Re: [PATCH v2 12/12] arm_mpam: resctrl: Don't stop early when tearing down a class

[Jinjie Ruan <ruanjinjie@huawei.com>]

在 2026/9/17 22:56, Ben Horgan 写道:
> An MPAM class can back more than one control and more than one
> monitor. mpam_resctrl_teardown_class() iterates through all the controls
> but stops if it finds a match which means classes backing more than one
> class aren't torn down. The same for monitors, in which case the mbwu
> counters will be leaked.
> 
> Stop terminating the loops early.
> 
> As we are already changing mpam_resctrl_teardown_class() remove the
> misleading comment. It doesn't call resctrl_exit() and isn't required to do
> so as the only caller does it first.
> 
> Fixes: fb481ec08699 ("arm_mpam: resctrl: Call resctrl_init() on platforms that can support resctrl")
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
> ---
> Changes since v1:
> 
> New patch
> ---
>  drivers/resctrl/mpam_resctrl.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
> index 321741a702fe..9cec5843e8fa 100644
> --- a/drivers/resctrl/mpam_resctrl.c
> +++ b/drivers/resctrl/mpam_resctrl.c
> @@ -1943,10 +1943,6 @@ static void mpam_resctrl_teardown_mon(struct mpam_resctrl_mon *mon, struct mpam_
>  	mon->mbwu_idx_to_mon = NULL;
>  }
>  
> -/*
> - * The driver is detaching an MSC from this class, if resctrl was using it,
> - * pull on resctrl_exit().
> - */
>  void mpam_resctrl_teardown_class(struct mpam_class *class)
>  {
>  	struct mpam_resctrl_res *res;
> @@ -1957,17 +1953,14 @@ void mpam_resctrl_teardown_class(struct mpam_class *class)
>  	might_sleep();
>  
>  	for_each_mpam_resctrl_control(res, rid) {
> -		if (res->class == class) {
> +		if (res->class == class)
>  			res->class = NULL;
> -			break;
> -		}
>  	}
>  	for_each_mpam_resctrl_mon(mon, eventid) {
>  		if (mon->class == class) {
>  			mon->class = NULL;
>  
>  			mpam_resctrl_teardown_mon(mon, class);

My LLM also found this problem.

LGTM
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>

> -			break;
>  		}
>  	}
>  }

-- 
Best regards,
Jinjie