[dm-devel] [patch 168/215] dm: add module ref counting
akpm at osdl.org
akpm at osdl.org
Fri Nov 24 03:24:52 UTC 2006
From: Jeff Mahoney <jeffm at 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.
[akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled]
Signed-off-by: Jeff Mahoney <jeffm at suse.com>
Signed-off-by: Alasdair G Kergon <agk at redhat.com>
Signed-off-by: Andrew Morton <akpm at osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
---
drivers/md/dm.c | 6 ++++++
1 file changed, 6 insertions(+)
--- linux-2.6.17.11.orig/drivers/md/dm.c
+++ linux-2.6.17.11/drivers/md/dm.c
@@ -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);
}
--WIyZ46R2i8wDzkSu
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Content-Disposition: attachment; filename="dm-mirror-sector-offset-fix.patch"
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