drm/i915: Convert i915_wait_seqno to i915_wait_request

Updated i915_wait_seqno() to take a request structure instead of a seqno value
and renamed it accordingly. Internally, it just pulls the seqno out of the
request and calls on to __wait_seqno() as before. However, all the code further
up the stack is now simplified as it can just pass the request object straight
through without having to peek inside.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Squash in hunk from an earlier patch which was rebased
wrongly.]
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 accfc89..b9d0d29 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1899,7 +1899,6 @@
 {
 	struct intel_ringbuffer *ringbuf = ring->buffer;
 	struct drm_i915_gem_request *request;
-	u32 seqno = 0;
 	int ret;
 
 	if (ringbuf->last_retired_head != -1) {
@@ -1914,15 +1913,14 @@
 	list_for_each_entry(request, &ring->request_list, list) {
 		if (__intel_ring_space(request->tail, ringbuf->tail,
 				       ringbuf->size) >= n) {
-			seqno = request->seqno;
 			break;
 		}
 	}
 
-	if (seqno == 0)
+	if (&request->list == &ring->request_list)
 		return -ENOSPC;
 
-	ret = i915_wait_seqno(ring, seqno);
+	ret = i915_wait_request(request);
 	if (ret)
 		return ret;
 
@@ -2011,7 +2009,7 @@
 
 int intel_ring_idle(struct intel_engine_cs *ring)
 {
-	u32 seqno;
+	struct drm_i915_gem_request *req;
 	int ret;
 
 	/* We need to add any requests required to flush the objects and ring */
@@ -2025,11 +2023,11 @@
 	if (list_empty(&ring->request_list))
 		return 0;
 
-	seqno = list_entry(ring->request_list.prev,
+	req = list_entry(ring->request_list.prev,
 			   struct drm_i915_gem_request,
-			   list)->seqno;
+			   list);
 
-	return i915_wait_seqno(ring, seqno);
+	return i915_wait_request(req);
 }
 
 static int