Re: [PATCH iwl-net v5] ice: fix missing dpll notifications for SW pins

[Michal Schmidt <mschmidt@redhat.com>]

On 4/9/26 12:25, Petr Oros wrote:
> ---
>   drivers/net/ethernet/intel/ice/ice_dpll.c | 74 +++++++++++++++++++----
>   1 file changed, 63 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
> index 3f8cd5b8298b57..d817f17dcf1951 100644
> --- a/drivers/net/ethernet/intel/ice/ice_dpll.c
> +++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
> @@ -1154,6 +1154,30 @@ ice_dpll_input_state_get(const struct dpll_pin *pin, void *pin_priv,
>   				      extack, ICE_DPLL_PIN_TYPE_INPUT);
>   }
>   
> +/**
> + * ice_dpll_sw_pin_notify_peer - notify the paired SW pin after a state change
> + * @d: pointer to dplls struct
> + * @changed: the SW pin that was explicitly changed (already notified by dpll core)
> + *
> + * SMA and U.FL pins share physical signal paths in pairs (SMA1/U.FL1 and
> + * SMA2/U.FL2).  When one pin's routing changes via the PCA9575 GPIO
> + * expander, the paired pin's state may also change.  Send a change
> + * notification for the peer pin so userspace consumers monitoring the
> + * peer via dpll netlink learn about the update.
> + *
> + * Context: Can be called under pf->dplls.lock, dpll_pin_change_ntf() is safe.
> + */
> +static void ice_dpll_sw_pin_notify_peer(struct ice_dplls *d,
> +					struct ice_dpll_pin *changed)
> +{
> +	struct ice_dpll_pin *peer;
> +
> +	peer = (changed >= d->sma && changed < d->sma + ICE_DPLL_PIN_SW_NUM) ?
> +		&d->ufl[changed->idx] : &d->sma[changed->idx];
> +	if (peer->pin)
> +		dpll_pin_change_ntf(peer->pin);
> +}
> +
>   /**
>    * ice_dpll_sma_direction_set - set direction of SMA pin
>    * @p: pointer to a pin
> @@ -1233,6 +1257,8 @@ static int ice_dpll_sma_direction_set(struct ice_dpll_pin *p,
>   			ret = ice_dpll_pin_state_update(p->pf, target,
>   							type, extack);
>   	}
> +	if (!ret)
> +		ice_dpll_sw_pin_notify_peer(d, p);
>   
>   	return ret;
>   }

ice_dpll_sma_direction_set() runs to process a DPLL_CMD_PIN_SET command 
from userspace. It runs with dpll_lock held - taken in dpll_pin_pre_doit().
ice_dpll_sw_pin_notify_peer() -> dpll_pin_change_ntf() will take 
dpll_lock again and deadlock.

Michal