Hi Greg, Thanks for comments. Greg KH wrote:
+/* This is a mere directory in sysfs. No methods are needed. */ +static struct kobj_type bd_holder_ktype = { + .release = NULL, + .sysfs_ops = NULL, + .default_attrs = NULL, +};That doesn't look right. You always need a release function.
I'll move them out to gendisk/hd_struct creation with proper release function. I thought it's correct because NULL release function is just ignored in kobject_cleanup() and it let outside function to release the whole structure. But it seems wrong to embed these additional kobjects in the structures which are logically separate from them.
+static inline void del_holder_dir(struct block_device *bdev) +{ + /* + * Don't kobject_unregister to avoid memory allocation + * in kobject_hotplug. + */ + kobject_del(&bdev->bd_holder_dir); + kobject_put(&bdev->bd_holder_dir); +}No, do it correctly please.
OK, I'll change them to kobject_unregister() and do it when gendisk/hd_struct is removed. Then we can avoid possible memory allocation in dm's atomic operation, too. -- Jun'ichi Nomura, NEC Solutions (America), Inc. -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
