linux-kernel - Re: [PATCH] revocable: Remove redundant synchronize

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Message-ID: <CAMRc=MeZVbM1Bms41Roz-boi_jwJoMiEPniX=RuyZ2KHrxXmxg@mail.gmail.com>
Date: Wed, 21 Jan 2026 11:38:18 +0100
From: Bartosz Golaszewski <brgl@...nel.org>
To: Tzung-Bi Shih <tzungbi@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Danilo Krummrich <dakr@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] revocable: Remove redundant synchronize_srcu() call

On Wed, Jan 21, 2026 at 5:03 AM Tzung-Bi Shih <tzungbi@...nel.org> wrote:
>
> When allocating a revocable provider via revocable_provider_alloc(),
> there is no revocable consumers (i.e., RCU readers) yet.  Remove the
> redundant synchronize_srcu() call to save cycles.
>
> Signed-off-by: Tzung-Bi Shih <tzungbi@...nel.org>
> ---
> To address the performance impact reported in
> https://lore.kernel.org/linux-gpio/CAMRc=McrFa42mNWmZtD1HKKKZ+USUKpQAAME50wbfxPM7L72gA@mail.gmail.com/.
>
>  drivers/base/revocable.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/drivers/base/revocable.c b/drivers/base/revocable.c
> index f6cece275aac..b068e18a847d 100644
> --- a/drivers/base/revocable.c
> +++ b/drivers/base/revocable.c
> @@ -99,7 +99,6 @@ struct revocable_provider *revocable_provider_alloc(void *res)
>
>         init_srcu_struct(&rp->srcu);
>         rcu_assign_pointer(rp->res, res);
> -       synchronize_srcu(&rp->srcu);
>         kref_init(&rp->kref);
>
>         return rp;
> --
> 2.52.0.457.g6b5491de43-goog
>

Do you have an up-to-date integration branch with all the series and
fixes you posted that I could use for testing with GPIO?

Bart