Re: [PATCH 7/8] nvme: use blk_mq_queue_tag_busy_iter

[James Smart]

On 3/15/2019 9:33 AM, James Smart wrote:
> On 3/15/2019 1:57 AM, Jianchao Wang wrote:
> > blk_mq_tagset_busy_iter is not safe that it could get stale request
> > in tags->rqs[]. Use blk_mq_queue_tag_busy_iter here. A new helper
> > interface nvme_iterate_inflight_rqs is introduced to iterate
> > all of the ns under a ctrl.
> >
> > Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
> > ---
> > Â drivers/nvme/host/core.cÂÂ | 12 ++++++++++++
> > Â drivers/nvme/host/fc.cÂÂÂÂ | 12 ++++++------
> > Â drivers/nvme/host/nvme.hÂÂ |Â 2 ++
> > Â drivers/nvme/host/pci.cÂÂÂ |Â 5 +++--
> > Â drivers/nvme/host/rdma.cÂÂ |Â 6 +++---
> > Â drivers/nvme/host/tcp.cÂÂÂ |Â 5 +++--
> > Â drivers/nvme/target/loop.c |Â 6 +++---
> > Â 7 files changed, 32 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> > index 6a9dd68..5760fad 100644
> > --- a/drivers/nvme/host/core.c
> > +++ b/drivers/nvme/host/core.c
> > @@ -3816,6 +3816,18 @@ void nvme_start_queues(struct nvme_ctrl *ctrl)
> > Â }
> > Â EXPORT_SYMBOL_GPL(nvme_start_queues);
> > Â +void nvme_iterate_inflight_rqs(struct nvme_ctrl *ctrl,
> > +ÂÂÂÂÂÂÂ busy_iter_fn *fn, void *data)
> > +{
> > +ÂÂÂ struct nvme_ns *ns;
> > +
> > +ÂÂÂ down_read(&ctrl->namespaces_rwsem);
> > +ÂÂÂ list_for_each_entry(ns, &ctrl->namespaces, list)
> > +ÂÂÂÂÂÂÂ blk_mq_queue_tag_busy_iter(ns->queue, fn, data, true);
> > +ÂÂÂ up_read(&ctrl->namespaces_rwsem);
> > +}
> > +EXPORT_SYMBOL_GPL(nvme_iterate_inflight_rqs);
>
> Hmm... so this aborts ios for namespaces. How about ios that aren't 
> for a namespace but rather for the controller itself. For example, 
> anything on the admin queue ?ÂÂ Rather critical for those ios be 
> terminated as well.
NVM - didn't look at which tag set. but it does highlight - doesn't 
cover anything issued by core/transport on the io queues.

-- james