Re: [PATCH v3] drm/i915: Small compaction of the engine init code

Chris Wilson
2016-06-23T11:25:20Z

On Thu, Jun 23, 2016 at 12:12:29PM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Effectively removes one layer of indirection between the mask of
> possible engines and the engine constructors. Instead of spelling
> out in code the mapping of HAS_<engine> to constructors, makes
> more use of the recently added data driven approach by putting
> engine constructor vfuncs into the table as well.
>
> Effect is fewer lines of source and smaller binary.
>
> At the same time simplify the error handling since engine
> destructors can run on unitialized engines anyway.
>
> Similar approach could be done for legacy submission is wanted.
>
> v2: Removed ugly BUILD_BUG_ONs in favour of newly introduced
> ENGINE_MASK and HAS_ENGINE macros.
> Also removed the forward declarations by shuffling functions
> around.
>
> v3: Warn when logical_rings table does not contain enough data
> and disable the engines which could not be initialized.
> (Chris Wilson)

I was happy with the BUILD_BUG suggestion :)

> + for (i = 0;
> + i < I915_NUM_ENGINES && i < ARRAY_SIZE(logical_rings); i++) {

HAS_ENGINE() == false if i >= I915_NUM_ENGINES
-Chris

--
Chris Wilson, Intel Open Source Technology Centre