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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4CA9C4167B for ; Tue, 7 Nov 2023 07:19:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233029AbjKGHTy (ORCPT ); Tue, 7 Nov 2023 02:19:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229536AbjKGHTw (ORCPT ); Tue, 7 Nov 2023 02:19:52 -0500 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65FC1FC; Mon, 6 Nov 2023 23:19:49 -0800 (PST) Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3A73pvB7013472; Tue, 7 Nov 2023 07:19:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=u1DxfSI0u6GU0XwgXgfaS4gkCqfJ0FwPigY3T4KxkZQ=; b=gMY92RfxZOCObfwGRe2/698AFqathWTcUSO0I2k+IvT4BzHCEWqBJCnYeYeLkmhGWydg k37zNjLameuXOOz1CIJPfUOvyDRbBYyVkhj+DhXllF97hHk6NwRfxhM0T93UpTc7q6xs Reqt8/Ysi7YopzCcDOY5aqrgRx1MGf2qQPC/ZLuEQ9xiLXvA+HkFIMd2y96ZC3YlDTzi hpuWQCRLWhn9b/DmmRiuW6NsFIvT2/IMVZjzSA473+xTLLlC4UUZnPIdUz27K3+hKvs9 AzAD006q2l/Uts0ENWxzNziFCE4623lcrbwAdmI8psJgT5jljkkq7+sRb7OlyMackhDG 5w== Received: from nasanppmta01.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3u6xduan34-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 07 Nov 2023 07:19:17 +0000 Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 3A77JGHA030829 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 7 Nov 2023 07:19:16 GMT Received: from [10.253.15.27] (10.80.80.8) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.39; Mon, 6 Nov 2023 23:19:14 -0800 Message-ID: <92cc9fd2-eb05-4c2d-ad85-b3f411dece3e@quicinc.com> Date: Tue, 7 Nov 2023 15:19:02 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] bus: mhi: host: Add spinlock to protect WP access when queueing TREs Content-Language: en-US To: Manivannan Sadhasivam CC: , , , , , , Bhaumik Bhatt References: <1694594861-12691-1-git-send-email-quic_qianyu@quicinc.com> <1694594861-12691-2-git-send-email-quic_qianyu@quicinc.com> <20231106044126.GA2474@thinkpad> From: Qiang Yu In-Reply-To: <20231106044126.GA2474@thinkpad> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: _sUUq1hV39g9h-zZPqlYgM445QL1JcwK X-Proofpoint-ORIG-GUID: _sUUq1hV39g9h-zZPqlYgM445QL1JcwK X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-06_15,2023-11-02_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 lowpriorityscore=0 suspectscore=0 mlxlogscore=635 priorityscore=1501 spamscore=0 impostorscore=0 mlxscore=0 malwarescore=0 clxscore=1015 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2310240000 definitions=main-2311070059 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/6/2023 12:41 PM, Manivannan Sadhasivam wrote: > On Wed, Sep 13, 2023 at 04:47:40PM +0800, Qiang Yu wrote: >> From: Bhaumik Bhatt >> >> Protect WP accesses such that multiple threads queueing buffers for >> incoming data do not race and access the same WP twice. Ensure read and >> write locks for the channel are not taken in succession by dropping the >> read lock from parse_xfer_event() such that a callback given to client >> can potentially queue buffers and acquire the write lock in that process. >> Any queueing of buffers should be done without channel read lock acquired >> as it can result in multiple locks and a soft lockup. >> > This change is doing two things: > > 1. Unlocking xfer_cb to prevent potential lockup > 2. Protecting mhi_gen_tre() against concurrent access > > So you should split this into two patches and also add Fixes tag if appropriate. > > - Mani Hi Mani, thanks for review. I split this into two patch and add Fixes tag. > >> Signed-off-by: Bhaumik Bhatt >> Signed-off-by: Qiang Yu >> --- >> drivers/bus/mhi/host/main.c | 11 ++++++++++- >> 1 file changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c >> index dcf627b..13c4b89 100644 >> --- a/drivers/bus/mhi/host/main.c >> +++ b/drivers/bus/mhi/host/main.c >> @@ -642,6 +642,7 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl, >> mhi_del_ring_element(mhi_cntrl, tre_ring); >> local_rp = tre_ring->rp; >> >> + read_unlock_bh(&mhi_chan->lock); >> /* notify client */ >> mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); >> >> @@ -667,6 +668,7 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl, >> kfree(buf_info->cb_buf); >> } >> } >> + read_lock_bh(&mhi_chan->lock); >> } >> break; >> } /* CC_EOT */ >> @@ -1204,6 +1206,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, >> int eot, eob, chain, bei; >> int ret; >> >> + /* Protect accesses for reading and incrementing WP */ >> + write_lock_bh(&mhi_chan->lock); >> + >> buf_ring = &mhi_chan->buf_ring; >> tre_ring = &mhi_chan->tre_ring; >> >> @@ -1221,8 +1226,10 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, >> >> if (!info->pre_mapped) { >> ret = mhi_cntrl->map_single(mhi_cntrl, buf_info); >> - if (ret) >> + if (ret) { >> + write_unlock_bh(&mhi_chan->lock); >> return ret; >> + } >> } >> >> eob = !!(flags & MHI_EOB); >> @@ -1239,6 +1246,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, >> mhi_add_ring_element(mhi_cntrl, tre_ring); >> mhi_add_ring_element(mhi_cntrl, buf_ring); >> >> + write_unlock_bh(&mhi_chan->lock); >> + >> return 0; >> } >> >> -- >> 2.7.4 >> >>