On Thu, 11 Aug 2011, James Bottomley wrote: > > If the reason you moved scsi_free_queue into scsi_remove_device > > is marking the queue dead, how about the following patch? > > Do you think it's acceptable? > > Well, it's just hiding the problem. The essential problem is that only > block has the correctly refcounted knowledge to know the last release of > the queue reference. Until that time, the holder of the reference can > use the queue regardless of whether blk_cleanup_queue() has been called. > This is the race you complain about since use of the queue involves the > lock which should be guarded by QUEUE_DEAD checks. > > This is essentially unfixable with function calls. The only way to fix > it is to have a callback model for freeing the external lock. Assuming the queue is associated with a device, the queue could take a reference to the device, dropping that reference when the queue is freed. Then the lock could safely be freed at the same time as the device. Alan Stern -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
