[PATCH v2] nvme-fc: fix racing controller reset and create association

[Ewan D. Milne]

On Mon, 2021-03-08 at 16:51 -0800, James Smart wrote:
> Recent patch to prevent calling __nvme_fc_abort_outstanding_ios in
> interrupt context results in a possible race condition. A controller
> reset results in errored io completions, which schedules error
> work. The change of error work to a work element allows it to fire
> after the ctrl state transition to NVME_CTRL_CONNECTING, causing
> any outstanding io (used to initialize the controller) to fail and
> cause problems for connect_work.
> 
> Add a state check to only schedule error work if not in the RESETTING
> state.
> 
> Fixes: 19fce0470f05 ("nvme-fc: avoid calling
> _nvme_fc_abort_outstanding_ios from interrupt context")
> Cc: <stable at vger.kernel.org> # v5.10+
> 
> Signed-off-by: Nigel Kirkland <nkirkland2304 at gmail.com>
> Signed-off-by: James Smart <jsmart2021 at gmail.com>
> 
> ---
> v2: clean up typo in commit header
> ---
>  drivers/nvme/host/fc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 20dadd86e981..0f92bd12123e 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2055,7 +2055,7 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
>  		nvme_fc_complete_rq(rq);
>  
>  check_error:
> -	if (terminate_assoc)
> +	if (terminate_assoc && ctrl->ctrl.state != NVME_CTRL_RESETTING)
>  		queue_work(nvme_reset_wq, &ctrl->ioerr_work);
>  }
>  

This fix resolves the frequent -EBUSY / -ENETRESET errors I saw when
resetting the controller via sysfs, as well as the eventual hang with
the controller stuck in the _CONNECTING state, thanks.  Looks good.

-Ewan