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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jiri Pirko <jiri@resnulli.us>
Cc: David Miller <davem@davemloft.net>,
	vfalico@redhat.com, netdev@vger.kernel.org,
	stephen@networkplumber.org
Subject: Re: [PATCH net-next] bridge: remove a redundant synchronize_net()
Date: Thu, 04 Apr 2013 08:44:47 -0700	[thread overview]
Message-ID: <1365090287.3308.3.camel@edumazet-glaptop> (raw)
In-Reply-To: <20130404153530.GA1688@minipsycho.brq.redhat.com>

On Thu, 2013-04-04 at 17:35 +0200, Jiri Pirko wrote:

> It can be converted now to call_rcu. synchronize_rcu is making sure
> no packet is in flight when changing modes.

What changes exactly ? You don't really answer to my question with this
very vague sentence.

Because maybe the synchronize_net() in netdev_rx_handler_unregister()
is enough and you dont even need the call_rcu(). Thats was my question.

RCU barriers are not magical things we add when we are not exactly sure
of what is happening.

Like other barriers (wmb(), smb_wmb(), ...) we should document or
understand why they are needed.

  reply	other threads:[~2013-04-04 15:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-02 15:45 [PATCH net-next] bridge: remove a redundant synchronize_net() Eric Dumazet
2013-04-02 15:58 ` Veaceslav Falico
2013-04-02 16:12   ` David Miller
2013-04-02 16:27     ` Eric Dumazet
2013-04-02 18:19       ` David Miller
2013-04-04 15:35       ` Jiri Pirko
2013-04-04 15:44         ` Eric Dumazet [this message]
2013-04-04 16:03           ` Eric Dumazet
2013-04-04 16:08             ` Jiri Pirko
2013-04-04 16:07           ` Jiri Pirko
2013-04-04 16:18             ` Eric Dumazet

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