Re: [PATCH v2] ice: wait for reset completion in ice_resume()

[Kohei Enju <kohei@enjuk.jp>]

On 04/24 11:03, Aaron Ma wrote:
> ice_resume() schedules an asynchronous PF reset and returns
> immediately. The reset runs later in ice_service_task(). If
> userspace tries to bring up the net device before the reset
> finishes, ice_open() fails with -EBUSY:
> 
>   ice_resume()
>     ice_schedule_reset()          # sets ICE_PFR_REQ, returns
>   ...
>   ice_open()
>     ice_is_reset_in_progress()    # ICE_PFR_REQ still set, -EBUSY
>   ...
>   ice_service_task()
>     ice_do_reset()
>       ice_rebuild()               # clears ICE_PFR_REQ, too late
> 
> Reproduced on E800 series NICs during suspend/resume with irdma
> enabled, where the aux device probe widens the race window.
> 
> Wait for the reset to complete before returning from ice_resume().
> 
> Fixes: 769c500dcc1e ("ice: Add advanced power mgmt for WoL")
> Cc: stable@vger.kernel.org
> Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
> ---
> v2: reword comment to clarify best-effort semantics (Kohei Enju)
> 
>  drivers/net/ethernet/intel/ice/ice_main.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index 5f92377d4dfc2..a81eb21ea87c1 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -5635,6 +5635,15 @@ static int ice_resume(struct device *dev)
>  	/* Restart the service task */
>  	mod_timer(&pf->serv_tmr, round_jiffies(jiffies + pf->serv_tmr_period));
>  
> +	/* Best-effort wait for the scheduled reset to finish so that the
> +	 * device is operational before returning. Without this, userspace
> +	 * (e.g. NetworkManager) may try to open the net device while the
> +	 * asynchronous reset is still in progress, hitting -EBUSY.
> +	 */

Thanks for the update!

Reviewed-by: Kohei Enju <kohei@enjuk.jp>

> +	ret = ice_wait_for_reset(pf, 10 * HZ);
> +	if (ret)
> +		dev_err(dev, "Wait for reset failed during resume: %d\n", ret);
> +
>  	return 0;
>  }
>  
> -- 
> 2.43.0
>