From patchwork Tue Mar 21 02:06:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 666077 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 B2E0FC77B6C for ; Tue, 21 Mar 2023 02:06:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229854AbjCUCGr (ORCPT ); Mon, 20 Mar 2023 22:06:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229784AbjCUCGo (ORCPT ); Mon, 20 Mar 2023 22:06:44 -0400 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2DD162ED5B; Mon, 20 Mar 2023 19:06:41 -0700 (PDT) Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32KM4Nwp017041; Tue, 21 Mar 2023 02:06:37 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2022-7-12; bh=g/fWfgh2zgVn1G6uuOchSviM3Kl8lun20//Qo3MS6UI=; b=e5lDDR141feVlzQjLQ+orIVMQM5nAcXNQw+9NcsvrmWvAWN4ExsTvMnpfRlBIH7edEtY yuvB/QU68YScZkS3mBQP92V9F1pYVk/2dZKZ+TrFP4kDJwZ1nzeDu8x5LXZdtDqxf6r3 AoVhluaO15HVbWZPMy6SnKVwE7v3osmzxKIRl9AaV2g0ZRQS3f0yZnk/ERhPeIKVy60Z KdxE/VMnLz33O/TmvWt/SqcsKUxPstfDvwXSS9YiNdzhYuwuHzg5TnMTs3ISVyKfEXvE qSJKc0XpmU31dHQ1PfutFJrj71pn5KNTMG3XeqMObo6x9Vn1IhKUIvvqc33wM4maePpx jA== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3pd5bcd14f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Mar 2023 02:06:37 +0000 Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 32KNYkhf010738; Tue, 21 Mar 2023 02:06:37 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3peqjn4c4u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Mar 2023 02:06:36 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 32L26T9a007440; Tue, 21 Mar 2023 02:06:36 GMT Received: from mnchrist-mac.us.oracle.com (dhcp-10-154-165-250.vpn.oracle.com [10.154.165.250]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3peqjn4c0v-6; Tue, 21 Mar 2023 02:06:36 +0000 From: Mike Christie To: target-devel@vger.kernel.org, linux-scsi@vger.kernel.org, stefanha@redhat.com, jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com, virtualization@lists.linux-foundation.org Cc: Mike Christie Subject: [PATCH v2 5/7] vhost-scsi: Check for a cleared backend before queueing an event Date: Mon, 20 Mar 2023 21:06:22 -0500 Message-Id: <20230321020624.13323-6-michael.christie@oracle.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230321020624.13323-1-michael.christie@oracle.com> References: <20230321020624.13323-1-michael.christie@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-20_18,2023-03-20_02,2023-02-09_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxlogscore=999 phishscore=0 suspectscore=0 malwarescore=0 mlxscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303150002 definitions=main-2303210017 X-Proofpoint-ORIG-GUID: C9zns4ZwLWXe2SaW7yy-EhTv7Nry9sEO X-Proofpoint-GUID: C9zns4ZwLWXe2SaW7yy-EhTv7Nry9sEO Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org We currenly hold the vhost_scsi_mutex while clearing the endpoint and while performing vhost_scsi_do_plug, so tpg->vhost_scsi can't be freed from uder us, and to make sure anything queued is handled by the full call in vhost_scsi_clear_endpoint. This patch removes the need for the vhost_scsi_mutex for the latter case. In the next patches, we won't hold the vhost_scsi_mutex while flushing so this patch adds a check for the clearing of the virtqueue from vhost_scsi_clear_endpoint. We then know that once vhost_scsi_clear_endpoint has cleared the backend that no new events will be queued, and the flush after the vhost_vq_set_backend(vq, NULL) call will see everything that's been queued to that point. So the flush will then handle all events without the need for the vhost_scsi_mutex. Signed-off-by: Mike Christie --- drivers/vhost/scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index c945136ecf18..ba8097fcea43 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -2010,9 +2010,17 @@ vhost_scsi_do_plug(struct vhost_scsi_tpg *tpg, vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq; mutex_lock(&vq->mutex); + /* + * We can't queue events if the backend has been cleared, because + * we could end up queueing an event after the flush. + */ + if (!vhost_vq_get_backend(vq)) + goto unlock; + if (vhost_has_feature(vq, VIRTIO_SCSI_F_HOTPLUG)) vhost_scsi_send_evt(vs, tpg, lun, VIRTIO_SCSI_T_TRANSPORT_RESET, reason); +unlock: mutex_unlock(&vq->mutex); }