Re: [PATCH] uas: replace WARN_ON_ONCE() with assert_spin_locked().

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Aug 11, 2014 at 01:29:26PM +0530, Sanjeev Sharma wrote:
> spin_is_locked() always return false in uniprocessor configuration and therefore it
> would be advise to repalce with assert_spin_locked().
> 
> Signed-off-by: Sanjeev Sharma <Sanjeev_Sharma@mentor.com>
> ---
>  drivers/usb/storage/uas.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
> index 3f42785..8e5877d 100644
> --- a/drivers/usb/storage/uas.c
> +++ b/drivers/usb/storage/uas.c
> @@ -154,7 +154,7 @@ static void uas_mark_cmd_dead(struct uas_dev_info *devinfo,
>  	struct scsi_cmnd *cmnd = container_of(scp, struct scsi_cmnd, SCp);
>  
>  	uas_log_cmd_state(cmnd, caller);
> -	WARN_ON_ONCE(!spin_is_locked(&devinfo->lock));
> +	assert_spin_locked(&devinfo->lock);

Seems to me that replacing WARN_ON_ONCE (which may be annoying but only
creates a traceback, and only once) with assert_spin_locked (which
crashes the kernel) is a bit drastic.

Guenter