On Mon 2015-09-28 22:44 +0200, Ulrich Obergfell wrote:
> update_watchdog_all_cpus() now passes errors from watchdog_park_threads()
> up to functions in the call chain. This allows watchdog_enable_all_cpus()
> and proc_watchdog_update() to handle such errors too.
>
> Signed-off-by: Ulrich Obergfell <uober...@redhat.com>
> ---
> kernel/watchdog.c | 30 +++++++++++++++++++++++-------
> 1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index eb9527c..457113c 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -731,10 +731,17 @@ void lockup_detector_resume(void)
> mutex_unlock(&watchdog_proc_mutex);
> }
>
> -static void update_watchdog_all_cpus(void)
> +static int update_watchdog_all_cpus(void)
> {
> - watchdog_park_threads();
> + int ret;
> +
> + ret = watchdog_park_threads();
> + if (ret)
> + return ret;
> +
> watchdog_unpark_threads();
> +
> + return 0;
> }
>
> static int watchdog_enable_all_cpus(void)
> @@ -753,9 +760,17 @@ static int watchdog_enable_all_cpus(void)
> * Enable/disable the lockup detectors or
> * change the sample period 'on the fly'.
> */
> - update_watchdog_all_cpus();
> + err = update_watchdog_all_cpus();
> +
> + if (err) {
> + watchdog_disable_all_cpus();
> + pr_err("Failed to update lockup detectors, disabled\n");
> + }
> }
>
> + if (err)
> + watchdog_enabled = 0;
> +
> return err;
> }
>
> @@ -851,12 +866,13 @@ static int proc_watchdog_common(int which, struct
> ctl_table *table, int write,
> } while (cmpxchg(&watchdog_enabled, old, new) != old);
>
> /*
> - * Update the run state of the lockup detectors.
> - * Restore 'watchdog_enabled' on failure.
> + * Update the run state of the lockup detectors. There is _no_
> + * need to check the value returned by proc_watchdog_update()
> + * and to restore the previous value of 'watchdog_enabled' as
> + * both lockup detectors are disabled if proc_watchdog_update()
> + * returns an error.
> */
> err = proc_watchdog_update();
> - if (err)
> - watchdog_enabled = old;
> }
> out:
> mutex_unlock(&watchdog_proc_mutex);Reviewed-by: Aaron Tomlin <atom...@redhat.com>
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