From patchwork Mon Sep 11 09:54:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qiang Yu X-Patchwork-Id: 13379878 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 59C0ACA0EC1 for ; Mon, 11 Sep 2023 21:19:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343699AbjIKVMU (ORCPT ); Mon, 11 Sep 2023 17:12:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236198AbjIKJzP (ORCPT ); Mon, 11 Sep 2023 05:55:15 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5345DE67; Mon, 11 Sep 2023 02:55:11 -0700 (PDT) Received: from pps.filterd (m0279863.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 38B59m6K027720; Mon, 11 Sep 2023 09:54:35 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=qcppdkim1; bh=r3cEFetEC69myoZ2rZNfopgEDH/i+rN96x2jjR/6AgA=; b=GCUl7IheVFl2ZdDjIDQuOO5M/Boc5GlhEPZ9jTF/cwj7dAN8LIRHMaq0u5L7RrW+8hGs 8UxAkn2MMCArUvaD/FpoZYaHAlnlffaw/DeiFfEj9Yv7GU/FqUdWQ9fj5a+wsf56ZspO gRGeLWleorNyIWEOR3dHP4GhnzG7EmKLWFr/tcshMCnxbYqpIUYVHYgSp1dLJKe5i9WR QE6yb4F5NFYVuTPzs+RecIljqP7v+vFo76gQIEuRR1aFUNZFuNkk0hhd4RgRoOA5fEEL NHR7y4rF7nezhb4rhedTqpEVvZruuJ9kj4IyqgnAZpR6pbF0g9rV7bS+SOeX7SZw0WYc nQ== Received: from aptaippmta01.qualcomm.com (tpe-colo-wan-fw-bordernet.qualcomm.com [103.229.16.4]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3t0gx9uewc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 11 Sep 2023 09:54:35 +0000 Received: from pps.filterd (APTAIPPMTA01.qualcomm.com [127.0.0.1]) by APTAIPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTP id 38B9sXnZ009626; Mon, 11 Sep 2023 09:54:33 GMT Received: from pps.reinject (localhost [127.0.0.1]) by APTAIPPMTA01.qualcomm.com (PPS) with ESMTP id 3t0hsk9q26-1; Mon, 11 Sep 2023 09:54:33 +0000 Received: from APTAIPPMTA01.qualcomm.com (APTAIPPMTA01.qualcomm.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 38B9sXDk009621; Mon, 11 Sep 2023 09:54:33 GMT Received: from cbsp-sh-gv.qualcomm.com (CBSP-SH-gv.ap.qualcomm.com [10.231.249.68]) by APTAIPPMTA01.qualcomm.com (PPS) with ESMTP id 38B9sX2R009620; Mon, 11 Sep 2023 09:54:33 +0000 Received: by cbsp-sh-gv.qualcomm.com (Postfix, from userid 4098150) id 48AB84879; Mon, 11 Sep 2023 17:54:32 +0800 (CST) From: Qiang Yu To: mani@kernel.org, quic_jhugo@quicinc.com Cc: mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, quic_mrana@quicinc.com, Bhaumik Bhatt , Qiang Yu Subject: [PATCH 1/2] bus: mhi: host: Add spinlock to protect WP access when queueing TREs Date: Mon, 11 Sep 2023 17:54:28 +0800 Message-Id: <1694426069-74140-2-git-send-email-quic_qianyu@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1694426069-74140-1-git-send-email-quic_qianyu@quicinc.com> References: <1694426069-74140-1-git-send-email-quic_qianyu@quicinc.com> X-QCInternal: smtphost X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: sIOFoJVdiUw_A2hDSO6A8JLua0ZAliDf X-Proofpoint-GUID: sIOFoJVdiUw_A2hDSO6A8JLua0ZAliDf X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-09-11_06,2023-09-05_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 bulkscore=0 mlxlogscore=781 malwarescore=0 suspectscore=0 adultscore=0 priorityscore=1501 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2309110091 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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. Signed-off-by: Bhaumik Bhatt Signed-off-by: Qiang Yu --- drivers/bus/mhi/host/main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index dcf627b..ce42205 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; @@ -1239,6 +1244,8 @@ 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; }