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

[Tvrtko Ursulin]

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.

Regards,

Tvrtko