[src/trunk]: src/sys/dev Get out of cgd_detach() early on error. Do not call...

[dyoung <dyoung%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4835b70719d6
branches:  trunk
changeset: 750988:4835b70719d6
user:      dyoung <dyoung%NetBSD.org@localhost>
date:      Wed Jan 20 18:55:17 2010 +0000

description:
Get out of cgd_detach() early on error.  Do not call disk_destroy(9)
on error, that leaves the cgd_softc in an inconsistent state.

Fixes a crash during shutdown reported by Patrick Welche.  Thanks
to Patrick for reporting and for testing the fix.

diffstat:

 sys/dev/cgd.c |  28 +++++++++++++---------------
 1 files changed, 13 insertions(+), 15 deletions(-)

diffs (53 lines):

diff -r 08fbf3d9340e -r 4835b70719d6 sys/dev/cgd.c
--- a/sys/dev/cgd.c     Wed Jan 20 18:13:40 2010 +0000
+++ b/sys/dev/cgd.c     Wed Jan 20 18:55:17 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgd.c,v 1.66 2010/01/12 23:49:34 dyoung Exp $ */
+/* $NetBSD: cgd.c,v 1.67 2010/01/20 18:55:17 dyoung Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.66 2010/01/12 23:49:34 dyoung Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.67 2010/01/20 18:55:17 dyoung Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -193,23 +193,21 @@
 static int
 cgd_detach(device_t self, int flags)
 {
-       int     ret = 0;
-       int     pmask = 1 << RAW_PART;
+       int ret;
+       const int pmask = 1 << RAW_PART;
        struct cgd_softc *sc = device_private(self);
-       struct dk_softc *dksc;
+       struct dk_softc *dksc = &sc->sc_dksc;
+
+       if (DK_BUSY(dksc, pmask))
+               return EBUSY;
 
-       dksc = &sc->sc_dksc;
-       if ((dksc->sc_flags & DKF_INITED) != 0)
-       {
-               if (DK_BUSY(&sc->sc_dksc, pmask))
-                       ret = EBUSY;
-               else
-                       ret = cgd_ioctl_clr(sc, curlwp);
-       }
+       if ((dksc->sc_flags & DKF_INITED) != 0 &&
+           (ret = cgd_ioctl_clr(sc, curlwp)) != 0)
+               return ret;
 
-       disk_destroy(&sc->sc_dksc.sc_dkdev);
+       disk_destroy(&dksc->sc_dkdev);
 
-       return ret;
+       return 0;
 }
 
 void