On Mon, Jul 22, 2019 at 9:27 AM Bart Van Assche <bvanass...@acm.org> wrote:
> On 7/21/19 10:39 PM, Ming Lei wrote:
> > Before aborting in-flight requests, all IO queues have been shutdown.
> > However, request's completion fn may not be done yet because it may
> > be scheduled to run via IPI.
> >
> > So don't abort one request if it is marked as completed, otherwise
> > we may abort one normal completed request.
> >
> > Cc: Max Gurtovoy <m...@mellanox.com>
> > Cc: Sagi Grimberg <s...@grimberg.me>
> > Cc: Keith Busch <keith.bu...@intel.com>
> > Cc: Christoph Hellwig <h...@lst.de>
> > Signed-off-by: Ming Lei <ming....@redhat.com>
> > ---
> > drivers/nvme/host/core.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> > index cc09b81fc7f4..cb8007cce4d1 100644
> > --- a/drivers/nvme/host/core.c
> > +++ b/drivers/nvme/host/core.c
> > @@ -285,6 +285,10 @@ EXPORT_SYMBOL_GPL(nvme_complete_rq);
> >
> > bool nvme_cancel_request(struct request *req, void *data, bool reserved)
> > {
> > + /* don't abort one completed request */
> > + if (blk_mq_request_completed(req))
> > + return;
> > +
> > dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
> > "Cancelling I/O %d", req->tag);
>
> Something I probably already asked before: what prevents that
> nvme_cancel_request() is executed concurrently with the completion
> handler of the same request?
At least for pci, we've shutdown the queues and their interrupts prior
to tagset iteration, so we can't concurrently execute a natural
completion for in-flight requests while cancelling them.
