Re: [PATCH] ALSA: control: Verify put() result when in debug mode

[Cezary Rojewski <cezary.rojewski@intel.com>]

On 2026-02-02 1:20 AM, Kuninori Morimoto wrote:

>> +static int snd_ctl_write_verify(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *control)
>> +{
>> +	struct snd_ctl_elem_value original;
>> +	int ret, retcmp;
>> +
>> +	ret = kctl->get(kctl, &original);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = kctl->put(kctl, control);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	retcmp = memcmp(&original.value.bytes.data[0], &control->value.bytes.data[0],
>> +			sizeof(original.value.bytes.data[0]));
>> +	if (retcmp)
>> +		retcmp = 1;
>> +
>> +	if (retcmp == ret)
>> +		pr_info("kctl->put() returned the expected value of '%d'\n", ret);
>> +	else
>> +		pr_warn("expected kctl->put() to return '%d' but got '%d'\n", ret, retcmp);
>> +	return ret;
>> +}
> 
> I think this is easy to read ?
> 
> 	static int snd_kctl_put(...)
> 	{
> 		if (IS_ENABLED(CONFIG_SND_CTL_DEBUG)) {
> 			/* Code with verification */
> 		} else {
> 			/* Code without verification */
> 		}
> 		return ret;
> 	}
> 
> 	...
> 
> 	if (!result)
> -		result = kctl->put(...);
> +		result = snd_kctl_put(...);

Hello,

I see the idea - reduce the number of if-statements in the actual code. 
What I decided to do in v2 is the above with a little twist - enlist 
macros. Not a fun for declaring yet another function with a single 
if-statement. Also, opted for "snd_ctl_put_xxx" instead of 
"snd_kctl_put_xxx" to match naming pattern most widely used in 
sound/core/control.c file.

Kind regards,
Czarek