1 files changed, 4 insertions, 1 deletions
diff --git a/sys/dev/ciss/ciss.c b/sys/dev/ciss/ciss.c
index 0988b3415d4b2..367d3ceccba39 100644
--- a/sys/dev/ciss/ciss.c
+++ b/sys/dev/ciss/ciss.c
@@ -428,7 +428,10 @@ ciss_detach(device_t dev)
     struct ciss_softc	*sc = device_get_softc(dev);
 
     debug_called(1);
-    
+
+    if (sc->ciss_flags & CISS_FLAG_CONTROL_OPEN)
+	return (EBUSY);
+
     /* flush adapter cache */
     ciss_flush_adapter(sc);