Re: [PATCH v14 5/5] x86/sgx: Enable automatic SVN updates for SGX enclaves

[Dave Hansen]

On 8/14/25 00:34, Elena Reshetova wrote:
> +/* Mutex to ensure no concurrent EPC accesses during EUPDATESVN */
> +static DEFINE_MUTEX(sgx_svn_lock);
> +
>  int sgx_inc_usage_count(void)
>  {
> +	int ret;
> +
> +	guard(mutex)(&sgx_svn_lock);
> +
> +	if (!sgx_usage_count) {
> +		ret = sgx_update_svn();
> +		if (ret)
> +			return ret;
> +	}
> +
> +	sgx_usage_count++;
> +
>  	return 0;
>  }
>  
>  void sgx_dec_usage_count(void)
>  {
> -	return;
> +	sgx_usage_count--;
>  }

How is a plain int-- safe?

Where's the locking?