Re: [PATCH v3] usb: core: sysfs: convert sysfs snprintf to sysfs_emit

[Joe Perches <joe@perches.com>]

On Fri, 2022-06-24 at 20:12 +0800, Xuezhi Zhang wrote:
> Fix up all sysfs show entries to use sysfs_emit

Thanks.

Some trivia: (perhaps for a separate patch)

> diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
[]
> @@ -35,7 +35,7 @@ static ssize_t field##_show(struct device *dev,				\
>  		return -EINTR;						\
>  	actconfig = udev->actconfig;					\
>  	if (actconfig)							\
> -		rc = sprintf(buf, format_string,			\
> +		rc = sysfs_emit(buf, format_string,			\
>  				actconfig->desc.field);			\

It's much more common to use fmt and not format_string

Using fmt would make several multi-line statements fit on a single line

e.g.:

		rc = sysfs_emit(buf, fmt, actconfig->desc.field);	\

> @@ -305,8 +305,8 @@ static ssize_t ltm_capable_show(struct device *dev,
>  				struct device_attribute *attr, char *buf)
>  {
>  	if (usb_device_supports_ltm(to_usb_device(dev)))
> -		return sprintf(buf, "%s\n", "yes");
> -	return sprintf(buf, "%s\n", "no");
> +		return sysfs_emit(buf, "%s\n", "yes");
> +	return sysfs_emit(buf, "%s\n", "no");

Using a ?: might be nicer

	return sysfs_emit(buf, "%s\n",
			  usb_device_supports_ltm(to_usb_device(dev)) ? "yes" : "no");

>  static ssize_t persist_store(struct device *dev, struct device_attribute *attr,
> @@ -372,7 +372,7 @@ static ssize_t connected_duration_show(struct device *dev,
>  {
>  	struct usb_device *udev = to_usb_device(dev);
>  
> -	return sprintf(buf, "%u\n",
> +	return sysfs_emit(buf, "%u\n",
>  			jiffies_to_msecs(jiffies - udev->connect_time));

Might be nicer to rewrap multi-line statements to the open parenthesis

	return sysfs_emit(buf, "%u\n",
			  jiffies_to_msecs(jiffies - udev->connect_time));