details: https://anonhg.NetBSD.org/src/rev/9d98c7c78365
branches: trunk
changeset: 810185:9d98c7c78365
user: mlelstv <mlelstv%NetBSD.org@localhost>
date: Thu Aug 20 23:08:33 2015 +0000
description:
when scanning for disklabels, close block device only when this was
the first open. The device driver doesn't do reference counting.
This is still subject to race conditions.
diffstat:
sys/dev/dkwedge/dk.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
diffs (50 lines):
diff -r fb9ed87b4df1 -r 9d98c7c78365 sys/dev/dkwedge/dk.c
--- a/sys/dev/dkwedge/dk.c Thu Aug 20 22:27:49 2015 +0000
+++ b/sys/dev/dkwedge/dk.c Thu Aug 20 23:08:33 2015 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: dk.c,v 1.79 2015/01/02 01:14:22 christos Exp $ */
+/* $NetBSD: dk.c,v 1.80 2015/08/20 23:08:33 mlelstv Exp $ */
/*-
* Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.79 2015/01/02 01:14:22 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.80 2015/08/20 23:08:33 mlelstv Exp $");
#ifdef _KERNEL_OPT
#include "opt_dkwedge.h"
@@ -944,7 +944,7 @@
void *tbuf, size_t len)
{
buf_t *bp;
- int error;
+ int error, isopen;
/*
* The kernel cannot read from a character device vnode
@@ -964,6 +964,12 @@
bp->b_cylinder = 0;
bp->b_error = 0;
+ /*
+ * XXX Only the last user of a block device can close it.
+ * There is no reference counting in the driver.
+ */
+ isopen = pdk->dk_bopenmask & (1 << DISKPART(bp->b_dev));
+
error = bdev_open(bp->b_dev, FREAD, S_IFBLK, curlwp);
if (error)
return error;
@@ -972,7 +978,8 @@
error = biowait(bp);
putiobuf(bp);
- bdev_close(bp->b_dev, FREAD, S_IFBLK, curlwp);
+ if (!isopen)
+ bdev_close(bp->b_dev, FREAD, S_IFBLK, curlwp);
return error;
}