diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 5d91262..93718e5 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -64,6 +64,12 @@
 	return (s->size - 1) - s->len;
 }
 
+/* How much buffer was written? */
+static inline unsigned int seq_buf_used(struct seq_buf *s)
+{
+	return min(s->len, s->size);
+}
+
 extern __printf(2, 3)
 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
 extern __printf(2, 0)