Re: [PATCH] ASoC: core: add snd_BUG_ON() check in devm_snd_soc_register_card()

[Bui Duc Phuc]

Hi Cezary,

Thank you for your review.

>
> Not sure whether we need such defenses. If we are to follow such
> approach, many ASoC-driver APIs require BUG_ON/WARN_ON() update.
>
> register_card() is typically called as a last step, once 'card' is
> already allocated. At the same time, the register_card() typically
> occurs in probe() context of given device so we're always certain the
> 'dev' is not NULL.
>
> TLDR: this is not a UAPI, (obvious) NULL-checks can be skipped.

I completely understand where you're coming from.
My thinking was that this function is referenced quite widely
(currently in 112 files).
Given how frequently it is used, I felt that adding a simple defensive
check here
could make the API a little more robust and help avoid potential
NULL pointer dereferences for both existing and future callers.

I wasn't suggesting that every ASoC API should be updated this way.
I was only thinking of APIs that are used very frequently, especially
those commonly called from probe paths.

Also, it's not always obvious to callers what assumptions a core API
relies on or
the context in which it is expected to be used.

That was simply the motivation behind this patch.

Best regards,
Phuc