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@samsung.com 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.