From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Stein Subject: Re: [PATCH RFC] can: add Virtual CAN Tunnel driver (vxcan) Date: Tue, 25 Apr 2017 10:14:17 +0200 Message-ID: <2991941.MzkBZeoEfP@ws-stein> References: <20170424201238.3587-1-socketcan@hartkopp.net> <1817567.PFpAbEA6ZR@ws-stein> <73a30dda-c0c6-a1f8-62d0-2cf4a193a7cc@hartkopp.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from webbox1416.server-home.net ([77.236.96.61]:43621 "EHLO webbox1416.server-home.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1428466AbdDYIOX (ORCPT ); Tue, 25 Apr 2017 04:14:23 -0400 In-Reply-To: <73a30dda-c0c6-a1f8-62d0-2cf4a193a7cc@hartkopp.net> Sender: linux-can-owner@vger.kernel.org List-ID: To: Oliver Hartkopp Cc: linux-can@vger.kernel.org Hi Oliver, On Tuesday 25 April 2017 08:28:11, Oliver Hartkopp wrote: > On 04/25/2017 07:35 AM, Alexander Stein wrote: > > On Monday 24 April 2017 22:12:37, Oliver Hartkopp wrote: > >> + > >> + netif_rx_ni(skb); > >> > > ^^^^^^^^^^ > > > > Wouldn't this result in the known out-of-order problem on SMP systems? > > I don't think so. > We're not dealing with irqs here that could reach different CPUs. > This is all in softirq/userspace context. > It's the same thing we have with the virtual CAN vcan. That would be great. I don't know the complete code path but is it possible that this xmit function is executed on different CPUs at the same time? e.g. multiple sockets/threads writing a CAN frame. Best regards, Alexander