diff --git a/[refs] b/[refs]
index 385e86b32008..a37b6271c0ce 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f2e62992a232544d612b7b95e932fbf3592944e1
+refs/heads/master: d9f9d31983aac7764d178583d0777199d081cb1a
diff --git a/trunk/arch/um/kernel/sigio.c b/trunk/arch/um/kernel/sigio.c
index 2b0ab438301c..1c831f9ee09f 100644
--- a/trunk/arch/um/kernel/sigio.c
+++ b/trunk/arch/um/kernel/sigio.c
@@ -42,6 +42,7 @@ int write_sigio_irq(int fd)
 	return(0);
 }
 
+/* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
 static DEFINE_SPINLOCK(sigio_spinlock);
 
 void sigio_lock(void)