From: David Miller <davem@davemloft.net>
To: nhorman@tuxdriver.com
Cc: netdev@vger.kernel.org, amwang@redhat.com, eric.dumazet@gmail.com
Subject: Re: [PATCH v2 1/2] netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock
Date: Mon, 11 Feb 2013 19:19:45 -0500 (EST) [thread overview]
Message-ID: <20130211.191945.29632365432532819.davem@davemloft.net> (raw)
In-Reply-To: <1360614331-29247-2-git-send-email-nhorman@tuxdriver.com>
From: Neil Horman <nhorman@tuxdriver.com>
Date: Mon, 11 Feb 2013 15:25:30 -0500
> __netpoll_rcu_free is used to free netpoll structures when the rtnl_lock is
> already held. The mechanism is used to asynchronously call __netpoll_cleanup
> outside of the holding of the rtnl_lock, so as to avoid deadlock.
> Unfortunately, __netpoll_cleanup modifies pointers (dev->np), which means the
> rtnl_lock must be held while calling it. Further, it cannot be held, because
> rcu callbacks may be issued in softirq contexts, which cannot sleep.
>
> Fix this by converting the rcu callback to a work queue that is guaranteed to
> get scheduled in process context, so that we can hold the rtnl properly while
> calling __netpoll_cleanup
>
> Tested successfully by myself.
>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Applied.
next prev parent reply other threads:[~2013-02-12 0:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-07 14:56 [PATCH] netpoll: cleanup sparse warnings Neil Horman
2013-02-07 15:52 ` Eric Dumazet
2013-02-07 18:37 ` Neil Horman
2013-02-08 3:25 ` Eric Dumazet
2013-02-08 15:47 ` Neil Horman
2013-02-08 16:44 ` Eric Dumazet
2013-02-08 18:14 ` Neil Horman
2013-02-11 20:25 ` [PATCH v2 0/2] netpoll: Cleanup netpoll locking and " Neil Horman
2013-02-11 20:25 ` [PATCH v2 1/2] netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock Neil Horman
2013-02-12 0:19 ` David Miller [this message]
2013-02-11 20:25 ` [PATCH v2 2/2] netpoll: cleanup sparse warnings Neil Horman
2013-02-12 0:19 ` David Miller
2013-02-11 21:11 ` [PATCH v2 0/2] netpoll: Cleanup netpoll locking and " David Miller
2013-02-11 21:51 ` Neil Horman
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