drm/nouveau/bo: add helper functions for handling pinned+mapped buffers

This is a common, awkward sequence.  Let's wrap it up!
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bo.h

@@ -105,4 +105,32 @@ nvbo_kmap_obj_iovirtual(struct nouveau_bo *nvbo)
 	return ioptr;
 }
 
+static inline void
+nouveau_bo_unmap_unpin_unref(struct nouveau_bo **pnvbo)
+{
+	if (*pnvbo) {
+		nouveau_bo_unmap(*pnvbo);
+		nouveau_bo_unpin(*pnvbo);
+		nouveau_bo_ref(NULL, pnvbo);
+	}
+}
+
+static inline int
+nouveau_bo_new_pin_map(struct nouveau_cli *cli, u64 size, int align, u32 flags,
+		       struct nouveau_bo **pnvbo)
+{
+	int ret = nouveau_bo_new(cli, size, align, flags,
+				 0, 0, NULL, NULL, pnvbo);
+	if (ret == 0) {
+		ret = nouveau_bo_pin(*pnvbo, flags, true);
+		if (ret == 0) {
+			ret = nouveau_bo_map(*pnvbo);
+			if (ret == 0)
+				return ret;
+			nouveau_bo_unpin(*pnvbo);
+		}
+		nouveau_bo_ref(NULL, pnvbo);
+	}
+	return ret;
+}
 #endif