lkml.org 
[lkml]   [2006]   [May]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 8/10] dm: add module ref counting
From: Jeff Mahoney <jeffm@suse.com>

The reference counting on dm-mod is zero if no mapped devices are
open. This is incorrect, and can lead to an oops if the module
is unloaded while mapped devices exist.

This patch claims a reference to the module whenever a device is
created, and drops it again when the device is freed.

Devices must be removed before dm-mod is unloaded.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-Off-By: Alasdair G Kergon <agk@redhat.com>

Index: linux-2.6.17-rc4/drivers/md/dm.c
===================================================================
--- linux-2.6.17-rc4.orig/drivers/md/dm.c 2006-05-23 18:18:25.000000000 +0100
+++ linux-2.6.17-rc4/drivers/md/dm.c 2006-05-23 19:37:14.000000000 +0100
@@ -852,6 +852,9 @@ static struct mapped_device *alloc_dev(u
return NULL;
}

+ if (!try_module_get(THIS_MODULE))
+ goto bad0;
+
/* get a minor number for the dev */
r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
if (r < 0)
@@ -918,6 +921,8 @@ static struct mapped_device *alloc_dev(u
blk_cleanup_queue(md->queue);
free_minor(minor);
bad1:
+ module_put(THIS_MODULE);
+ bad0:
kfree(md);
return NULL;
}
@@ -941,6 +946,7 @@ static void free_dev(struct mapped_devic

put_disk(md->disk);
blk_cleanup_queue(md->queue);
+ module_put(THIS_MODULE);
kfree(md);
}

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2006-05-25 21:21    [W:0.050 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site