Re: [PATCH RFC] ASoC: simple-card-utils: fix priv->dai_props indexing

[Laurentiu Mihalcea <laurentiumihalcea111@gmail.com>]

On 12/23/2024 2:48 AM, Kuninori Morimoto wrote:
> Hi Laurentiu
>
> Thank you for the patch
>
>> As of commit cb18cd26039f ("ASoC: soc-core: do rtd->id trick at
>> snd_soc_add_pcm_runtime()") the ID stored in the PCM runtime data can
>> no longer be safely used to index the priv->dai_props array. This is
>> because the ID may be modified during snd_soc_add_pcm_runtime(), thus
>> resulting in an ID that's no longer a valid array index.
>>
>> To fix this, use the position of the dai_link stored inside the PCM
>> runtime data relative to the start of the dai_link array as index into
>> the priv->dai_props array.
>>
>> Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
> (snip)
>> +#define runtime_simple_priv_to_props(priv, rtd)					\
>> +	((priv)->dai_props + ((rtd)->dai_link - (priv)->dai_link))
> Oh yes, indeed.
>
> But I wonder it is needed not only utils, but all drivers
> (= simple-card/audio-graph-card/audio-graph-card2).

At this point I'd say there's no need to do the replacement anywhere else. That's because the code
still using simple_priv_to_props() makes use of the link number to index the array, which is fine.
This is opposed to the PCM runtime data ID that may not correspond to a link number, thus making it
unfit for use as an array index.

>
> Why don't you just replace macro ?
>
> 	- #define simple_priv_to_props(priv, i) // old macro
> 	+ #define simple_priv_to_props(priv, i) // new macro
>
> Or, do you have any reasons ?
>
> In replase case, we would like to have the comment not only git-log but
> on header too.
>
>
> Thank you for your help !!
>
> Best regards
> ---
> Kuninori Morimoto

Thanks for taking your time to review this and sorry for the (very) late reply!