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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FADFC433F5 for ; Wed, 27 Oct 2021 07:44:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12F076109E for ; Wed, 27 Oct 2021 07:44:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240595AbhJ0HrA (ORCPT ); Wed, 27 Oct 2021 03:47:00 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:38124 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240575AbhJ0Hq7 (ORCPT ); Wed, 27 Oct 2021 03:46:59 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1635320674; h=Date: Message-ID: Cc: To: References: In-Reply-To: From: Subject: Content-Transfer-Encoding: MIME-Version: Content-Type: Sender; bh=mz8nJIGGpohR0wU+Oe8hK35Xu2THKa0asqPSQzly+Qw=; b=QA5nzslC1wYyuz2RKTxWwbkWsCoNSDY8FaEvsxDzB6GyEJAgeARb9s2lO9Tto/J05sBzp7lJ z9Fxc7UR8pYrJgv3bFBvP/bl201EGGUksIzQU9PG2swrm6hOlNnAHX6rr+CYO3h6w2FdaerR UutZ1Ken4l72jgJsWHvECkWyW6s= X-Mailgun-Sending-Ip: 69.72.43.7 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 6179035a321f2400517d1dfc (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 27 Oct 2021 07:44:26 GMT Sender: kvalo=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id D404FC43617; Wed, 27 Oct 2021 07:44:26 +0000 (UTC) Received: from tykki.adurom.net (tynnyri.adurom.net [51.15.11.48]) (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 71612C4338F; Wed, 27 Oct 2021 07:44:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 smtp.codeaurora.org 71612C4338F 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=fail smtp.mailfrom=codeaurora.org Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [PATCH] wcn36xx: add proper DMA memory barriers in rx path From: Kalle Valo In-Reply-To: <20211023001528.3077822-1-benl@squareup.com> References: <20211023001528.3077822-1-benl@squareup.com> To: Benjamin Li Cc: Bryan O'Donoghue , Loic Poulain , linux-arm-msm@vger.kernel.org, Benjamin Li , "David S. Miller" , Jakub Kicinski , "John W. Linville" , Eugene Krasnikov , wcn36xx@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.7.3 Message-ID: <163532066175.19793.9331674894554153079.kvalo@codeaurora.org> Date: Wed, 27 Oct 2021 07:44:26 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Benjamin Li wrote: > This is essentially exactly following the dma_wmb()/dma_rmb() usage > instructions in Documentation/memory-barriers.txt. > > The theoretical races here are: > > 1. DXE (the DMA Transfer Engine in the Wi-Fi subsystem) seeing the > dxe->ctrl & WCN36xx_DXE_CTRL_VLD write before the dxe->dst_addr_l > write, thus performing DMA into the wrong address. > > 2. CPU reading dxe->dst_addr_l before DXE unsets dxe->ctrl & > WCN36xx_DXE_CTRL_VLD. This should generally be harmless since DXE > doesn't write dxe->dst_addr_l (no risk of freeing the wrong skb). > > Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware") > Signed-off-by: Benjamin Li > Signed-off-by: Kalle Valo Patch applied to ath-next branch of ath.git, thanks. 9bfe38e064af wcn36xx: add proper DMA memory barriers in rx path -- https://patchwork.kernel.org/project/linux-wireless/patch/20211023001528.3077822-1-benl@squareup.com/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches