[Intel-gfx] [PATCH 04/13] drm/i915: Use vma->exec_entry as our double-entry placeholder

[Chris Wilson]

On Fri, Mar 31, 2017 at 12:29:23PM +0300, Joonas Lahtinen wrote:
> Did you intend to rename too, or where did the title come from?

It's accurate. We have vma->exec_list (later vma->exec_link) that is the
vma's location on the execbufer list, and we have vma->exec_entry which
is the vma's execobj. Currently we use list_empty(&vma->exec_list) to
determine if this vma is already in use in an execbuf ioctl (which is
two pointer loads, and two pointer sets to mark as unused) vs just
checking !vma->exec_entry which is simply. The caveat is to remember to
clear vma->exec_entry -- but that was already taken care of when I
rebased a later patch to fix softpinning.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre