[src/trunk]: src/sys/dev/ata in atabus_detach(), shutdown the channel thread ...

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

details:   https://anonhg.NetBSD.org/src/rev/ed306cb187ab
branches:  trunk
changeset: 446585:ed306cb187ab
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Tue Dec 11 23:06:30 2018 +0000

description:
in atabus_detach(), shutdown the channel thread only after all the
children successfully detach; this is especially important for
atapibus, which needs the thread to execute commands

fixes hang on poweroff with root on ATAPI cd(4), reported by Christoph Badura

diffstat:

 sys/dev/ata/ata.c |  23 ++++++++++++-----------
 1 files changed, 12 insertions(+), 11 deletions(-)

diffs (51 lines):

diff -r dd35678f671f -r ed306cb187ab sys/dev/ata/ata.c
--- a/sys/dev/ata/ata.c Tue Dec 11 23:02:19 2018 +0000
+++ b/sys/dev/ata/ata.c Tue Dec 11 23:06:30 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ata.c,v 1.146 2018/11/12 18:51:01 jdolecek Exp $       */
+/*     $NetBSD: ata.c,v 1.147 2018/12/11 23:06:30 jdolecek Exp $       */
 
 /*
  * Copyright (c) 1998, 2001 Manuel Bouyer.  All rights reserved.
@@ -25,7 +25,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ata.c,v 1.146 2018/11/12 18:51:01 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ata.c,v 1.147 2018/12/11 23:06:30 jdolecek Exp $");
 
 #include "opt_ata.h"
 
@@ -630,15 +630,6 @@
        device_t dev = NULL;
        int i, error = 0;
 
-       /* Shutdown the channel. */
-       ata_channel_lock(chp);
-       chp->ch_flags |= ATACH_SHUTDOWN;
-       while (chp->ch_thread != NULL) {
-               cv_signal(&chp->ch_thr_idle);
-               cv_wait(&chp->ch_thr_idle, &chp->ch_lock);
-       }
-       ata_channel_unlock(chp);
-
        /*
         * Detach atapibus and its children.
         */
@@ -673,6 +664,16 @@
                        KASSERT(chp->ch_drive[i].drive_type == 0);
                }
        }
+
+       /* Shutdown the channel. */
+       ata_channel_lock(chp);
+       chp->ch_flags |= ATACH_SHUTDOWN;
+       while (chp->ch_thread != NULL) {
+               cv_signal(&chp->ch_thr_idle);
+               cv_wait(&chp->ch_thr_idle, &chp->ch_lock);
+       }
+       ata_channel_unlock(chp);
+
        atabus_free_drives(chp);
 
  out: