On Thu, May 21, 2015 at 04:32:34PM +0800, fu.wei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org wrote:

quoted

From: Fu Wei <redacted>

Also update Documentation/watchdog/watchdog-kernel-api.txt to
introduce:
(1)the new elements in the watchdog_device and watchdog_ops struct;
(2)the new API "watchdog_init_timeouts".

Reasons:
(1)kernel already has two watchdog drivers are using "pretimeout":
      drivers/char/ipmi/ipmi_watchdog.c
      drivers/watchdog/kempld_wdt.c(but the definition is different)
(2)some other dirvers are going to use this: ARM SBSA Generic Watchdog

Signed-off-by: Fu Wei <redacted>
---

[ ... ]

quoted

+/* Use the following function to check if a pretimeout value is invalid */
+static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
+                                            unsigned int t)
+{
+     return ((wdd->max_pretimeout != 0) &&
+             (t < wdd->min_pretimeout || t > wdd->max_pretimeout));
+}

Should this function also enforce "t < wdd->timeout", and
should watchdog_timeout_invalid() enforce "t > wdd->pretimeout" ?

Thanks,
Guenter

-- 
Best regards,

Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
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