Re: [PATCH v12 09/13] arm_mpam: propagate MSC access errors in mpam_reset_class_locked()

[Ben Horgan <ben.horgan@arm.com>]

Hi Andre,

On 01/10/2026 16:34, Andre Przywara wrote:
> The mpam_reset_ris() function can return an error, propagate this up
> through mpam_reset_component_locked() to mpam_reset_class_locked(),
> which is exported. The external caller is a void function, so cannot
> really handle the error at the moment, but at least we report everything
> on the MPAM interface side.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

Reviewed-by: Ben Horgan <ben.horgan@arm.com>

Thanks,

Ben

> ---
>  drivers/resctrl/mpam_devices.c  | 24 ++++++++++++++++++------
>  drivers/resctrl/mpam_internal.h |  2 +-
>  2 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
> index 60f6a39176ea1..c639aaa5f38e1 100644
> --- a/drivers/resctrl/mpam_devices.c
> +++ b/drivers/resctrl/mpam_devices.c
> @@ -3007,7 +3007,7 @@ static void mpam_enable_once(void)
>  	       mpam_partid_max + 1, mpam_pmg_max + 1);
>  }
>  
> -static void mpam_reset_component_locked(struct mpam_component *comp)
> +static int mpam_reset_component_locked(struct mpam_component *comp)
>  {
>  	struct mpam_vmsc *vmsc;
>  
> @@ -3021,26 +3021,38 @@ static void mpam_reset_component_locked(struct mpam_component *comp)
>  				 srcu_read_lock_held(&mpam_srcu)) {
>  		struct mpam_msc *msc = vmsc->msc;
>  		struct mpam_msc_ris *ris;
> +		int ret;
>  
>  		list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list,
>  					 srcu_read_lock_held(&mpam_srcu)) {
> -			if (!ris->in_reset_state)
> -				mpam_touch_msc(msc, mpam_reset_ris, ris);
> +			if (!ris->in_reset_state) {
> +				ret = mpam_touch_msc(msc, mpam_reset_ris, ris);
> +				if (ret)
> +					return ret;
> +			}
>  			ris->in_reset_state = true;
>  		}
>  	}
> +
> +	return 0;
>  }
>  
> -void mpam_reset_class_locked(struct mpam_class *class)
> +int mpam_reset_class_locked(struct mpam_class *class)
>  {
>  	struct mpam_component *comp;
> +	int ret;
>  
>  	lockdep_assert_cpus_held();
>  
>  	guard(srcu)(&mpam_srcu);
>  	list_for_each_entry_srcu(comp, &class->components, class_list,
> -				 srcu_read_lock_held(&mpam_srcu))
> -		mpam_reset_component_locked(comp);
> +				 srcu_read_lock_held(&mpam_srcu)) {
> +		ret = mpam_reset_component_locked(comp);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
>  }
>  
>  static void mpam_reset_class(struct mpam_class *class)
> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
> index 68a6cf2b9cc73..09f8168fb4d2c 100644
> --- a/drivers/resctrl/mpam_internal.h
> +++ b/drivers/resctrl/mpam_internal.h
> @@ -465,7 +465,7 @@ void mpam_enable(struct work_struct *work);
>  void mpam_disable(struct work_struct *work);
>  
>  /* Reset all the RIS in a class under cpus_read_lock() */
> -void mpam_reset_class_locked(struct mpam_class *class);
> +int mpam_reset_class_locked(struct mpam_class *class);
>  
>  int mpam_apply_config(struct mpam_component *comp, u16 partid,
>  		      struct mpam_config *cfg);