[PATCH 3.2 114/185] [SCSI] enclosure: fix WARN_ON in dual path device removing

Ben Hutchings
2013-12-29T02:39:39Z

From: James Bottomley <JBottomley@Parallels.com>

commit a1470c7bf3a4676e62e4c0fb204e339399eb5c59 upstream.

Bug report from: wenxiong@linux.vnet.ibm.com

The issue is happened in dual controller configuration. We got the
sysfs warnings when rmmod the ipr module.

enclosure_unregister() in drivers/msic/enclosure.c, call device_unregister()
for each componment deivce, device_unregister() ->device_del()->kobject_del()
->sysfs_remove_dir(). In sysfs_remove_dir(), set kobj->sd = NULL.

For each componment device,
enclosure_component_release()->enclosure_remove_links()->sysfs_remove_link()
in which checking kobj->sd again, it has been set as NULL when doing
device_unregister. So we saw all these sysfs WARNING.

Tested-by: wenxiong@linux.vnet.ibm.com
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/misc/enclosure.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/drivers/misc/enclosure.c
+++ b/drivers/misc/enclosure.c
@@ -198,6 +198,13 @@ static void enclosure_remove_links(struc
{
char name[ENCLOSURE_NAME_SIZE];

+ /*
+ * In odd circumstances, like multipath devices, something else may
+ * already have removed the links, so check for this condition first.
+ */
+ if (!cdev->dev->kobj.sd)
+ return;
+
enclosure_link_name(cdev, name);
sysfs_remove_link(&cdev->dev->kobj, name);
sysfs_remove_link(&cdev->cdev.kobj, "device");