On Mon, 11 Feb 2019 12:16:24 -0800
Andrew Morton <a...@linux-foundation.org> wrote:
> On Mon, 11 Feb 2019 17:06:46 +0100 Jesper Dangaard Brouer <bro...@redhat.com>
> wrote:
>
> > The page_pool API is using page->private to store DMA addresses.
> > As pointed out by David Miller we can't use that on 32-bit architectures
> > with 64-bit DMA
> >
> > This patch adds a new dma_addr_t struct to allow storing DMA addresses
> >
> > ..
> >
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -95,6 +95,14 @@ struct page {
> > */
> > unsigned long private;
> > };
> > + struct { /* page_pool used by netstack */
> > + /**
> > + * @dma_addr: Page_pool need to store DMA-addr, and
> > + * cannot use @private, as DMA-mappings can be 64-bit
> > + * even on 32-bit Architectures.
> > + */
>
> This comment is a bit awkward. The discussion about why it doesn't use
> ->private is uninteresting going forward and is more material for a
> changelog.
>
> How about
>
> /**
> * @dma_addr: page_pool requires a 64-bit value even on
> * 32-bit architectures.
> */
Much better, I'll use that!
> Otherwise,
>
> Acked-by: Andrew Morton <a...@linux-foundation.org>
Thanks!
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
