On Fri, Oct 14, 2011 at 04:57:30PM -0700, Andrew Morton wrote: > On Thu, 06 Oct 2011 15:54:46 +0200 > Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > +#ifdef phys_to_pfn > > +/* nothing to do */ > > +#elif defined __phys_to_pfn > > +# define phys_to_pfn __phys_to_pfn > > +#elif defined __va > > +# define phys_to_pfn(x) page_to_pfn(virt_to_page(__va(x))) > > +#else > > +# error phys_to_pfn implementation needed > > +#endif > > Yikes! > > This hackery should not be here, please. If we need a phys_to_pfn() > then let's write a proper one which lives in core MM and arch, then get > it suitably reviewed and integrated and then maintained. Another question is whether we have any arch where PFN != PHYS >> PAGE_SHIFT? We've used __phys_to_pfn() to implement that on ARM (with a corresponding __pfn_to_phys()). Catalin recently added a cast to __phys_to_pfn() for LPAE, which I don't think is required: -#define __phys_to_pfn(paddr) ((paddr) >> PAGE_SHIFT) +#define __phys_to_pfn(paddr) ((unsigned long)((paddr) >> PAGE_SHIFT)) since a phys_addr_t >> PAGE_SHIFT will be silently truncated if the passed in physical address was 64-bit anyway. (Note: we don't support > 32-bit PFNs). So, I'd suggest CMA should just use PFN_DOWN() and be done with it. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>