netdev - Re: [PATCH net-next v7 2/3] net: tcp: un-pin the tw

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Date: Wed, 5 Jun 2024 10:51:10 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Florian Westphal <fw@...len.de>
Cc: netdev@...r.kernel.org, Paolo Abeni <pabeni@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, vschneid@...hat.com,
	tglozar@...hat.com
Subject: Re: [PATCH net-next v7 2/3] net: tcp: un-pin the tw_timer

On 2024-06-04 16:08:48 [+0200], Florian Westphal wrote:
> After previous patch, even if timer fires immediately on another CPU,
> context that schedules the timer now holds the ehash spinlock, so timer
> cannot reap tw socket until ehash lock is released.

The two callers of inet_twsk_hashdance_schedule() have the comment:
| /* tw_timer is pinned, so we need to make sure BH are disabled
|  * in following section, otherwise timer handler could run before
|  * we complete the initialization.
|  */

This isn't accurate anymore. I would suggest to simply remove the
comment. The only reason for local_bh_disable() is (are) the lock(s).

> Signed-off-by: Florian Westphal <fw@...len.de>

Sebastian