Re: [PATCH 07/11] fs/resctrl: Add last_cmd_status support for writes to max_threshold_occupancy

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

Hi Reinette,

On 3/2/26 18:46, Reinette Chatre wrote:
> info/last_cmd_status is intended to contain more information if a write to
> any resctrl file fails. Writes to max_threshold_occupancy did not receive
> last_cmd_status support during initial last_cmd_status enabling. Add it now.

All looks sensible to me.

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

Thanks,

Ben

> 
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
> ---
>  fs/resctrl/rdtgroup.c | 21 ++++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index 3c9508fc558d..933f6ae26d59 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -1238,16 +1238,27 @@ static ssize_t max_threshold_occ_write(struct kernfs_open_file *of,
>  	unsigned int bytes;
>  	int ret;
>  
> +	mutex_lock(&rdtgroup_mutex);
> +	rdt_last_cmd_clear();
> +
>  	ret = kstrtouint(buf, 0, &bytes);
> -	if (ret)
> -		return ret;
> +	if (ret) {
> +		rdt_last_cmd_puts("Invalid input\n");
> +		goto out_unlock;
> +	}
>  
> -	if (bytes > resctrl_rmid_realloc_limit)
> -		return -EINVAL;
> +	if (bytes > resctrl_rmid_realloc_limit) {
> +		rdt_last_cmd_printf("Exceeds limit (before adjustment) of %u bytes\n",
> +				    resctrl_rmid_realloc_limit);
> +		ret = -EINVAL;
> +		goto out_unlock;
> +	}
>  
>  	resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(bytes);
>  
> -	return nbytes;
> +out_unlock:
> +	mutex_unlock(&rdtgroup_mutex);
> +	return ret ?: nbytes;
>  }
>  
>  /*