linux-kernel - Re: [PATCH 1/2] fbcon: Register sysfs groups through device_add

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Message-ID: <f6011b3e-97f1-8ead-b9a8-933a015c59ad@163.com>
Date: Thu, 13 Mar 2025 20:24:51 +0800
From: Shixiong Ou <oushixiong1025@....com>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Cc: Simona Vetter <simona@...ll.ch>, Helge Deller <deller@....de>,
 Thomas Zimmermann <tzimmermann@...e.de>,
 Samuel Thibault <samuel.thibault@...-lyon.org>,
 Zsolt Kajtar <soci@....rulez.org>, linux-fbdev@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 Shixiong Ou <oushixiong@...inos.cn>
Subject: Re: [PATCH 1/2] fbcon: Register sysfs groups through device_add_group


在 2025/3/13 00:47, Thomas Weißschuh 写道:
> Hi,
>
> On Tue, Mar 11, 2025 at 07:28:55PM +0800, oushixiong1025@....com wrote:
>> From: Shixiong Ou <oushixiong@...inos.cn>
>>
>> Use device_add_group() to simplify creation and removal.
>>
>> Signed-off-by: Shixiong Ou <oushixiong@...inos.cn>
>> ---
>>   drivers/video/fbdev/core/fbcon.c | 48 +++++++++++++++-----------------
>>   1 file changed, 22 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
>> index 07d127110ca4..51c3e8a5a092 100644
>> --- a/drivers/video/fbdev/core/fbcon.c
>> +++ b/drivers/video/fbdev/core/fbcon.c
>> @@ -3159,7 +3159,7 @@ static const struct consw fb_con = {
>>   	.con_debug_leave	= fbcon_debug_leave,
>>   };
>>   
>> -static ssize_t store_rotate(struct device *device,
>> +static ssize_t rotate_store(struct device *device,
>>   			    struct device_attribute *attr, const char *buf,
>>   			    size_t count)
>>   {
>> @@ -3181,7 +3181,7 @@ static ssize_t store_rotate(struct device *device,
>>   	return count;
>>   }
>>   
>> -static ssize_t store_rotate_all(struct device *device,
>> +static ssize_t rotate_all_store(struct device *device,
>>   				struct device_attribute *attr,const char *buf,
>>   				size_t count)
>>   {
>> @@ -3203,7 +3203,7 @@ static ssize_t store_rotate_all(struct device *device,
>>   	return count;
>>   }
>>   
>> -static ssize_t show_rotate(struct device *device,
>> +static ssize_t rotate_show(struct device *device,
>>   			   struct device_attribute *attr,char *buf)
>>   {
>>   	struct fb_info *info;
>> @@ -3222,7 +3222,7 @@ static ssize_t show_rotate(struct device *device,
>>   	return sysfs_emit(buf, "%d\n", rotate);
>>   }
>>   
>> -static ssize_t show_cursor_blink(struct device *device,
>> +static ssize_t cursor_blink_show(struct device *device,
>>   				 struct device_attribute *attr, char *buf)
>>   {
>>   	struct fb_info *info;
>> @@ -3247,7 +3247,7 @@ static ssize_t show_cursor_blink(struct device *device,
>>   	return sysfs_emit(buf, "%d\n", blink);
>>   }
>>   
>> -static ssize_t store_cursor_blink(struct device *device,
>> +static ssize_t cursor_blink_store(struct device *device,
>>   				  struct device_attribute *attr,
>>   				  const char *buf, size_t count)
>>   {
>> @@ -3281,32 +3281,30 @@ static ssize_t store_cursor_blink(struct device *device,
>>   	return count;
>>   }
>>   
>> -static struct device_attribute device_attrs[] = {
>> -	__ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
>> -	__ATTR(rotate_all, S_IWUSR, NULL, store_rotate_all),
>> -	__ATTR(cursor_blink, S_IRUGO|S_IWUSR, show_cursor_blink,
>> -	       store_cursor_blink),
>> +static DEVICE_ATTR_RW(rotate);
>> +static DEVICE_ATTR_WO(rotate_all);
>> +static DEVICE_ATTR_RW(cursor_blink);
>> +
>> +static struct attribute *fbcon_device_attrs[] = {
>> +	&dev_attr_rotate.attr,
>> +	&dev_attr_rotate_all.attr,
>> +	&dev_attr_cursor_blink.attr,
>> +	NULL,
> No trailing commas after sentinel values.
>
>> +};
>> +
>> +static const struct attribute_group fbcon_device_attr_group = {
>> +	.attrs		= fbcon_device_attrs,
>>   };
>>   
>>   static int fbcon_init_device(void)
>>   {
>> -	int i, error = 0;
>> +	int ret;
>>   
>>   	fbcon_has_sysfs = 1;
>>   
>> -	for (i = 0; i < ARRAY_SIZE(device_attrs); i++) {
>> -		error = device_create_file(fbcon_device, &device_attrs[i]);
>> -
>> -		if (error)
>> -			break;
>> -	}
>> -
>> -	if (error) {
>> -		while (--i >= 0)
>> -			device_remove_file(fbcon_device, &device_attrs[i]);
>> -
>> +	ret = device_add_group(fbcon_device, &fbcon_device_attr_group);
>> +	if (ret)
>>   		fbcon_has_sysfs = 0;
>> -	}
>>   
>>   	return 0;
>>   }
>> @@ -3389,11 +3387,9 @@ void __init fb_console_init(void)
>>   
>>   static void __exit fbcon_deinit_device(void)
>>   {
>> -	int i;
>>   
>>   	if (fbcon_has_sysfs) {
>> -		for (i = 0; i < ARRAY_SIZE(device_attrs); i++)
>> -			device_remove_file(fbcon_device, &device_attrs[i]);
>> +		device_remove_group(fb_info->dev, &fbcon_device_attr_group);
> Please at least compile-test your changes before submission.
>
>>   
>>   		fbcon_has_sysfs = 0;
>>   	}
> All of this can be simplified even more:
>
> * fbcon_deinit_device() can be removed easily, as the attributes are
>    automatically removed when the device is destroyed.
> * Using device_create_with_groups() the device core will take complete care of
>    the attribute lifecycle, also allowing to remove fbcon_init_device()

Thanks for your advice, I will fix and refactor this code in the next patch.

Thanks and Regards,
Shixiong Ou.

>
> Thomas