drm/i915: Compact memcmp in i915_vma_compare()

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In preparation for the next patch to convert to using an anonymous union
and leaving the excess bytes in the union uninitialised, we first need
to make sure we do not compare using those uninitialised bytes. We also
want to preserve the compactness of the code, avoiding a second call to
memcmp or introducing a switch, so we take advantage of using the type
as an encoded size (as well as a unique identifier for each type of view).

v2: Add the rationale for why we encode size into ggtt_view.type as a
comment before the memcmp()
v3: Use a switch to also assert that no two i915_ggtt_view_type have the same
value.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170114002827.31315-3-chris@chris-wilson.co.uk

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This commit is contained in:

Chris Wilson 2017-01-14 00:28:23 +00:00

parent 8d9046ad5d

commit 992e418dd9

2 changed files with 35 additions and 13 deletions

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28

drivers/gpu/drm/i915/i915_gem_gtt.h

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20

drivers/gpu/drm/i915/i915_vma.h

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