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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 AD993C4332F for ; Thu, 23 Sep 2021 11:13:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ED2D61107 for ; Thu, 23 Sep 2021 11:13:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240581AbhIWLPD (ORCPT ); Thu, 23 Sep 2021 07:15:03 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:16286 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240498AbhIWLPB (ORCPT ); Thu, 23 Sep 2021 07:15:01 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4HFXZL6JGPz8tJf; Thu, 23 Sep 2021 19:12:42 +0800 (CST) Received: from dggpemm500005.china.huawei.com (7.185.36.74) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Thu, 23 Sep 2021 19:13:12 +0800 Received: from [10.69.30.204] (10.69.30.204) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.8; Thu, 23 Sep 2021 19:13:12 +0800 Subject: Re: [PATCH net-next 1/7] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA To: Ilias Apalodimas , Jesper Dangaard Brouer CC: "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , Networking , open list , , Jesper Dangaard Brouer , "Jonathan Lemon" , Alexander Lobakin , "Willem de Bruijn" , Cong Wang , "Paolo Abeni" , Kevin Hao , Aleksandr Nogikh , Marco Elver , , "Eric Dumazet" , Alexander Duyck , David Ahern References: <20210922094131.15625-1-linyunsheng@huawei.com> <20210922094131.15625-2-linyunsheng@huawei.com> <0ffa15a1-742d-a05d-3ea6-04ff25be6a29@redhat.com> From: Yunsheng Lin Message-ID: Date: Thu, 23 Sep 2021 19:13:11 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.69.30.204] X-ClientProxiedBy: dggeme720-chm.china.huawei.com (10.1.199.116) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/9/23 18:02, Ilias Apalodimas wrote: > Hi Jesper, > > On Thu, 23 Sept 2021 at 12:33, Jesper Dangaard Brouer > wrote: >> >> >> On 22/09/2021 11.41, Yunsheng Lin wrote: >>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c >>> index 1a6978427d6c..a65bd7972e37 100644 >>> --- a/net/core/page_pool.c >>> +++ b/net/core/page_pool.c >>> @@ -49,6 +49,12 @@ static int page_pool_init(struct page_pool *pool, >>> * which is the XDP_TX use-case. >>> */ >>> if (pool->p.flags & PP_FLAG_DMA_MAP) { >>> + /* DMA-mapping is not supported on 32-bit systems with >>> + * 64-bit DMA mapping. >>> + */ >>> + if (sizeof(dma_addr_t) > sizeof(unsigned long)) >>> + return -EINVAL; >> >> As I said before, can we please use another error than EINVAL. >> We should give drivers a chance/ability to detect this error, and e.g. >> fallback to doing DMA mappings inside driver instead. >> >> I suggest using EOPNOTSUPP 95 (Operation not supported). Will change it to EOPNOTSUPP, thanks. > > I am fine with both. In any case though the aforementioned driver can > just remove PP_FLAG_DMA_MAP and do it's own mappings. > > Regards > /Ilias >> >> -Jesper >> > . >