Re: [PATCH v3 10/16] block/mq-deadline: Improve the sysfs show and store macros

[Adam Manzanares <a.manzanares@samsung.com>]

On Thu, Jun 17, 2021 at 05:44:50PM -0700, Bart Van Assche wrote:
> Define separate macros for integers and jiffies to improve readability.
> Use sysfs_emit() and kstrtoint() instead of sprintf() and simple_strtol().
> The former functions are the recommended functions.
> 
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  block/mq-deadline.c | 66 ++++++++++++++++++++-------------------------
>  1 file changed, 29 insertions(+), 37 deletions(-)
> 
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index 69126beff77d..f92224ff0256 100644
> --- a/block/mq-deadline.c
> +++ b/block/mq-deadline.c
> @@ -605,58 +605,50 @@ static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
>  /*
>   * sysfs parts below
>   */
> -static ssize_t
> -deadline_var_show(int var, char *page)
> -{
> -	return sprintf(page, "%d\n", var);
> -}
> -
> -static void
> -deadline_var_store(int *var, const char *page)
> -{
> -	char *p = (char *) page;
> -
> -	*var = simple_strtol(p, &p, 10);
> -}
> -
> -#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
> +#define SHOW_INT(__FUNC, __VAR)						\
>  static ssize_t __FUNC(struct elevator_queue *e, char *page)		\
>  {									\
>  	struct deadline_data *dd = e->elevator_data;			\
> -	int __data = __VAR;						\
> -	if (__CONV)							\
> -		__data = jiffies_to_msecs(__data);			\
> -	return deadline_var_show(__data, (page));			\
> -}
> -SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[DD_READ], 1);
> -SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[DD_WRITE], 1);
> -SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
> -SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
> -SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
> -#undef SHOW_FUNCTION
> +									\
> +	return sysfs_emit(page, "%d\n", __VAR);				\
> +}
> +#define SHOW_JIFFIES(__FUNC, __VAR) SHOW_INT(__FUNC, jiffies_to_msecs(__VAR))
> +SHOW_JIFFIES(deadline_read_expire_show, dd->fifo_expire[DD_READ]);
> +SHOW_JIFFIES(deadline_write_expire_show, dd->fifo_expire[DD_WRITE]);
> +SHOW_INT(deadline_writes_starved_show, dd->writes_starved);
> +SHOW_INT(deadline_front_merges_show, dd->front_merges);
> +SHOW_INT(deadline_fifo_batch_show, dd->fifo_batch);
> +#undef SHOW_INT
> +#undef SHOW_JIFFIES
>  
>  #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
>  static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
>  {									\
>  	struct deadline_data *dd = e->elevator_data;			\
> -	int __data;							\
> -	deadline_var_store(&__data, (page));				\
> +	int __data, __ret;						\
> +									\
> +	__ret = kstrtoint(page, 0, &__data);				\
> +	if (__ret < 0)							\
> +		return __ret;						\
>  	if (__data < (MIN))						\
>  		__data = (MIN);						\
>  	else if (__data > (MAX))					\
>  		__data = (MAX);						\
> -	if (__CONV)							\
> -		*(__PTR) = msecs_to_jiffies(__data);			\
> -	else								\
> -		*(__PTR) = __data;					\
> +	*(__PTR) = __CONV(__data);					\
>  	return count;							\
>  }
> -STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX, 1);
> -STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX, 1);
> -STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
> -STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
> -STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
> +#define STORE_INT(__FUNC, __PTR, MIN, MAX)				\
> +	STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, )
> +#define STORE_JIFFIES(__FUNC, __PTR, MIN, MAX)				\
> +	STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, msecs_to_jiffies)
> +STORE_JIFFIES(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX);
> +STORE_JIFFIES(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX);
> +STORE_INT(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX);
> +STORE_INT(deadline_front_merges_store, &dd->front_merges, 0, 1);
> +STORE_INT(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX);
>  #undef STORE_FUNCTION
> +#undef STORE_INT
> +#undef STORE_JIFFIES
>  
>  #define DD_ATTR(name) \
>  	__ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)

Looks good.

Reviewed by: Adam Manzanares <a.manzanares@samsung.com>