[Intel-gfx] [PATCH] drm/i915: Check for an invalid seqno before __i915_gem_request_started

[Tvrtko Ursulin]

On 08/03/2017 14:50, Chris Wilson wrote:
> On Wed, Mar 08, 2017 at 02:45:16PM +0000, Tvrtko Ursulin wrote:
>>
>> On 08/03/2017 14:22, Chris Wilson wrote:
>>> __i915_gem_request_started() asserts that the seqno is valid, but
>>> i915_spin_request() was not checking before querying whether the request
>>> had started.
>>>
>>> Reported-by: Michał Winiarski <michal.winiarski at intel.com>
>>> Fixes: 754c9fd57649 ("drm/i915: Protect the request->global_seqno with the engine->timeline lock")
>>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>> Cc: Michał Winiarski <michal.winiarski at intel.com>
>>> ---
>>> drivers/gpu/drm/i915/i915_gem_request.h | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
>>> index 6fdfb801bcee..cb4e7f3e279e 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem_request.h
>>> +++ b/drivers/gpu/drm/i915/i915_gem_request.h
>>> @@ -348,6 +348,9 @@ static inline bool i915_spin_request(const struct drm_i915_gem_request *request,
>>> 	u32 seqno;
>>>
>>> 	seqno = i915_gem_request_global_seqno(request);
>>> +	if (!seqno)
>>> +		return 0;
>>> +
>>> 	return (__i915_gem_request_started(request, seqno) &&
>>> 		__i915_spin_request(request, seqno, state, timeout_us));
>>> }
>>>
>>
>> Looks equivalent to just calling i915_gem_request_started instead of
>> __i915_gem_request_started.
>
> We want to pass the same seqno onto __i915_spin_request, but yeah, very
> similar.

Ah yes, my bad.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko