Re: [PATCH]: mutex: Fix !CONFIG_MUTEX_SPIN_ON_OWNER compile warning

[Frederic Weisbecker <fweisbec@gmail.com>]

On Thu, May 27, 2010 at 03:07:40PM -0400, Prarit Bhargava wrote:
> Fixes linux-next !CONFIG_MUTEX_SPIN_ON_OWNER compile warning:
> 
> kernel/mutex.c: In function ‘__mutex_lock_common’:
> kernel/mutex.c:148: error: unused variable ‘timeout’
> 
> timeout is only used if CONFIG_MUTEX_SPIN_ON_OWNER is on.
> 
> Signed-off-by: Prarit Bhargava <prarit@redhat.com>
> 
> diff --git a/kernel/mutex.c b/kernel/mutex.c
> index 7d4626b..c262942 100644
> --- a/kernel/mutex.c
> +++ b/kernel/mutex.c
> @@ -145,7 +145,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
>  	struct task_struct *task = current;
>  	struct mutex_waiter waiter;
>  	unsigned long flags;
> +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
>  	unsigned long timeout;
> +#endif



Andrew had a patch that fixed it with a "__used" tag.
Either way that doesn't look much proper.

It would be much nicer to put the mutex spinning in a separate
function, that would be a stub with !CONFIG_MUTEX_SPIN_ON_OWNER.