merge do_mremap() into sys_mremap()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

mm/mremap.c

@@ -432,15 +432,17 @@ static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
  * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
  * This option implies MREMAP_MAYMOVE.
  */
-unsigned long do_mremap(unsigned long addr,
-	unsigned long old_len, unsigned long new_len,
-	unsigned long flags, unsigned long new_addr)
+SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
+		unsigned long, new_len, unsigned long, flags,
+		unsigned long, new_addr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned long ret = -EINVAL;
 	unsigned long charged = 0;
 
+	down_write(&current->mm->mmap_sem);
+
 	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
 		goto out;
 
@@ -538,17 +540,6 @@ unsigned long do_mremap(unsigned long addr,
 out:
 	if (ret & ~PAGE_MASK)
 		vm_unacct_memory(charged);
-	return ret;
-}
-
-SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
-		unsigned long, new_len, unsigned long, flags,
-		unsigned long, new_addr)
-{
-	unsigned long ret;
-
-	down_write(&current->mm->mmap_sem);
-	ret = do_mremap(addr, old_len, new_len, flags, new_addr);
 	up_write(&current->mm->mmap_sem);
 	return ret;
 }