[Intel-gfx] [PATCH] drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference

[Chris Wilson]

We are only documenting that the read is outside of the lock, and do not
require strict ordering on the operation. In this case the more relaxed
lockless_dereference() will suffice.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Julia Lawall <julia.lawall at lip6.fr>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Emil Velikov <emil.l.velikov at gmail.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 0a06f9120b5a..ce54e985d91b 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -464,7 +464,7 @@ static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
 
 	/* Sometimes user space wants everything disabled, so don't steal the
 	 * display if there's a master. */
-	if (READ_ONCE(dev->master))
+	if (lockless_dereference(dev->master))
 		return false;
 
 	drm_for_each_crtc(crtc, dev) {
-- 
2.8.1