The reason patch got rejected is super simple: because this wrapper not lives in specific driver and depends on DMA subsystem internal API.
And this cause problem. When someone make any change to Linux kernel they suppose to fix all the code they break across all kernel. And if said wrapper accepted then maintaner of DMA will have to make sure that all patches he accepts also fix Rust parts.
And this cause problem. When someone make any change to Linux kernel they suppose to fix all the code they break across all kernel. And if said wrapper accepted then maintaner of DMA will have to make sure that all patches he accepts also fix Rust parts.
So he just dont want extra burden for himself.