Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932721AbdIRQen (ORCPT ); Mon, 18 Sep 2017 12:34:43 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:43842 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755934AbdIRQem (ORCPT ); Mon, 18 Sep 2017 12:34:42 -0400 Date: Mon, 18 Sep 2017 09:34:36 -0700 (PDT) Message-Id: <20170918.093436.1069699729581966538.davem@davemloft.net> To: rcochran@linutronix.de Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, andre.guedes@intel.com, anna-maria@linutronix.de, henrik@austad.us, jesus.sanchez-palencia@intel.com, john.stultz@linaro.org, tglx@linutronix.de, vinicius.gomes@intel.com Subject: Re: [PATCH RFC V1 net-next 0/6] Time based packet transmission From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.7 on Emacs 25.2 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 18 Sep 2017 09:34:39 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 649 Lines: 18 From: Richard Cochran Date: Mon, 18 Sep 2017 09:41:15 +0200 > - The driver does not handle out of order packets. If user space > sends a packet with an earlier Tx time, then the code should stop > the queue, reshuffle the descriptors accordingly, and then > restart the queue. The user should simply be not allowed to do this. Once the packet is in the device queue, that's it. You cannot insert a new packet to be transmitted before an already hw queued packet, period. Any out of order request should be rejected with an error. I'd say the same is true for requests to send packets timed in the past.