From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB020C3A5A7 for ; Wed, 4 Sep 2019 13:22:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFFFD2168B for ; Wed, 4 Sep 2019 13:22:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="YuMj7bu6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730219AbfIDNWB (ORCPT ); Wed, 4 Sep 2019 09:22:01 -0400 Received: from pio-pvt-msa3.bahnhof.se ([79.136.2.42]:38082 "EHLO pio-pvt-msa3.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729020AbfIDNWB (ORCPT ); Wed, 4 Sep 2019 09:22:01 -0400 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTP id 3F5B03F7B6; Wed, 4 Sep 2019 15:21:59 +0200 (CEST) Authentication-Results: pio-pvt-msa3.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=YuMj7bu6; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa3.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa3.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JaEMwbwikqrj; Wed, 4 Sep 2019 15:21:58 +0200 (CEST) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTPA id AB2613F538; Wed, 4 Sep 2019 15:21:57 +0200 (CEST) Received: from localhost.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 1C21F360160; Wed, 4 Sep 2019 15:21:57 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1567603317; bh=yiIBmQhIS6s0ipKjugaVe6+eubjvGH0sI0nWCFLP7rc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=YuMj7bu680Kp7FvTxZJWVkWQxK0ymtONbkrPrLR7useEdrIv5vqWYL8/f3gnpGA8O 46LAMwg7ZwIjG28d0UWROFVJ8Ab+P9vXQk+AM5Ma7sjgqK3BHpeOvw+yMdnsnvigq/ bK0phgOaoY4JzjcjyPO+qmNiTYXoU7KuRF7LAChk= Subject: Re: dma api errors with swiotlb To: Christoph Hellwig Cc: "linux-kernel@vger.kernel.org" References: <20190904121722.GA15601@infradead.org> <4e21951d-025a-2b3d-14c8-878c6f237525@shipmail.org> <20190904125538.GA30177@infradead.org> <20190904131638.GA29164@infradead.org> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28VMware=29?= Organization: VMware Inc. Message-ID: Date: Wed, 4 Sep 2019 15:21:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190904131638.GA29164@infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/4/19 3:16 PM, Christoph Hellwig wrote: > On Wed, Sep 04, 2019 at 03:02:14PM +0200, Thomas Hellström (VMware) wrote: >> It looks like it does that, although when we send it, the SWIOTLB error has >> already occured and been printed out, and then the sequence starts again. > Well, the only way to really find out is to try. We also have a > backoff algorithm in the SCSI midlayer, so it should not be much of > an inpact. If you care about the warnings they can be disabled using > DMA_ATTR_NO_WARN. I have to admit that I'm not even sure the warnings > are all that useful, but that's something you need to take up with > the swiotlb maintainer. Yes, I guess so. I actually think the warnings make sense, since while the scsi midlayer handles this nicely, other drivers competing for the space might not. Thanks! Thomas