mm: add PHYS_PFN, use it in __phys_to_pfn() (8f235d1a) · Commits · 戴 / test

__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>

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

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