From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7EB31A4F for ; Mon, 21 Nov 2022 09:34:41 +0000 (UTC) Received: from pps.filterd (m0279865.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2AL8OfjJ020302; Mon, 21 Nov 2022 09:34:31 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id; s=qcppdkim1; bh=1g+/NvOojCm5ORZk0Of68tqHGjtQ7DzUQncn3xYRqdI=; b=kui3l0jVo0X27upPv3QGtfk3aM7nM1ncP/EkZBzRepxGyu6el0UfYu2up4eLFfUvhNCO O/pBHUk5pFeafYx0VjPrDG6/FJUCurorLRz9ayz2/OT3tnXzy9f5DjgaiYbY1r0krCyc Qu5qaNL92AV6M1UJiecL8yuA+xkDb6lg8h6Blet8ZTf1CIAK7ZCoENDPmTUTorwAXet3 3fc0lTqa764pzUq6KrtCWmyrBlRlS6KY4Fo7ScUytxHM4rkUObgMBVI54NdngMlHpwWt 8GSb8wgD7L39wuZQX7KiwiHiJV9BYqL2um74eVSbPxewQqUnJSCUMhdB2hS1JCx9W+Fj 8Q== 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 3kxrfbv0se-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 21 Nov 2022 09:34:31 +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 2AL9YSIW014860; Mon, 21 Nov 2022 09:34:28 GMT Received: from pps.reinject (localhost [127.0.0.1]) by APTAIPPMTA01.qualcomm.com (PPS) with ESMTP id 3kxr7nebf7-1; Mon, 21 Nov 2022 09:34:28 +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 2AL9YSFo014854; Mon, 21 Nov 2022 09:34:28 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 2AL9YRrW014851; Mon, 21 Nov 2022 09:34:28 +0000 Received: by cbsp-sh-gv.qualcomm.com (Postfix, from userid 4098150) id 531B23A3D; Mon, 21 Nov 2022 17:34:26 +0800 (CST) From: Qiang Yu To: mani@kernel.org, loic.poulain@linaro.org Cc: mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, mrana@quicinc.com, Qiang Yu Subject: [PATCH v4] bus: mhi: host: Disable preemption while processing data events Date: Mon, 21 Nov 2022 17:34:24 +0800 Message-Id: <1669023264-84125-1-git-send-email-quic_qianyu@quicinc.com> X-Mailer: git-send-email 2.7.4 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-GUID: ROqEnf6bKpIWBVofBuHScnuHzup_6-VB X-Proofpoint-ORIG-GUID: ROqEnf6bKpIWBVofBuHScnuHzup_6-VB X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-11-21_06,2022-11-18_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=762 malwarescore=0 suspectscore=0 phishscore=0 priorityscore=1501 clxscore=1011 impostorscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2211210075 Precedence: bulk X-Mailing-List: mhi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: If data processing of an event is scheduled out because core is busy handling multiple irqs, this can starve the processing of MHI M0 state change event on another core. Fix this issue by disabling irq on the core processing data events. Signed-off-by: Qiang Yu --- v3->v4: modify the comment v2->v3: modify the comment v1->v2: add comments about why we disable local irq drivers/bus/mhi/host/main.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index f3aef77a..6c804c3 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1029,11 +1029,17 @@ void mhi_ev_task(unsigned long data) { struct mhi_event *mhi_event = (struct mhi_event *)data; struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; + unsigned long flags; + /* + * When multiple IRQs arrive, the tasklet will be scheduled out with event ring lock + * acquired, causing other high priority events like M0 state transition getting stuck + * while trying to acquire the same event ring lock. Thus, let's disable local IRQs here. + */ + spin_lock_irqsave(&mhi_event->lock, flags); /* process all pending events */ - spin_lock_bh(&mhi_event->lock); mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX); - spin_unlock_bh(&mhi_event->lock); + spin_unlock_irqrestore(&mhi_event->lock, flags); } void mhi_ctrl_ev_task(unsigned long data) -- 2.7.4