netdev - Re: [PATCH net-next] once: add DO_ONCE

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Message-ID: <aV7JKsNpsmnf5oQL@agluck-desk3>
Date: Wed, 7 Jan 2026 12:59:22 -0800
From: "Luck, Tony" <tony.luck@...el.com>
To: Eric Dumazet <eric.dumazet@...il.com>
CC: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, netdev
	<netdev@...r.kernel.org>, Eric Dumazet <edumazet@...gle.com>, "Christophe
 Leroy" <christophe.leroy@...roup.eu>, Willy Tarreau <w@....eu>, "Reinette
 Chatre" <reinette.chatre@...el.com>
Subject: Re: [PATCH net-next] once: add DO_ONCE_SLOW() for sleepable contexts

On Sat, Oct 01, 2022 at 01:51:02PM -0700, Eric Dumazet wrote:
> +void __do_once_slow_done(bool *done, struct static_key_true *once_key,
> +			 struct module *mod)
> +	__releases(once_mutex)
> +{
> +	*done = true;
> +	mutex_unlock(&once_mutex);
> +	once_disable_jump(once_key, mod);

This seems to have been cut & pasted from __do_once_done(). But is there
a reason for the "sleepable" version to defer resetting the static key
in a work queue? Can't we just inline do:

	BUG_ON(!static_key_enabled(once_key));
	static_branch_disable(once_key);

> +}

-Tony

Credit to Reinette for raising this question. Blame me if I didn't spot
why a work queue is needed.