Re: [PATCH 1/2] uio: introduce UIO_MEM_DMA_COHERENT type

[Christoph Hellwig <hch@lst.de>]

On Wed, Jan 31, 2024 at 01:44:50PM -0800, Chris Leech wrote:
> On Wed, Jan 31, 2024 at 1:29 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Wed, Jan 31, 2024 at 11:17:31AM -0800, Chris Leech wrote:
> > > Add a UIO memtype specifically for sharing dma_alloc_coherent
> > > memory with userspace, backed by dma_mmap_coherent.
> > >
> > > This is mainly for the bnx2/bnx2x/bnx2i "cnic" interface, although there
> > > are a few other uio drivers which map dma_alloc_coherent memory and
> > > could be converted to use dma_mmap_coherent as well.
> >
> > What other drivers could use this?  Patches doing the conversion would
> > be welcome, otherwise, again, I am very loath to take this
> > one-off-change for just a single driver that shouldn't be doing this in
> > the first place :)
> 
> uio_pruss and uio_dmem_genirq both appear to mmap dma_alloc_coherent
> memory as UIO_MEM_PHYS.  It might not be an issue on that platforms
> where those are used, but I'd be happy to include untested patches to
> convert them for better adherence to the DMA APIs.

Yes, they do need fixing.