Received-SPF: pass (google.com: domain of linux-wireless+bounces-3783-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Kalle Valo <kvalo@kernel.org>
To: Alexis =?utf-8?Q?Lothor=C3=A9?= <alexis.lothore@bootlin.com>
Cc: linux-wireless@vger.kernel.org,  Ajay Singh <ajay.kathat@microchip.com>,
  Claudiu Beznea <claudiu.beznea@tuxon.dev>,  Thomas Petazzoni
 <thomas.petazzoni@bootlin.com>,  linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] wifi: wilc1000: fix RCU usage
References: <20240215-wilc_fix_rcu_usage-v1-0-f610e46c6f82@bootlin.com>
Date: Mon, 19 Feb 2024 18:19:40 +0200
In-Reply-To: <20240215-wilc_fix_rcu_usage-v1-0-f610e46c6f82@bootlin.com>
	("Alexis =?utf-8?Q?Lothor=C3=A9=22's?= message of "Thu, 15 Feb 2024
 16:36:17 +0100")
Message-ID: <87h6i4mnoj.fsf@kernel.org>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux)
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Alexis Lothor=C3=A9 <alexis.lothore@bootlin.com> writes:

> This small series aims to fix multiple warnings observed when enabling
> CONFIG_PROVE_RCU_LIST:
> - add missing locks to create corresponding critical read sections
> - fix mix between RCU and SRCU API usage
>
> While at it, since SRCU API is already in use in the driver, any fix done
> on RCU usage was also done with the SRCU variant of RCU API. I do not
> really get why we are using SRCU in this driver instead of classic RCU, as
> it seems to be done in any other wireless driver.

And even more so, no other driver in drivers/net use SRCU.

> My understanding is that primary SRCU use case is for compatibility
> with realtime kernel, which needs to be preemptible everywhere. Has
> the driver been really developped with this constraint in mind ? If
> you have more details about this, feel free to educate me.

Alexis, if you have the time I recommend submitting a patchset
converting wilc1000 to use classic RCU. At least I have a hard time
understanding why SRCU is needed, especially after seeing the warning
you found.

--=20
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatc=
hes