From patchwork Tue Mar 21 02:06:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 13182147 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 C9F52C76195 for ; Tue, 21 Mar 2023 02:06:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbjCUCGy (ORCPT ); Mon, 20 Mar 2023 22:06:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229572AbjCUCGs (ORCPT ); Mon, 20 Mar 2023 22:06:48 -0400 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C99BD305E8; Mon, 20 Mar 2023 19:06:45 -0700 (PDT) Received: from pps.filterd (m0333521.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32KM4pHX026340; Tue, 21 Mar 2023 02:06:42 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=H9r2il6PViKSpQVaulibxENpxkzMyrAhWfxHwqY8eGY=; b=es1YJ3vsQyoGuNvLze/XpPDfgf1/9n0YiY8ET6tPdm0G6Xe+tW1owSTHQykgY5664oIU 7B89dEivBZd0KEkx3vQb71ZoBCEMfGoMq05v6Ba0oq+8f+zobcMdCMorTNYMOGNvVD+O cGCw50BnEn0a8Vx1FowwibdiUGkWCL3C86bwj7dGTX+8eeSmx7t0O7r2w26K+m/qZJDC vWhPq3Q1EGeVBrTLbSr7f7XZ5mGndwybn6d510PPetcWQjpVD/7cw6p3kGc0Ug7xWwFh vSTJpfLwOF93bDI/h69Q59mbwWZL6jWCTUcjOxXfYDCRgSpzOSxhBBba+gFHBUdNcG8R 9Q== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3pd47tn0sr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Mar 2023 02:06:41 +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 32KNExeQ010388; Tue, 21 Mar 2023 02:06:40 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3peqjn4c5s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Mar 2023 02:06:40 +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 32L26T9e007440; Tue, 21 Mar 2023 02:06:39 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-8; Tue, 21 Mar 2023 02:06:39 +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 7/7] vhost-scsi: Reduce vhost_scsi_mutex use Date: Mon, 20 Mar 2023 21:06:24 -0500 Message-Id: <20230321020624.13323-8-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-GUID: QtG3BjkRHARJkLjfhDuFDNXl5a2DGMFy X-Proofpoint-ORIG-GUID: QtG3BjkRHARJkLjfhDuFDNXl5a2DGMFy Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org We on longer need to hold the vhost_scsi_mutex the entire time we set/clear the endpoint. The tv_tpg_mutex handles tpg accesses not related to the tpg list, the port link/unlink functions use the tv_tpg_mutex while accessing the tpg->vhost_scsi pointer, vhost_scsi_do_plug will no longer queue events after the virtqueue's backend has been cleared and flushed, and we don't drop our refcount to the tpg until after we have stopped cmds and wait for outstanding cmds to complete. This moves the vhost_scsi_mutex use to it's documented use of being used to access the tpg list. We then don't need to hold it while a flush is being performed causing other device's vhost_scsi_set_endpoint and vhost_scsi_make_tpg/vhost_scsi_drop_tpg calls to have to wait on a flakey device. Signed-off-by: Mike Christie --- drivers/vhost/scsi.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index d4372a4aff49..3b0b556c57ef 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -229,7 +229,10 @@ struct vhost_scsi_ctx { struct iov_iter out_iter; }; -/* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */ +/* + * Global mutex to protect vhost_scsi TPG list for vhost IOCTLs and LIO + * configfs management operations. + */ static DEFINE_MUTEX(vhost_scsi_mutex); static LIST_HEAD(vhost_scsi_list); @@ -1526,7 +1529,7 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds) * vhost_scsi_tpg with an active struct vhost_scsi_nexus * * The lock nesting rule is: - * vhost_scsi_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex + * vs->dev.mutex -> vhost_scsi_mutex -> tpg->tv_tpg_mutex -> vq->mutex */ static int vhost_scsi_set_endpoint(struct vhost_scsi *vs, @@ -1540,7 +1543,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, int index, ret, i, len; bool match = false; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ @@ -1561,6 +1563,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (vs->vs_tpg) memcpy(vs_tpg, vs->vs_tpg, len); + mutex_lock(&vhost_scsi_mutex); list_for_each_entry(tpg, &vhost_scsi_list, tv_tpg_list) { mutex_lock(&tpg->tv_tpg_mutex); if (!tpg->tpg_nexus) { @@ -1576,6 +1579,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) { if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) { mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); ret = -EEXIST; goto undepend; } @@ -1590,6 +1594,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (ret) { pr_warn("target_depend_item() failed: %d\n", ret); mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); goto undepend; } tpg->tv_tpg_vhost_count++; @@ -1599,6 +1604,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, } mutex_unlock(&tpg->tv_tpg_mutex); } + mutex_unlock(&vhost_scsi_mutex); if (match) { memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn, @@ -1654,7 +1660,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, kfree(vs_tpg); out: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; } @@ -1670,7 +1675,6 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, int index, ret, i; u8 target; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ for (index = 0; index < vs->dev.nvqs; ++index) { @@ -1757,12 +1761,10 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, vs->vs_tpg = NULL; WARN_ON(vs->vs_events_nr); mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return 0; err_dev: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; }