mm/mmap: 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: Alexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mmap.c

@@ -1302,7 +1302,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 	 * that it represents a valid section of the address space.
 	 */
 	addr = get_unmapped_area(file, addr, len, pgoff, flags);
-	if (addr & ~PAGE_MASK)
+	if (offset_in_page(addr))
 		return addr;
 
 	/* Do simple checking here so the lower-level routines won't have
@@ -1473,7 +1473,7 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
 
 	if (copy_from_user(&a, arg, sizeof(a)))
 		return -EFAULT;
-	if (a.offset & ~PAGE_MASK)
+	if (offset_in_page(a.offset))
 		return -EINVAL;
 
 	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
@@ -1989,7 +1989,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	 * can happen with large stack limits and large mmap()
 	 * allocations.
 	 */
-	if (addr & ~PAGE_MASK) {
+	if (offset_in_page(addr)) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
 		info.low_limit = TASK_UNMAPPED_BASE;
@@ -2025,7 +2025,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 
 	if (addr > TASK_SIZE - len)
 		return -ENOMEM;
-	if (addr & ~PAGE_MASK)
+	if (offset_in_page(addr))
 		return -EINVAL;
 
 	addr = arch_rebalance_pgtables(addr, len);
@@ -2535,7 +2535,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
 	unsigned long end;
 	struct vm_area_struct *vma, *prev, *last;
 
-	if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
+	if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
 		return -EINVAL;
 
 	len = PAGE_ALIGN(len);
@@ -2733,7 +2733,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
 	flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
 
 	error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
-	if (error & ~PAGE_MASK)
+	if (offset_in_page(error))
 		return error;
 
 	error = mlock_future_check(mm, mm->def_flags, len);