On Wed, 2007-10-31 at 12:44 -0400, Alan Stern wrote: > On Wed, 31 Oct 2007, James Bottomley wrote: > > > OK, light beginning to go on now. > > > > The problem is that you've fallen into the conceptual trap we tried very > > hard to avoid in the initial go around of joining SCSI upper layer > > drivers to gendisks. That's why no gendisk references are held by the > > mid-layer, only by the entities that represent the objects created by > > upper layer drivers. > > > > Doesn't this circularity now exist for everything? Every device that > > creates a queue has a reference to the queue, every queue has a > > reference to its attached gendisk and now every gendisk has a reference > > to the device creating the queue? This doesn't look to be a SCSI > > specific problem. > > It probably isn't. I haven't looked at other subsystems but the > scenario you described could well be the common case. > > Dropping a kobject's reference to its parent when the kobject is > removed rather than when it is deleted will solve all these problems. > The queue's reference to the gendisk and the gendisk's reference to the > device will both be dropped when the device is unregistered, allowing > the device and gendisk to be released. When the device is released it > can then drop its reference to the queue, allowing the queue to be > released. > > In other words, reverting that 4-year-old patch would fix everything. > I'd still like to get your acknowledgement for my patch, posted here: > > http://marc.info/?l=linux-scsi&m=119368368904151&w=2 It sounds plausible, but I'm not really up to speed on all the changes going on in sysfs at the moment, so it would be dangerous to rely on what I think sounds reasonable. James - 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
