Re: [PATCH 7/10 v2] Generic Watchdog Timer Driver

[Alejandro Cabrera <acabrera@udio.cujae.edu.cu>]

Hi
> --- linux-2.6.38-generic-part6/drivers/watchdog/core/watchdog_dev.c	2011-06-16 22:52:56.763937624 +0200
> +++ linux-2.6.38-generic-part7/drivers/watchdog/core/watchdog_dev.c	2011-06-17 09:52:32.870632731 +0200
> @@ -126,11 +126,15 @@
>    *	Stop the watchdog if it is still active and unmark it active.
>    *	This function returns zero on success or a negative errno code for
>    *	failure.
> + *	If the 'nowayout' feature was set, the watchdog cannot be stopped.
>    */
>
>   static int watchdog_stop(struct watchdog_device *wddev)
>   {
> -	int err;
> +	int err = -1;
> +
> +	if (test_bit(WDOG_NO_WAY_OUT,&wdd->status))
> +		return err;
>

If you return err at this point you never clean the bit WDOG_ACTIVE then 
the timer will keep resetting the wdt because the bit is still active.

>   	if (test_bit(WDOG_ACTIVE,&wdd->status)) {
>   		err = wddev->ops->stop(wddev);
> @@ -151,7 +155,7 @@
>    *
>    *	A write to a watchdog device is defined as a keepalive ping.
>    *	Writing the magic 'V' sequence allows the next close to turn
> - *	off the watchdog.
> + *	off the watchdog (if 'nowayout' is not set).
>    */
>
>   static ssize_t watchdog_write(struct file *file, const char __user *data,
> diff -urN linux-2.6.38-generic-part6/include/linux/watchdog.h linux-2.6.38-generic-part7/include/linux/watchdog.h
> --- linux-2.6.38-generic-part6/include/linux/watchdog.h	2011-06-17 12:17:15.285063678 +0200
> +++ linux-2.6.38-generic-part7/include/linux/watchdog.h	2011-06-17 12:17:39.205063756 +0200
> @@ -86,6 +86,7 @@
>   #define WDOG_DEV_OPEN		1	/* is the watchdog opened via
>   					 * /dev/watchdog */
>   #define WDOG_EXPECT_RELEASE	2	/* did we receive the magic char ? */
> +#define WDOG_NO_WAY_OUT		3	/* is 'nowayout' feature set ? */
>   };
>
>   /* drivers/watchdog/core/watchdog_core.c */
> --
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