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

[Jean Delvare]

On Wed, 17 Jun 2015 18:00:58 +0200, Lennart Poettering wrote:
> 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.

I feel even more sorry, I should have seen that :-( Patch v4 coming...

-- 
Jean Delvare
SUSE L3 Support