linux-kernel - Re: [PATCH v2 3/7] regulator/core: regulator_lock

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Message-ID: <CAE-0n53a75cgRNJOdn1=19OG_yJt9DDXHZ4quhZwCtZiQ1RUxQ@mail.gmail.com>
Date:   Wed, 30 Aug 2023 13:36:38 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Douglas Anderson <dianders@...omium.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/7] regulator/core: regulator_lock_nested: simplify
 nested locking

Quoting Michał Mirosław (2023-08-30 10:35:31)
> Simplify regulator locking by removing locking around locking.

Maybe this should say "Simplify regulator_lock_nested() by removing the
`regulator_nesting_mutex` now that rdev is locked whenever rdev->ref_cnt or
rdev->owner are modified"?

> rdev->ref check when unlocking is moved inside the critical section.

rdev->ref_cnt?

>
> This patch depends on commit 12235da8c80a ("kernel/locking: Add context
> to ww_mutex_trylock()").
>
> Note: return -EALREADY is removed as no caller depends on it and in that
> case the lock count is incremented anyway.

Where is -EALREADY removed in this patch? Perhaps "removed" should be
"ignored"?

Note: A return value of -EALREADY from ww_mutex_lock() in
regulator_lock_nested() is ignored as no caller depends on it.

>
> Reviewed-by: Douglas Anderson <dianders@...omium.org>
> Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>