[src/trunk]: src/sys/kern devsw(9): Forbid extant linked autoconf instances i...

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

details:   https://anonhg.NetBSD.org/src/rev/427b9d2c2e79
branches:  trunk
changeset: 368392:427b9d2c2e79
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Jul 09 10:30:27 2022 +0000

description:
devsw(9): Forbid extant linked autoconf instances in devsw_detach.

diffstat:

 sys/kern/subr_devsw.c |  31 ++++++++++++++++++++++++++++---
 1 files changed, 28 insertions(+), 3 deletions(-)

diffs (55 lines):

diff -r 1e4960ee7692 -r 427b9d2c2e79 sys/kern/subr_devsw.c
--- a/sys/kern/subr_devsw.c     Sat Jul 09 09:43:51 2022 +0000
+++ b/sys/kern/subr_devsw.c     Sat Jul 09 10:30:27 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_devsw.c,v 1.45 2022/03/28 12:41:17 riastradh Exp $        */
+/*     $NetBSD: subr_devsw.c,v 1.46 2022/07/09 10:30:27 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2001, 2002, 2007, 2008 The NetBSD Foundation, Inc.
@@ -69,7 +69,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.45 2022/03/28 12:41:17 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.46 2022/07/09 10:30:27 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_dtrace.h"
@@ -372,10 +372,35 @@
 static void
 devsw_detach_locked(const struct bdevsw *bdev, const struct cdevsw *cdev)
 {
-       int bi, ci = -1/*XXXGCC*/;
+       int bi, ci = -1/*XXXGCC*/, di;
+       struct cfdriver *cd;
+       device_t dv;
 
        KASSERT(mutex_owned(&device_lock));
 
+       /*
+        * If this is wired to an autoconf device, make sure the device
+        * has no more instances.  No locking here because under
+        * correct use of devsw_detach, none of this state can change
+        * at this point.
+        */
+       if (cdev != NULL && (cd = cdev->d_cfdriver) != NULL) {
+               for (di = 0; di < cd->cd_ndevs; di++) {
+                       KASSERTMSG((dv = cd->cd_devs[di]) == NULL,
+                           "detaching character device driver %s"
+                           " still has attached unit %s",
+                           cd->cd_name, device_xname(dv));
+               }
+       }
+       if (bdev != NULL && (cd = bdev->d_cfdriver) != NULL) {
+               for (di = 0; di < cd->cd_ndevs; di++) {
+                       KASSERTMSG((dv = cd->cd_devs[di]) == NULL,
+                           "detaching block device driver %s"
+                           " still has attached unit %s",
+                           cd->cd_name, device_xname(dv));
+               }
+       }
+
        /* Prevent new references.  */
        if (bdev != NULL) {
                for (bi = 0; bi < max_bdevsws; bi++) {