Re: [PATCH v2 01/10] arch: introduce __pfn_t for persistent memory i/o
On Thu, May 7, 2015 at 7:55 AM, Stephen Rothwell <sfr(a)canb.auug.org.au> wrote:
Hi Dan,
On Wed, 06 May 2015 16:04:59 -0400 Dan Williams <dan.j.williams(a)intel.com> wrote:
>
> diff --git a/include/asm-generic/pfn.h b/include/asm-generic/pfn.h
> new file mode 100644
> index 000000000000..91171e0285d9
> --- /dev/null
> +++ b/include/asm-generic/pfn.h
> @@ -0,0 +1,51 @@
> +#ifndef __ASM_PFN_H
> +#define __ASM_PFN_H
> +
> +#ifndef __pfn_to_phys
> +#define __pfn_to_phys(pfn) ((dma_addr_t)(pfn) << PAGE_SHIFT)
Why dma_addr_t and not phys_addr_t? i.e. it could use a comment if it
is correct.
Hmm, this was derived from:
#define page_to_phys(page) ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
in arch/x86/include/asm/io.h
The primary users of __pfn_to_phys() is dma_map_page(). I'll add a
comment to that effect.