Re: [PATCH] gpio: don't use same lockdep class for all devm_gpiochip_add_data users

[Linus Walleij]

On Fri, Jul 31, 2020 at 2:39 PM Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote:

> Commit 959bc7b22bd2 ("gpio: Automatically add lockdep keys") documents
> in its commits message its intention to "create a unique class key for
> each driver".
>
> It does so by having gpiochip_add_data add in-place the definition of
> two static lockdep classes for LOCKDEP use. That way, every caller of
> the macro adds their gpiochip with unique lockdep classes.
>
> There are many indirect callers of gpiochip_add_data, however, via
> use of devm_gpiochip_add_data. devm_gpiochip_add_data has external
> linkage and all its users will share the same lockdep classes, which
> probably is not intended.
>
> Fix this by replicating the gpio_chip_add_data statics-in-macro for
> the devm_ version as well.
>
> Fixes: 959bc7b22bd2 ("gpio: Automatically add lockdep keys")
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> This doesn't fix any particular problem I ran into, but the code
> looked buggy, at least to my lockdep-user-not-developer eyes.

Thanks patch applied, I think we had this fixed before
but managed to loose it in some API rewrite. Thanks for
fixing it up!

Yours,
Linus Walleij