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authorJames Bottomley <JBottomley@Parallels.com>2013-11-15 14:58:00 -0800
committerJames Bottomley <JBottomley@Parallels.com>2013-12-02 11:13:14 -0800
commita1470c7bf3a4676e62e4c0fb204e339399eb5c59 (patch)
tree5678d07f70cadae7509067b2118a956400d41ff8 /drivers/misc/enclosure.c
parent6cd60b37f72b2d15b8983431546af50b7064935d (diff)
downloadlinux-a1470c7bf3a4676e62e4c0fb204e339399eb5c59.tar.gz
[SCSI] enclosure: fix WARN_ON in dual path device removing
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
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/misc/enclosure.c')
-rw-r--r--drivers/misc/enclosure.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
index 0e8df41aaf14..2cf2bbc0b927 100644
--- a/drivers/misc/enclosure.c
+++ b/drivers/misc/enclosure.c
@@ -198,6 +198,13 @@ static void enclosure_remove_links(struct enclosure_component *cdev)
 {
 	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");