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From: Kalle Valo <kvalo@kernel.org>
To: "Alexis Lothoré" <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
Date: Mon, 19 Feb 2024 18:34:46 +0200	[thread overview]
Message-ID: <87cyssmmzd.fsf@kernel.org> (raw)
In-Reply-To: <b3c31f4c-e837-47b6-bd0d-e8cf2b9964aa@bootlin.com> ("Alexis Lothoré"'s message of "Mon, 19 Feb 2024 17:24:55 +0100")

Alexis Lothoré <alexis.lothore@bootlin.com> writes:

> On 2/19/24 17:19, Kalle Valo wrote:
>
>> Alexis Lothoré <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.
>
> If nobody else comes in with a strong argument in favor of keeping
> SRCU

And emphasis on the word "strong"...

> yes I can certainly add that to my backlog :)

Thanks! Your wilc1000 backlog is getting long, I hope your todo software
won't overload ;)

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

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

      reply	other threads:[~2024-02-19 16:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-15 15:36 [PATCH 0/4] wifi: wilc1000: fix RCU usage Alexis Lothoré
2024-02-15 15:36 ` [PATCH 1/4] wifi: wilc1000: split deeply nested RCU list traversal in dedicated helper Alexis Lothoré
2024-02-19 16:21   ` Kalle Valo
2024-02-15 15:36 ` [PATCH 2/4] wifi: wilc1000: use SRCU instead of RCU for vif list traversal Alexis Lothoré
2024-02-15 15:36 ` [PATCH 3/4] wifi: wilc1000: fix declarations ordering Alexis Lothoré
2024-02-15 15:36 ` [PATCH 4/4] wifi: wilc1000: add missing read critical sections around vif list traversal Alexis Lothoré
2024-02-19 16:19 ` [PATCH 0/4] wifi: wilc1000: fix RCU usage Kalle Valo
2024-02-19 16:24   ` Alexis Lothoré
2024-02-19 16:34     ` Kalle Valo [this message]

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