Messages in this thread | | | Date | Mon, 11 Aug 2014 20:55:07 +0200 | From | Hans de Goede <> | Subject | Re: [PATCH] uas: replace WARN_ON_ONCE() with assert_spin_locked(). |
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Hi,
On 08/11/2014 08:19 PM, Guenter Roeck wrote: > 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.
I can see your point, but so far these paranoia checks have never triggered, and having them trigger _always_ one some uni-processor (which is the reason for this patch) to me seems the worse problem of the 2.
Ideally we would have a warn_spin_not_locked or such ...
Regards,
Hans
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