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=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 E75E7C433E2 for ; Tue, 1 Sep 2020 09:34:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6B02205CB for ; Tue, 1 Sep 2020 09:34:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="EE7fOFYS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726247AbgIAJeQ (ORCPT ); Tue, 1 Sep 2020 05:34:16 -0400 Received: from mail29.static.mailgun.info ([104.130.122.29]:52266 "EHLO mail29.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725848AbgIAJeP (ORCPT ); Tue, 1 Sep 2020 05:34:15 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1598952855; h=Date: Message-Id: Cc: To: References: In-Reply-To: From: Subject: Content-Transfer-Encoding: MIME-Version: Content-Type: Sender; bh=5ev5CbyXt+DzMyxbawpgmMJHFPkqjEdsYxGp0U0ejh4=; b=EE7fOFYSQ65Trf6M1BzLaKT0GsUDskXTmCPepbyODkxj3/aXfP97243eJv/uY8hol/EVCdQL pTJ6IPsqaPNEtcCAA4BwAVRvqXPQt76QhSED9JuBvkdUWcBqbG9FUSObsOCIko2kTJ83lmkh ln3SLr5ztEcfX+sarpV4IeGPtxM= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyI3YTAwOSIsICJsaW51eC13aXJlbGVzc0B2Z2VyLmtlcm5lbC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-west-2.postgun.com with SMTP id 5f4e158c4ba82a82fd8522bb (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 01 Sep 2020 09:34:04 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 47364C433CB; Tue, 1 Sep 2020 09:34:04 +0000 (UTC) Received: from potku.adurom.net (88-114-240-156.elisa-laajakaista.fi [88.114.240.156]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: kvalo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 12E10C433CA; Tue, 1 Sep 2020 09:34:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 12E10C433CA Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=kvalo@codeaurora.org Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: p54: avoid accessing the data mapped to streaming DMA From: Kalle Valo In-Reply-To: <20200802132949.26788-1-baijiaju@tsinghua.edu.cn> References: <20200802132949.26788-1-baijiaju@tsinghua.edu.cn> To: Jia-Ju Bai Cc: chunkeey@googlemail.com, davem@davemloft.net, kuba@kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.5.2 Message-Id: <20200901093404.47364C433CB@smtp.codeaurora.org> Date: Tue, 1 Sep 2020 09:34:04 +0000 (UTC) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Jia-Ju Bai wrote: > In p54p_tx(), skb->data is mapped to streaming DMA on line 337: > mapping = pci_map_single(..., skb->data, ...); > > Then skb->data is accessed on line 349: > desc->device_addr = ((struct p54_hdr *)skb->data)->req_id; > > This access may cause data inconsistency between CPU cache and hardware. > > To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in > a local variable before DMA mapping, and then the driver accesses this > local variable instead of skb->data. > > Cc: > Signed-off-by: Jia-Ju Bai > Acked-by: Christian Lamparter Patch applied to wireless-drivers-next.git, thanks. 478762855b5a p54: avoid accessing the data mapped to streaming DMA -- https://patchwork.kernel.org/patch/11696391/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches