drm/v3d: Use drm_gem_lock_reservations()/drm_gem_unlock_reservations()

Now that we have core helpers, this gets rid of a lot of boilerplate.
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190308161716.2466-3-eric@anholt.netAcked-by: Rob Herring <robh@kernel.org>

drivers/gpu/drm/v3d/v3d_gem.c

@@ -210,12 +210,8 @@ v3d_unlock_bo_reservations(struct v3d_bo **bos,
 			   int bo_count,
 			   struct ww_acquire_ctx *acquire_ctx)
 {
-	int i;
-
-	for (i = 0; i < bo_count; i++)
-		ww_mutex_unlock(&bos[i]->base.resv->lock);
-
-	ww_acquire_fini(acquire_ctx);
+	drm_gem_unlock_reservations((struct drm_gem_object **)bos, bo_count,
+				    acquire_ctx);
 }
 
 /* Takes the reservation lock on all the BOs being referenced, so that
@@ -230,52 +226,12 @@ v3d_lock_bo_reservations(struct v3d_bo **bos,
 			 int bo_count,
 			 struct ww_acquire_ctx *acquire_ctx)
 {
-	int contended_lock = -1;
 	int i, ret;
 
-	ww_acquire_init(acquire_ctx, &reservation_ww_class);
-
-retry:
-	if (contended_lock != -1) {
-		struct v3d_bo *bo = bos[contended_lock];
-
-		ret = ww_mutex_lock_slow_interruptible(&bo->base.resv->lock,
-						       acquire_ctx);
-		if (ret) {
-			ww_acquire_done(acquire_ctx);
-			return ret;
-		}
-	}
-
-	for (i = 0; i < bo_count; i++) {
-		if (i == contended_lock)
-			continue;
-
-		ret = ww_mutex_lock_interruptible(&bos[i]->base.resv->lock,
-						  acquire_ctx);
-		if (ret) {
-			int j;
-
-			for (j = 0; j < i; j++)
-				ww_mutex_unlock(&bos[j]->base.resv->lock);
-
-			if (contended_lock != -1 && contended_lock >= i) {
-				struct v3d_bo *bo = bos[contended_lock];
-
-				ww_mutex_unlock(&bo->base.resv->lock);
-			}
-
-			if (ret == -EDEADLK) {
-				contended_lock = i;
-				goto retry;
-			}
-
-			ww_acquire_done(acquire_ctx);
+	ret = drm_gem_lock_reservations((struct drm_gem_object **)bos,
+					bo_count, acquire_ctx);
+	if (ret)
 		return ret;
-		}
-	}
-
-	ww_acquire_done(acquire_ctx);
 
 	/* Reserve space for our shared (read-only) fence references,
 	 * before we commit the CL to the hardware.