tree 8b1c971efc4773effa1fe21ba31ac49dd9334ef9
parent 3b5724d702ef24ee41ca008a1fab1cf94f3d31b5
author Chris Wilson <chris@chris-wilson.co.uk> 1471537010 +0100
committer Chris Wilson <chris@chris-wilson.co.uk> 1471556205 +0100

drm/i915: Pin the pages first in shmem prepare read/write

There is an improbable, but not impossible, case that if we leave the
pages unpin as we operate on the object, then somebody via the shrinker
may steal the lock (which lock? right now, it is struct_mutex, THE lock)
and change the cache domains after we have already inspected them.

(Whilst here, avail ourselves of the opportunity to take a couple of
steps to make the two functions look more similar.)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-11-chris@chris-wilson.co.uk