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=ham 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 B3858C433F5 for ; Fri, 24 Sep 2021 07:04:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87B1B610CB for ; Fri, 24 Sep 2021 07:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244285AbhIXHFo (ORCPT ); Fri, 24 Sep 2021 03:05:44 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:20005 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244244AbhIXHFn (ORCPT ); Fri, 24 Sep 2021 03:05:43 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HG2wB5l1Czbmny; Fri, 24 Sep 2021 14:59:54 +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; Fri, 24 Sep 2021 15:04:07 +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; Fri, 24 Sep 2021 15:04:07 +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 CC: Jesper Dangaard Brouer , "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: <27bc803a-1687-a583-fa6b-3691fef7552e@huawei.com> Date: Fri, 24 Sep 2021 15:04:07 +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: netdev@vger.kernel.org On 2021/9/23 21:07, Ilias Apalodimas wrote: > On Thu, Sep 23, 2021 at 07:13:11PM +0800, Yunsheng Lin wrote: >> 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. > > Mind sending this one separately (and you can keep my reviewed-by). It > fits nicely on it's own and since I am not sure about the rest of the > changes yet, it would be nice to get this one in. I am not sure sending this one separately really makes sense, as it is mainly used to make supporting the "keep track of pp page when __skb_frag_ref() is called" in patch 5 easier. > > Cheers > /Ilias >> >>> >>> 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 >>>> >>> . >>> > . >