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=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 8B7D4C433E0 for ; Tue, 4 Aug 2020 02:17:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83BE420792 for ; Tue, 4 Aug 2020 02:17:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728476AbgHDCRr (ORCPT ); Mon, 3 Aug 2020 22:17:47 -0400 Received: from zg8tmtm5lju5ljm3lje2naaa.icoremail.net ([139.59.37.164]:48754 "HELO zg8tmtm5lju5ljm3lje2naaa.icoremail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1725975AbgHDCRq (ORCPT ); Mon, 3 Aug 2020 22:17:46 -0400 Received: from [166.111.139.118] (unknown [166.111.139.118]) by app-3 (Coremail) with SMTP id EQQGZQAH6sY2xShf9izvAw--.9502S2; Tue, 04 Aug 2020 10:17:28 +0800 (CST) Subject: Re: [PATCH] net: vmxnet3: avoid accessing the data mapped to streaming DMA To: David Miller Cc: doshir@vmware.com, pv-drivers@vmware.com, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200802131107.15857-1-baijiaju@tsinghua.edu.cn> <20200803.155949.39743839019093809.davem@davemloft.net> From: Jia-Ju Bai Message-ID: <6d4a6167-2480-0091-33a1-6b0cb81e4645@tsinghua.edu.cn> Date: Tue, 4 Aug 2020 10:17:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200803.155949.39743839019093809.davem@davemloft.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-CM-TRANSID: EQQGZQAH6sY2xShf9izvAw--.9502S2 X-Coremail-Antispam: 1UD129KBjvdXoW7Xw4xCr47tFWDKF18tF4ktFb_yoW3uFg_Cw 4Iywn3C398CwsruFn5tFy3Arn293yqqr1jvr1FqF1Ik343AFZFga1Uur97Jrn3tw4SyFZ3 uw1YqrWDXr1UWjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbIkYjsxI4VWxJwAYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I 6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM2 8CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0 cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I 8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI 64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8Jw Am72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0VAS07AlzVAYIcxG8wCY 02Avz4vE14v_Gr1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxV Aqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r12 6r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6x kF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWrJr0_WFyUJwCI42IY6I8E87Iv 67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf 9x07j5wIDUUUUU= X-CM-SenderInfo: xedlyxhdmxq3pvlqwxlxdovvfxof0/ Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/4 6:59, David Miller wrote: > From: Jia-Ju Bai > Date: Sun, 2 Aug 2020 21:11:07 +0800 > >> In vmxnet3_probe_device(), "adapter" is mapped to streaming DMA: >> adapter->adapter_pa = dma_map_single(..., adapter, ...); >> >> Then "adapter" is accessed at many places in this function. >> >> Theses accesses may cause data inconsistency between CPU cache and >> hardware. >> >> To fix this problem, dma_map_single() is called after these accesses. >> >> Signed-off-by: Jia-Ju Bai > 'adapter' is accessed everywhere, in the entire driver, not just here > in the probe function. Okay, replacing dma_map_single() with dma_alloc_coherent() may be better. If you think this solution is okay, I can submit a new patch. Best wishes, Jia-Ju Bai