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

From: Guenter Roeck
Date: Mon Aug 11 2014 - 14:19:14 EST


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@xxxxxxxxxx>
> ---
> 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
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