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Message-ID: <24a001cb-5170-4a7d-b004-651e5da4d84e@kylinos.cn>
Date: Fri, 2 Feb 2024 16:56:25 +0800
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Subject: Re: [PATCH] drm/modes: Replace deprecated simple_strtol with kstrtol
Content-Language: en-US
To: Jani Nikula <jani.nikula@linux.intel.com>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
References: <20240201070226.3292315-1-liucong2@kylinos.cn>
 <87frych57g.fsf@intel.com>
From: Cong Liu <liucong2@kylinos.cn>
In-Reply-To: <87frych57g.fsf@intel.com>
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Dear Jani,

I want to apologize for the incorrect patch I submitted. You are right 
that the recommended replacements are not suitable drop-in replacements 
and I clearly did not test the changes thoroughly.
The kstrtol function requires null-terminated strings, so it is not 
appropriate for the conversion needed here. Given the issues, it is best 
to maintain the original implementation for now.

Best Regard.
liucong

On 2024/2/1 18:03, Jani Nikula wrote:
> On Thu, 01 Feb 2024, Cong Liu <liucong2@kylinos.cn> wrote:
>> This patch replaces the use of the deprecated simple_strtol [1] function
>> in the drm_modes.c file with the recommended kstrtol function. This change
>> improves error handling and boundary checks.
>>
>> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull
>>
>> Signed-off-by: Cong Liu <liucong2@kylinos.cn>
> 
> This is completely wrong, and obviously not tested at all.
> 
> The recommended replacements are *not* drop-in replacements. Look into
> the documentation of the functions.
> 
> BR,
> Jani.
> 
>> ---
>>   drivers/gpu/drm/drm_modes.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
>> index 893f52ee4926..fce0fb1df9b2 100644
>> --- a/drivers/gpu/drm/drm_modes.c
>> +++ b/drivers/gpu/drm/drm_modes.c
>> @@ -1942,7 +1942,7 @@ static int drm_mode_parse_cmdline_bpp(const char *str, char **end_ptr,
>>   		return -EINVAL;
>>   
>>   	str++;
>> -	bpp = simple_strtol(str, end_ptr, 10);
>> +	bpp = kstrtol(str, end_ptr, 10);
>>   	if (*end_ptr == str)
>>   		return -EINVAL;
>>   
>> @@ -1961,7 +1961,7 @@ static int drm_mode_parse_cmdline_refresh(const char *str, char **end_ptr,
>>   		return -EINVAL;
>>   
>>   	str++;
>> -	refresh = simple_strtol(str, end_ptr, 10);
>> +	refresh = kstrtol(str, end_ptr, 10);
>>   	if (*end_ptr == str)
>>   		return -EINVAL;
>>   
>> @@ -2033,7 +2033,7 @@ static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
>>   	int remaining, i;
>>   	char *end_ptr;
>>   
>> -	xres = simple_strtol(str, &end_ptr, 10);
>> +	xres = kstrtol(str, &end_ptr, 10);
>>   	if (end_ptr == str)
>>   		return -EINVAL;
>>   
>> @@ -2042,7 +2042,7 @@ static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
>>   	end_ptr++;
>>   
>>   	str = end_ptr;
>> -	yres = simple_strtol(str, &end_ptr, 10);
>> +	yres = kstrtol(str, &end_ptr, 10);
>>   	if (end_ptr == str)
>>   		return -EINVAL;
>>   
>> @@ -2100,7 +2100,7 @@ static int drm_mode_parse_cmdline_int(const char *delim, unsigned int *int_ret)
>>   		return -EINVAL;
>>   
>>   	value = delim + 1;
>> -	*int_ret = simple_strtol(value, &endp, 10);
>> +	*int_ret = kstrtol(value, &endp, 10);
>>   
>>   	/* Make sure we have parsed something */
>>   	if (endp == value)
>