* sub_alloc - try to allocate an id without growing the tree depth
* @idp: idr handle
* @starting_id: id to start search at
- * @id: pointer to the allocated handle
* @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer
* @gfp_mask: allocation mask for idr_layer_alloc()
* @layer_idr: optional idr passed to idr_layer_alloc()