[PATCH] md: fix ref-counting problems with kobjects in md

Thanks Greg.

Cc:  Greg KH <greg@kroah.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 7 insertions, 3 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index e58d61d9f31b..fe0137a5b002 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -805,7 +805,11 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
                         if (fixdesc & (1<<rdev2->desc_nr)) {
                                 snprintf(rdev2->kobj.name, KOBJ_NAME_LEN, "dev%d",
                                          rdev2->desc_nr);
+                                /* kobject_add gets a ref on the parent, so
+                                 * we have to drop the one we already have
+                                 */
                                 kobject_add(&rdev2->kobj);
+                                kobject_put(rdev->kobj.parent);
                                 sysfs_create_link(&rdev2->kobj,
                                                   &rdev2->bdev->bd_disk->kobj,
                                                   "block");
@@ -1178,7 +1182,7 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 
         rdev->kobj.k_name = NULL;
         snprintf(rdev->kobj.name, KOBJ_NAME_LEN, "dev%d", rdev->desc_nr);
-        rdev->kobj.parent = kobject_get(&mddev->kobj);
+        rdev->kobj.parent = &mddev->kobj;
         kobject_add(&rdev->kobj);
 
         sysfs_create_link(&rdev->kobj, &rdev->bdev->bd_disk->kobj, "block");
@@ -1864,7 +1868,7 @@ static struct kobject *md_probe(dev_t dev, int *part, void *data)
         add_disk(disk);
         mddev->gendisk = disk;
         up(&disks_sem);
-        mddev->kobj.parent = kobject_get(&disk->kobj);
+        mddev->kobj.parent = &disk->kobj;
         mddev->kobj.k_name = NULL;
         snprintf(mddev->kobj.name, KOBJ_NAME_LEN, "%s", "md");
         mddev->kobj.ktype = &md_ktype;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 061d265ed94e..246c9b1cc4a3 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1975,7 +1975,7 @@ memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
         }
 
         /* Ok, everything is just fine now */
-        conf->kobj.parent = kobject_get(&mddev->kobj);
+        conf->kobj.parent = &mddev->kobj;
         strcpy(conf->kobj.name, "raid5");
         conf->kobj.ktype = &raid5_ktype;
         kobject_register(&conf->kobj);