drm/radeon: Remove tests for -ERESTART from the TTM code.

Also sets affected TTM calls up to not wait interruptible, since
that would cause an in-kernel spin until the TTM call succeeds, since
the Radeon code does not return to user-space when a signal is received.

Modifies interruptible fence waits to return -ERESTARTSYS rather than
-EBUSY when interrupted by a signal, since that's the (yet undocumented)
semantics required by the TTM sync object hooks.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index 2ac3163..78743cd 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -197,9 +197,8 @@
 		r = wait_event_interruptible_timeout(rdev->fence_drv.queue,
 				radeon_fence_signaled(fence), timeout);
 		radeon_irq_kms_sw_irq_put(rdev);
-		if (unlikely(r == -ERESTARTSYS)) {
-			return -EBUSY;
-		}
+		if (unlikely(r != 0))
+			return r;
 	} else {
 		radeon_irq_kms_sw_irq_get(rdev);
 		r = wait_event_timeout(rdev->fence_drv.queue,