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Commit 8f235d1a authored by Chen Gang's avatar Chen Gang Committed by Linus Torvalds
Browse files

mm: add PHYS_PFN, use it in __phys_to_pfn() 



__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: default avatarChen Gang <gang.chen.5i5j@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3aa23851

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