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=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6BEE0C433ED for ; Wed, 19 May 2021 17:03:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EA2861363 for ; Wed, 19 May 2021 17:03:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355500AbhESREv (ORCPT ); Wed, 19 May 2021 13:04:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:45748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355471AbhESREp (ORCPT ); Wed, 19 May 2021 13:04:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 673F76135C; Wed, 19 May 2021 17:03:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621443804; bh=jRb9LcGLC+A/55hxfV6NTeBK73W71OfoiFLQFFhNNb8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qJvjhfWAGz5zT9GwoJynSTwLOkNC+E4A7+rBQ0wM7XDe7zJxBca2KhMg9PabOIzDh 6UFXW/SZQN2ZCDmbQHuO/ua5KCF3SjkUBtexiSN0Pou2ObQjuRqTtiHGtgs2tLdIIe 2CIoCoZRnKfYI+astjwWUlxLn+kSeflpqTrGJeGg= Date: Wed, 19 May 2021 19:03:22 +0200 From: Greg KH To: Jianxiong Gao Cc: stable@vger.kernel.org, Christoph Hellwig , Marc Orr , sashal@kernel.org Subject: Re: [PATCH 5.4 v2 0/9] preserve DMA offsets when using swiotlb Message-ID: References: <20210518221818.2963918-1-jxgao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, May 19, 2021 at 09:42:42AM -0700, Jianxiong Gao wrote: > On Wed, May 19, 2021 at 1:11 AM Greg KH wrote: > > > > I still fail to understand why you can not just use the 5.10.y kernel or > > newer. What is preventing you from doing this if you wish to use this > > type of hardware? This is not a "regression" in that the 5.4.y kernel > > has never worked with this hardware before, it feels like a new feature. > > > NVMe + SWIOTLB is not a new feature. From my understanding it should > be supported by 5.4.y kernel correctly. Currently without the patch, any > NVMe device (along with some other devices that relies on offset to > work correctly), could be broken if the SWIOTLB is used on a 5.4.y kernel. Then do not do that, as obviously it never worked without your fixes, so this isn't a "regression". And again, why can you not just use 5.10.y? thanks, greg k-h