Re: [PATCH V5 9/9] null_blk: serialize configfs attribute shows with the file-scope lock

[Bart Van Assche]

On 7/13/26 9:18 PM, Zizhi Wo wrote:
> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
> index 67cd32d28887..c8487a630e1a 100644
> --- a/drivers/block/null_blk/main.c
> +++ b/drivers/block/null_blk/main.c
> @@ -345,8 +345,14 @@ static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
>   static ssize_t								\
>   nullb_device_##NAME##_show(struct config_item *item, char *page)	\
>   {									\
> -	return nullb_device_##TYPE##_attr_show(				\
> +	ssize_t ret;							\
> +									\
> +	mutex_lock(&lock);						\
> +	ret = nullb_device_##TYPE##_attr_show(				\
>   				to_nullb_device(item)->NAME, page);	\
> +	mutex_unlock(&lock);						\
> +									\
> +	return ret;							\
>   }									\
>   static ssize_t								\
>   nullb_device_##NAME##_store(struct config_item *item, const char *page,	\
> @@ -479,7 +485,13 @@ NULLB_DEVICE_ATTR(badblocks_partial_io, bool, NULL);
>   
>   static ssize_t nullb_device_power_show(struct config_item *item, char *page)
>   {
> -	return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
> +	ssize_t ret;
> +
> +	mutex_lock(&lock);
> +	ret = nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
> +	mutex_unlock(&lock);
> +
> +	return ret;
>   }

The above changes would be much more elegant if guard()() would be used 
instead of explicit mutex_lock() and mutex_unlock() calls.

Thanks,

Bart.