From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752466AbbKKTJX (ORCPT ); Wed, 11 Nov 2015 14:09:23 -0500 Received: from unicorn.mansr.com ([81.2.72.234]:45126 "EHLO unicorn.mansr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322AbbKKTJV convert rfc822-to-8bit (ORCPT ); Wed, 11 Nov 2015 14:09:21 -0500 From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= To: David Miller Cc: romieu@fr.zoreil.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, slash.tmp@free.fr Subject: Re: [PATCH v5] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller References: <20151111.112423.1751428739163066569.davem@davemloft.net> <20151111.140252.2214540370641368590.davem@davemloft.net> Date: Wed, 11 Nov 2015 19:09:19 +0000 In-Reply-To: <20151111.140252.2214540370641368590.davem@davemloft.net> (David Miller's message of "Wed, 11 Nov 2015 14:02:52 -0500 (EST)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Miller writes: > From: Måns Rullgård > Date: Wed, 11 Nov 2015 18:25:05 +0000 > >> If the TX DMA channel is idle when start_xmit is called, it can be >> started immediately. Checking the DMA status and starting it if >> idle has to be done atomically somehow. > > ->ndo_start_xmit() is guaranteed to be invoked atomically, protected > by the TX queue spinlock. Yes, but the DMA needs to be restarted from some other context if it was busy when start_xmit checked. -- Måns Rullgård mans@mansr.com