On Wed, 31 Oct 2007, James Bottomley wrote: > > Yes, the queue is a child of the disk. > > Right, so this goes gendisk->queue (-> meaning parent of, or takes > reference to) No, no! The _child_ takes an implicit reference to the _parent_, not the other way around. > > > The scsi_device has a ref to the queue > > > > Yeah, while the queue is a grandchild of the scsi_device with the > > unified sysfs layout. > > No, the scsi_device is a direct parent of the queue, so we have > > scsi_device->queue Wrong -- the gendisk is the direct parent of the queue. The relevant line is in ll_rw_blk.c:blk_register_queue(): q->kobj.parent = kobject_get(&disk->dev.kobj); > > Yes, sounds right. We need to break that deleted-but-wait-for-cleanup at > > least at one of the devices involved. > > But it's broken when the driver is unbound. Diagrammatically it's: > > scsi_disk -> scsi_device -> queue > -> gendisk -> > > It's not circular, it's released when scsi_disk is released. It can > become circular if there's some hidden dependency between any of the > components ... but I don't think there is. Forget about the scsi_disk. It isn't part of the problem. Just concentrate on the scsi_device, the gendisk, and the queue. We have: scsi_device <- gendisk <- queue <- scsi_device, where "A <- B" means that B holds a reference to A. Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
