drm/i915: Update alloc_request to return the allocated request

The alloc_request() function does not actually return the newly allocated
request. Instead, it must be pulled from ring->outstanding_lazy_request. This
patch fixes this so that code can create a request and start using it knowing
exactly which request it actually owns.

v2: Updated for new i915_gem_request_alloc() scheme.

For: VIZ-5115
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Tomas Elf <tomas.elf@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index b48aea1..13eab17 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2277,6 +2277,7 @@
 int intel_ring_begin(struct intel_engine_cs *ring,
 		     int num_dwords)
 {
+	struct drm_i915_gem_request *req;
 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
 	int ret;
 
@@ -2290,7 +2291,7 @@
 		return ret;
 
 	/* Preallocate the olr before touching the ring */
-	ret = i915_gem_request_alloc(ring, ring->default_context);
+	ret = i915_gem_request_alloc(ring, ring->default_context, &req);
 	if (ret)
 		return ret;