Re: [PATCH 3/4] dma-buf: add support for mapping with dma mapping attributes

[Christoph Hellwig]

On Fri, Jan 18, 2019 at 10:37:46AM -0800, Liam Mark wrote:
> Add support for configuring dma mapping attributes when mapping
> and unmapping memory through dma_buf_map_attachment and
> dma_buf_unmap_attachment.
> 
> Signed-off-by: Liam Mark <lmark@xxxxxxxxxxxxxx>

And who is going to decide which ones to pass?  And who documents
which ones are safe?

I'd much rather have explicit, well documented dma-buf flags that
might get translated to the DMA API flags, which are not error checked,
not very well documented and way to easy to get wrong.