From 8f235d1a3eb7198affe7cadf676a10afb8a46a1a Mon Sep 17 00:00:00 2001 From: Chen Gang Date: Thu, 14 Jan 2016 15:18:33 -0800 Subject: 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: Chen Gang Cc: Oleg Nesterov Signed-off-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pfn.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/pfn.h') diff --git a/include/linux/pfn.h b/include/linux/pfn.h index 7646637221f3..97f3e88aead4 100644 --- a/include/linux/pfn.h +++ b/include/linux/pfn.h @@ -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 -- cgit v1.2.3