[Intel-gfx] [PATCH 0/1] drm/i915: intel_ring_initialized() must be simple and inline

[Dave Gordon]

Based on Chris Wilson's patch from 6 months ago, rebased and adapted.

The idea is to use ring->dev as an indicator showing which engines have
been initialised and are therefore to be included in iterations that use
for_each_ring(). This allows us to avoid multiple memory references and
a (non-inlined) function call on each iteration of each such loop.

This version differs from Chris' primarily in the error cleanup paths,
where initialisation has failed and we therefore want to mark an engine
as NOT initialised. I have made the ring_cleanup() functions callable from
the failure path of the ring_init() code, rather than duplicating all the
steps to tear down a partially-constructed state. This also increases
symmetry; ring->dev is set at the start of ring_init, and cleared at the
end of ring_cleanup, in both the normal and error cases.