Re: [PATCH net-next] net: bridge: use sysfs_emit instead of sprintf

[Ido Schimmel <idosch@nvidia.com>]

On Sat, Jan 31, 2026 at 04:53:09PM +0000, David Corvaglia wrote:
> Replace sprintf with sysfs_emit in sysfs show() methods as outlined in
> Documentation/filesystems/sysfs.rst. sysfs_emit is preferred to sprintf 
> in sysfs show() methods as it is safer with buffer handling.
> 
> Signed-off-by: David Corvaglia <david@corvaglia.dev>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

But the patch is introducing a few alignment issues and it would be good
to fix them in v2. See below.

[...]

> @@ -87,7 +87,7 @@ static DEVICE_ATTR_RW(forward_delay);
>  static ssize_t hello_time_show(struct device *d, struct device_attribute *attr,
>  			       char *buf)
>  {
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(to_bridge(d)->hello_time));

Here

>  }
>  
> @@ -108,7 +108,7 @@ static DEVICE_ATTR_RW(hello_time);
>  static ssize_t max_age_show(struct device *d, struct device_attribute *attr,
>  			    char *buf)
>  {
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(to_bridge(d)->max_age));

Here

>  }
>  

[...]

>  static int set_group_fwd_mask(struct net_bridge *br, unsigned long val,
> @@ -200,7 +200,7 @@ static ssize_t priority_show(struct device *d, struct device_attribute *attr,
>  			     char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%d\n",
> +	return sysfs_emit(buf, "%d\n",
>  		       (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]);

Here

>  }

[...]

> @@ -425,7 +425,7 @@ static ssize_t multicast_query_use_ifaddr_show(struct device *d,
>  					       char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%d\n",
> +	return sysfs_emit(buf, "%d\n",
>  		       br_opt_get(br, BROPT_MULTICAST_QUERY_USE_IFADDR));

Here

>  }

> @@ -583,7 +583,7 @@ static ssize_t multicast_last_member_interval_show(
>  	struct device *d, struct device_attribute *attr, char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(br->multicast_ctx.multicast_last_member_interval));

Here

>  }
>  
> @@ -606,7 +606,7 @@ static ssize_t multicast_membership_interval_show(
>  	struct device *d, struct device_attribute *attr, char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(br->multicast_ctx.multicast_membership_interval));

Here

>  }
>  
> @@ -630,7 +630,7 @@ static ssize_t multicast_querier_interval_show(struct device *d,
>  					       char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(br->multicast_ctx.multicast_querier_interval));

Here

>  }
>  
> @@ -654,7 +654,7 @@ static ssize_t multicast_query_interval_show(struct device *d,
>  					     char *buf)
>  {
>  	struct net_bridge *br = to_bridge(d);
> -	return sprintf(buf, "%lu\n",
> +	return sysfs_emit(buf, "%lu\n",
>  		       jiffies_to_clock_t(br->multicast_ctx.multicast_query_interval));

Here

>  }

[...]

> @@ -727,7 +727,7 @@ static ssize_t multicast_stats_enabled_show(struct device *d,
>  {
>  	struct net_bridge *br = to_bridge(d);
>  
> -	return sprintf(buf, "%d\n",
> +	return sysfs_emit(buf, "%d\n",
>  		       br_opt_get(br, BROPT_MULTICAST_STATS_ENABLED));

Here

>  }