Commit eb3f1cee authored Jan 14, 2016 by Chen Gang Committed by Mark Salyzyn Mar 30, 2017

UPSTREAM: mm: add PHYS_PFN, use it in __phys_to_pfn()



(cherry pick from commit 8f235d1a3eb7198affe7cadf676a10afb8a46a1a)

__phys_to_pfn and __pfn_to_phys are symmetric, PHYS_PFN and PFN_PHYS are
semmetric:

 - y = (phys_addr_t)x << PAGE_SHIFT

 - y >> PAGE_SHIFT = (phys_add_t)x

 - (unsigned long)(y >> PAGE_SHIFT) = x

[akpm@linux-foundation.org: use macro arg name `x']
[arnd@arndb.de: include linux/pfn.h for PHYS_PFN definition]
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 20045882
Bug: 19198045
Change-Id: If968d2246b381b9e5d6446e9d6d9fa45bb718e91

parent 21accca2

include/asm-generic/memory_model.h

+3 −1

Original line number	Diff line number	Diff line
		#ifndef __ASM_MEMORY_MODEL_H
		#define __ASM_MEMORY_MODEL_H

		#include <linux/pfn.h>

		#ifndef __ASSEMBLY__

		#if defined(CONFIG_FLATMEM)
		@@ -72,7 +74,7 @@
		/*
		* Convert a physical address to a Page Frame Number and back
		*/
		#define __phys_to_pfn(paddr) ((unsigned long)((paddr) >> PAGE_SHIFT))
		#define __phys_to_pfn(paddr) PHYS_PFN(paddr)
		#define __pfn_to_phys(pfn) PFN_PHYS(pfn)

		#define page_to_pfn __page_to_pfn

include/linux/pfn.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -9,5 +9,6 @@
		#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
		#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
		#define PFN_PHYS(x) ((phys_addr_t)(x) << PAGE_SHIFT)
		#define PHYS_PFN(x) ((unsigned long)((x) >> PAGE_SHIFT))

		#endif