drm/i915: Implement pread without struct-mutex
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 28 Oct 2016 12:58:39 +0000 (13:58 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 28 Oct 2016 19:53:48 +0000 (20:53 +0100)
commitbb6dc8d96b683a6052162c36062cd8e9329e4f21
tree413228a81f960fae1ad9ac2bca62d6d97f573741
parent7dd737f377ffb59010b6811f934998d42f24a8bd
drm/i915: Implement pread without struct-mutex

We only need struct_mutex within pread for a brief window where we need
to serialise with rendering and control our cache domains. Elsewhere we
can rely on the backing storage being pinned, and forgive userspace any
races against us.

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/20161028125858.23563-16-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem.c