Re: [PATCH] drm: Assert correct locking for drm_send_vblank_event

[Peter Hurley <peter@hurleysoftware.com>]

On 09/12/2014 12:04 PM, Chris Wilson wrote:
> On Fri, Sep 12, 2014 at 05:34:56PM +0200, Daniel Vetter wrote:
>> On Fri, Sep 12, 2014 at 04:23:29PM +0100, Chris Wilson wrote:
>>> On Fri, Sep 12, 2014 at 03:40:56PM +0200, Daniel Vetter wrote:
>>>> The comment says that the caller must hold the dev->event_lock
>>>> spinlock, so let's enforce this.
>>>>
>>>> A quick audit over all driver shows that except for the one place in
>>>> i915 which motivated this all callers fullfill this requirement
>>>> already.
>>>
>>> Replace the rogue WARN_ON_SMP(!spin_is_locked(&dev->event_lock)) in
>>> send_vblank_event() as well then.
>>
>> Meh, I've missed that one, that's actually better I think. I'll drop my
>> patch here.
> 
> I thought assert_spin_lock was the preferred form?

Actually, lockdep_assert_held() is the preferred form.

See https://lkml.org/lkml/2014/9/3/171

Regards,
Peter Hurley