mm/msync: use offset_in_page macro

linux/mm.h provides offset_in_page() macro.  Let's use already predefined
macro instead of (addr & ~PAGE_MASK).
Signed-off-by: NAlexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/msync.c

@@ -38,7 +38,7 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 
 	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
 		goto out;
-	if (start & ~PAGE_MASK)
+	if (offset_in_page(start))
 		goto out;
 	if ((flags & MS_ASYNC) && (flags & MS_SYNC))
 		goto out;