fs/proc/task_mmu.c: update m->version in the main loop in m_start()

Change the main loop in m_start() to update m->version. Mostly for
consistency, but this can help to avoid the same loop if the very
1st ->show() fails due to seq_overflow().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/task_mmu.c

@@ -184,11 +184,14 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
 
 	m->version = 0;
 	if (pos < mm->map_count) {
-		for (vma = mm->mmap; pos; pos--)
+		for (vma = mm->mmap; pos; pos--) {
+			m->version = vma->vm_start;
 			vma = vma->vm_next;
+		}
 		return vma;
 	}
 
+	/* we do not bother to update m->version in this case */
 	if (pos == mm->map_count && priv->tail_vma)
 		return priv->tail_vma;