[Intel-gfx] [PATCH] drm/i915: Use GEM_WARN_ON to catch invalid engine indices.

[Tvrtko Ursulin]

On 01/03/2017 20:27, Michal Wajdeczko wrote:
> Engine related definitions are located in different files
> and it is easy to break their cross dependency.
>
> v2: compare against array size
> v3: don't use BUILD_BUG (Tvrtko)
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_engine_cs.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index a238304..8675164 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -89,7 +89,11 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
>  	const struct engine_info *info = &intel_engines[id];

Just need to move this assignment after the assert.

>  	struct intel_engine_cs *engine;
>
> -	GEM_BUG_ON(dev_priv->engine[id]);
> +	if (GEM_WARN_ON((unsigned)id >= ARRAY_SIZE(intel_engines)))
> +		return -EINVAL;
> +	if (GEM_WARN_ON((unsigned)id >= ARRAY_SIZE(dev_priv->engine)))
> +		return -EINVAL;
> +
>  	engine = kzalloc(sizeof(*engine), GFP_KERNEL);
>  	if (!engine)
>  		return -ENOMEM;
> @@ -105,6 +109,7 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
>  	/* Nothing to do here, execute in order of dependencies */
>  	engine->schedule = NULL;
>
> +	GEM_BUG_ON(dev_priv->engine[id]);

It doesn't really matter but I think moving this one was not needed.

>  	dev_priv->engine[id] = engine;
>  	return 0;
>  }
>

Regards,

Tvrtko