From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: txqueuelen has wrong units; should be time
Date: Mon, 28 Feb 2011 17:48:14 +0100
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Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>,
	Albert Cahalan <acahalan@gmail.com>,
	Mikael Abrahamsson <swmike@swm.pp.se>,
	linux-kernel <linux-kernel@vger.kernel.org>,
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To: "John W. Linville" <linville@tuxdriver.com>
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Le lundi 28 f=C3=A9vrier 2011 =C3=A0 11:11 -0500, John W. Linville a =C3=
=A9crit :
> On Sun, Feb 27, 2011 at 09:07:53PM +0100, Eric Dumazet wrote:
>=20
> > Qdisc should return to caller a good indication packet is queued or
> > dropped at enqueue() time... not later (aka : never)
> >=20
> > Accepting a packet at t0, and dropping it later at t0+limit without
> > giving any indication to caller is a problem.
>=20
> Can you elaborate on what problem this causes?  Is it any worse than
> if the packet is dropped at some later hop?
>=20
> Is there any API that could report the drop to the sender (at
> least a local one) without having to wait for the ack timeout?
> Should there be?
>=20

Not all protocols have ACKS ;)

dev_queue_xmit() returns an error code, some callers use it.