[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[dm-devel] [PATCH 07/08] dm: proper module reference counting



 Module reference counting appropriately occurs when the block device is
 opened, but dm devices exist outside of the device actually being opened.

 Currently, in certain situations, unloading the dm-mod module will result
 in an oops. This patch claims a reference to the module when a device
 is created, and drops it when the device is freed.

 This is one possible implementation. Another could be to do an internal
 "dmsetup remove_all" when the module is unloaded. Comments welcome.

Signed-off-by: Jeff Mahoney <jeffm suse com>

--
 drivers/md/dm.c |    6 ++++++
 1 files changed, 6 insertions(+)

diff -ruNpX ../dontdiff 2.6.17-rc1-staging1/drivers/md/dm.c 2.6.17-rc1-staging2/drivers/md/dm.c
--- 2.6.17-rc1-staging1/drivers/md/dm.c	2006-04-17 10:51:49.000000000 -0400
+++ 2.6.17-rc1-staging2/drivers/md/dm.c	2006-04-17 10:51:49.000000000 -0400
@@ -846,6 +846,9 @@ 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)
@@ -912,6 +915,8 @@ 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;
 }
@@ -935,6 +940,7 @@ static void free_dev(struct mapped_devic
 
 	put_disk(md->disk);
 	blk_cleanup_queue(md->queue);
+	module_put(THIS_MODULE);
 	kfree(md);
 }
 


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]