[systemd-devel] [PATCH v3] watchdog: Don't require WDIOC_SETOPTIONS/WDIOS_ENABLECARD

[Lennart Poettering]

On Wed, 17.06.15 17:49, Jean Delvare (jdelvare at suse.de) wrote:

> Not all watchdog drivers implement WDIOC_SETOPTIONS. Drivers which do
> not implement it have their device always enabled. So it's fine to
> report an error if WDIOS_DISABLECARD is passed and the ioctl is not
> implemented, however failing when WDIOS_ENABLECARD is passed and the
> ioctl is not implemented is not good: if the device was already
> enabled then WDIOS_ENABLECARD was a no-op and wasn't needed in the
> first place. So we can just ignore the error and continue.
> ---
> Changes since v2:
>  * Fix indentation (spaces not tabs.)
> 
> Changes since v1:
>  * Log WDIOC_SETOPTIONS/WDIOS_ENABLECARD failure at debug level if
>    ENOTTY is returned. Suggested by Lennart Poettering.
> 
>  src/shared/watchdog.c |    9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> --- systemd.orig/src/shared/watchdog.c	2015-06-17 13:09:40.808480605 +0200
> +++ systemd/src/shared/watchdog.c	2015-06-17 13:09:50.633687681 +0200
> @@ -60,8 +60,13 @@ static int update_timeout(void) {
>  
>                  flags = WDIOS_ENABLECARD;
>                  r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
> -                if (r < 0)
> -                        return log_warning_errno(errno, "Failed to enable hardware watchdog: %m");
> +                if (r < 0) {
> +                        /* ENOTTY means the watchdog is always enabled so we're fine */
> +                        log_full(errno == ENOTTY ? LOG_DEBUG : LOG_WARNING,
> +                                 "Failed to enable hardware watchdog: %m");
> +                        if (errno != ENOTTY)
> +                                return errno;
> +                }

Sorry, not sure how I missed that, but we return error as negative
integers. Must be "return -errno" instead of "return errno" hence. See
CODING_STYLE on this.

Lennart

-- 
Lennart Poettering, Red Hat