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

From: Laura Abbott
Date: Sat Jan 19 2019 - 11:50:49 EST

On 1/19/19 2:25 AM, Christoph Hellwig wrote:
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

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.

I'm not sure having flags in dma-buf really solves anything
given drivers can use the attributes directly with dma_map
anyway, which is what we're looking to do. The intention
is for the driver creating the dma_buf attachment to have
the knowledge of which flags to use.