On 2022/9/20 12:49, Ming Lei wrote: > On Tue, Sep 20, 2022 at 12:39:31PM +0800, Ziyang Zhang wrote: >> On 2022/9/20 12:01, Ming Lei wrote: >>> On Tue, Sep 20, 2022 at 11:24:12AM +0800, Ziyang Zhang wrote: >>>> On 2022/9/20 11:04, Ming Lei wrote: >>>>> On Tue, Sep 20, 2022 at 09:49:33AM +0800, Ziyang Zhang wrote: >>>>> >>>>> Follows the delta patch against patch 5 for showing the idea: >>>>> >>>>> >>>>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c >>>>> index 4409a130d0b6..60c5786c4711 100644 >>>>> --- a/drivers/block/ublk_drv.c >>>>> +++ b/drivers/block/ublk_drv.c >>>>> @@ -656,7 +656,8 @@ static void ublk_complete_rq(struct request *req) >>>>> * Also aborting may not be started yet, keep in mind that one failed >>>>> * request may be issued by block layer again. >>>>> */ >>>>> -static void __ublk_fail_req(struct ublk_io *io, struct request *req) >>>>> +static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io, >>>>> + struct request *req) >>>>> { >>>>> WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE); >>>>> >>>>> @@ -667,7 +668,10 @@ static void __ublk_fail_req(struct ublk_io *io, struct request *req) >>>>> req->tag, >>>>> io->flags); >>>>> io->flags |= UBLK_IO_FLAG_ABORTED; >>>>> - blk_mq_end_request(req, BLK_STS_IOERR); >>>>> + if (ublk_queue_can_use_recovery_reissue(ubq)) >>>>> + blk_mq_requeue_request(req, false); >>>> >>>> Here is one problem: >>>> We reset io->flags to 0 in ublk_queue_reinit() and it is called before new >>> >>> As we agreed, ublk_queue_reinit() will be moved to ublk_ch_release(), when there isn't >>> any inflight request, which is completed by either ublk server or __ublk_fail_req(). >>> >>> So clearing io->flags isn't related with quisceing device. >>> >>>> ubq_daemon with FETCH_REQ is accepted. ublk_abort_queue() is not protected with >>>> ub_mutex and it is called many times in monitor_work. So same rq may be requeued >>>> multiple times. >>> >>> UBLK_IO_FLAG_ABORTED is set for the slot, so one req is only ended or >>> requeued just once. >> >> Yes, we can move ublk_queue_reinit() into ublk_ch_release(), but monitor_work is scheduled >> periodically so ublk_abort_queue() is called multiple times. As ublk_queue_reinit() clear >> io->flags, ublk_abort_queue() can requeue the same rq twice. Note that monitor_work can be >> scheduled after ublk_ch_release(). > > No, monitor work is supposed to be shutdown after in-flight requests are > drained. Let's add cancel_delayed_work_sync(&ub->monitor_work) in ublk_ch_release(). monitor_work should not be scheduled after ub's state is QUIESCED. Regards, Zhang.