Re: [PATCH v2 09/14] NTB: ntb_transport: Drain RX tasklets during link cleanup

[Dave Jiang]

On 9/9/26 9:08 PM, Koichiro Den wrote:
> ntb_qp_link_cleanup() cancels QP link work but does not wait for the RX
> tasklet. The tasklet can still be processing the ring while cleanup
> resets the QP, and transport link cleanup can free the MW before the
> tasklet finishes.
> 
> Clear active under rx_sched_lock and drain the tasklet before resetting
> the QP. Temporarily disable QP link work so a concurrent client link-up
> request cannot reactivate RX during cleanup, then re-enable it for the
> existing link setup paths.
> 
> This does not drain RX DMA transfers or their completion callbacks.

Is this something that we should handle?

DJ

> 
> Fixes: 9143595a7e05 ("NTB: ntb_transport: Free MWs in ntb_transport_link_cleanup()")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
> ---
> Changes in v2:
>   - No changes.
> 
>  drivers/ntb/ntb_transport.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
> index 45d4365becac..36797ea3ff45 100644
> --- a/drivers/ntb/ntb_transport.c
> +++ b/drivers/ntb/ntb_transport.c
> @@ -956,11 +956,16 @@ static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
>  
>  	dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
>  
> -	cancel_delayed_work_sync(&qp->link_work);
> +	disable_delayed_work_sync(&qp->link_work);
> +	ntb_transport_set_qp_active(qp, false);
> +	tasklet_kill(&qp->rxc_db_work);
> +
>  	ntb_qp_link_down_reset(qp);
>  
>  	if (qp->event_handler)
>  		qp->event_handler(qp->cb_data, qp->link_is_up);
> +
> +	enable_delayed_work(&qp->link_work);
>  }
>  
>  static void ntb_qp_link_cleanup_work(struct work_struct *work)