Re: [PATCH] nvme: bump genctr when cancelling a request

[Keith Busch <kbusch@kernel.org>]

On Sun, Sep 13, 2026 at 12:41:01PM +0000, Mateusz Nowicki wrote:
> The cancel path is taken when the host stopped waiting for the
> controller: CSTS.CFS set (dead path in nvme_dev_disable(), no CC.EN=0,
> no wait), or CSTS.RDY not cleared within CAP.TO. Nothing stops the
> controller from posting completions after that, and the second
> nvme_dev_disable() from nvme_reset_work() reaps them in
> nvme_reap_pending_cqes().

I think it was supposed to be that we don't cancel a request while it's
still possible to see a natural completion. So with that in mind,
perhaps the call to "nvme_disable_ctrl" should be called unconditionally
instead of only on a live controller.

The sequence you're describing is weird, though. Your controller
has fatal status, the driver hasn't done anything yet to recover the
device, so why were there no completions available the first go around,
then completions became available on the second? The controller
shouldn't have done anything in that time, nor should it have been able
to since Bus Master Enable was off.