On Tue, Dec 05, 2017 at 01:13:43AM +0000, Bart Van Assche wrote: > On Tue, 2017-12-05 at 09:04 +0800, Ming Lei wrote: > > Then no reason to revert commit(0df21c86bdbf scsi: implement .get_budget an > > .put_budget for blk-mq) for one issue which may never happen in reality since > > this reproducer need out-of-tree patch. > > Sorry but I disagree completely. You seem to overlook that there may be other > circumstances that trigger the same lockup, e.g. a SCSI queue full condition. If the scsi_dev_queue_ready() returns false, .get_budget() catches that and never add request to hctx->dispatch. And scsi_host_queue_ready() always returns true, since we respect per-host queue depth by blk_mq_get_driver_tag() before calling .queue_rq(). Or if I miss other cases, please point it out. -- Ming
