Re: [PATCH v9 10/12] fs/resctrl: Call architecture hooks for every mount/unmount

[Reinette Chatre]

Hi Tony,

On 7/1/26 2:35 PM, Tony Luck wrote:
> The intel_pmt module should only be pinned while the resctrl file system
> is mounted.
> 
> Add hooks for every mount/unmount of the resctrl file system so that
> architecture code can increment the intel_pmt module reference count on
> mount and decrement on unmount.
> 
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---

> @@ -3168,6 +3167,8 @@ static void resctrl_unmount(void)
>  	resctrl_mounted = false;
>  	mutex_unlock(&rdtgroup_mutex);
>  	cpus_read_unlock();
> +
> +	resctrl_arch_unmount();
>  }
>  
>  static int rdt_get_tree(struct fs_context *fc)
> @@ -3179,7 +3180,7 @@ static int rdt_get_tree(struct fs_context *fc)
>  	struct rdt_resource *r;
>  	int ret;
>  
> -	DO_ONCE_SLEEPABLE(resctrl_arch_pre_mount);
> +	resctrl_arch_pre_mount();
>  
>  	cpus_read_lock();
>  	mutex_lock(&rdtgroup_mutex);
> @@ -3318,6 +3319,9 @@ static int rdt_get_tree(struct fs_context *fc)
>  out:
>  	mutex_unlock(&rdtgroup_mutex);
>  	cpus_read_unlock();
> +
> +	resctrl_arch_unmount();
> +
>  	return ret;
>  }
>  

rdt_get_tree() jumps to "out" if resctrl is already mounted - in this scenario
resctrl fs is mounted and the telemetry events exposed to user space. Above would
cause telemetry to be yanked from underneath an existing mount?

Reinette