What does the c2h do?

I have a question regarding the concurrency of a C2H accelerated function. If a function is basically doing just a memory transfer and C2H acceleration is performed on it, will the hardware version of the function still block code execution while the memory transfer is occurring? I would think it would have to since in sequential C code there may be subsequent functions which expect the transfer to be complete. Where as if the code was written to use DMA, the subsequent functions would wait until the DMA done flag was set. So can C2H be used to improve memory transfer functions, or is DMA required since the rest of the code must be aware of transfer completion?