include/asm-generic/page.h: calculate virt_to_page and page_to_virt via predefined...

On NOMMU architectures, if physical memory doesn't start from 0,
ARCH_PFN_OFFSET is defined to generate page index in mem_map array.
Because virtual address is equal to physical address, PAGE_OFFSET is
always 0.  virt_to_page and page_to_virt should not index page by
PAGE_OFFSET directly.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/asm-generic/page.h b/include/asm-generic/page.h
index f376db24c4a69d4fea8eda47ff7581bc7b819ee2..37d1fe28960a8ae7d82b2f804008b444c7fde556 100644 (file)
--- a/include/asm-generic/page.h
+++ b/include/asm-generic/page.h
@@ -83,8 +83,8 @@ extern unsigned long memory_end;
 #define virt_to_pfn(kaddr)     (__pa(kaddr) >> PAGE_SHIFT)
 #define pfn_to_virt(pfn)       __va((pfn) << PAGE_SHIFT)
 
-#define virt_to_page(addr)     (mem_map + (((unsigned long)(addr)-PAGE_OFFSET) >> PAGE_SHIFT))
-#define page_to_virt(page)     ((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET)
+#define virt_to_page(addr)     pfn_to_page(virt_to_pfn(addr))
+#define page_to_virt(page)     pfn_to_virt(page_to_pfn(page))
 
 #ifndef page_to_phys
 #define page_to_phys(page)      ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)