RE: [RFC PATCH] dmadev: offload to free source buffer

[Amit Prakash Shukla <amitprakashs@marvell.com>]

> > > >
> > > > No. DMA hardware would determine the pointer to the mbuf using
> > > > iova address and mempool. Hardware will free the buffer, on
> > > > completion of
> > > data transfer.
> > >
> > > OK. If there are any requirements to the mempool, it needs to be
> > > documented in the source code comments. E.g. does it work with
> > > mempools where the mempool driver is an MP_RTS/MC_RTS ring, or a
> stack?
> >
> > I think adding a comment, related to type of supported mempool, in dma
> > library code might not be needed as it is driver implementation dependent.
> > Call to dev->dev_ops->vchan_setup for the driver shall check and
> > return error for unsupported type of mempool.
> 
> Makes sense. But I still think that it needs to be mentioned that
> RTE_DMA_CAPA_MEM_TO_DEV_SOURCE_BUFFER_FREE has some
> limitations, and doesn't mean that any type of mempool can be used.
> 
> I suggest you add a note to the description of the new "struct rte_mempool
> *mem_to_dev_src_buf_pool" field in the rte_dma_vchan_conf structure,
> such as:
> 
> Note: If the mempool is not supported by the DMA driver,
> rte_dma_vchan_setup() will fail.
> 
> You should also mention it with the description of
> RTE_DMA_CAPA_MEM_TO_DEV_SOURCE_BUFFER_FREE flag, such as:
> 
> Note: Even though the DMA driver has this capability, it may not support all
> mempool drivers. If the mempool is not supported by the DMA driver,
> rte_dma_vchan_setup() will fail.

Sure, I will add a note in next version of the patch.

Thanks.