Date: Wed, 23 Jul 2008 13:14:41 -0700 (PDT)
Message-Id: <20080723.131441.200166513.davem@davemloft.net> (sfid-20080723_221445_778780_FB9E5226)
To: peterz@infradead.org
Cc: jarkao2@gmail.com, Larry.Finger@lwfinger.net, kaber@trash.net,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-wireless@vger.kernel.org, mingo@redhat.com
Subject: Re: Kernel WARNING: at net/core/dev.c:1330
 __netif_schedule+0x2c/0x98()
From: David Miller <davem@davemloft.net>
In-Reply-To: <1216810696.7257.175.camel@twins>
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	<20080723101352.GD4561@ff.dom.local>
	<1216810696.7257.175.camel@twins>
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From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 23 Jul 2008 12:58:16 +0200

> So I guess my question is, is netif_tx_lock() here to stay, or is the
> right fix to convert all those drivers to use __netif_tx_lock() which
> locks only a single queue?

It's staying.

It's trying to block all potential calls into the ->hard_start_xmit()
method of the driver, and the only reliable way to do that is to take
all the TX queue locks.  And in one form or another, we're going to
have this "grab/release all the TX queue locks" construct.

I find it interesting that this cannot be simply described to lockdep
:-)