From patchwork Wed Oct 7 20:54:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 268399 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A7A8C4363C for ; Wed, 7 Oct 2020 20:55:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDC2C20872 for ; Wed, 7 Oct 2020 20:55:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="p5bbpASx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728807AbgJGUzd (ORCPT ); Wed, 7 Oct 2020 16:55:33 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:43336 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728183AbgJGUz1 (ORCPT ); Wed, 7 Oct 2020 16:55:27 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 097KnSPj038239; Wed, 7 Oct 2020 20:55:23 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=aYEB9oNwgE3rL1pWC/WbwJ3rVzn4m1SbcZXmZ3XDWmI=; b=p5bbpASxPHqXtu3uPe6Sknw95w4NL949frRVtZpLaXFyqsleB19GpIjTKH1lhBXojjeB H/+3VDxSJYjPs8//bm5J3OZN79fyuXsl+ITbtJTkYDWhRONXBbvrG6CHsNkylWgDKtND SGXvwZAnOzwxSAexcWQQTrs3PEEsizylddvU8Jz1Xnq5urvgyRyKjwpAjhqvEY4/CNl7 jw3zOclVFHeCqsU+z+GGk3o6pKWQcslpJpvGNxkRWfr94Py9/MfhVUk7H5vwsfi2gjKy S7W1B9m5x55jjai4ksIKri7B1rH3RJuTmORUmm3q32thttlu9zRUbjuUaCL/kuZV/Eyj Cw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 33xhxn475m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 07 Oct 2020 20:55:23 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 097KpC1w028966; Wed, 7 Oct 2020 20:55:23 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 33yyjhpuh9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 07 Oct 2020 20:55:23 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 097KtLt9009077; Wed, 7 Oct 2020 20:55:21 GMT Received: from ol2.localdomain (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 07 Oct 2020 13:55:21 -0700 From: Mike Christie To: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, virtualization@lists.linux-foundation.org Subject: [PATCH 09/16] vhost scsi: fix cmd completion race Date: Wed, 7 Oct 2020 15:54:54 -0500 Message-Id: <1602104101-5592-10-git-send-email-michael.christie@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1602104101-5592-1-git-send-email-michael.christie@oracle.com> References: <1602104101-5592-1-git-send-email-michael.christie@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9767 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 adultscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 mlxscore=0 spamscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010070134 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9767 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 bulkscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=2 phishscore=0 mlxlogscore=999 adultscore=0 clxscore=1015 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010070134 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org We might not do the final se_cmd put from vhost_scsi_complete_cmd_work. When the last put happens a little later then we could race where vhost_scsi_complete_cmd_work does vhost_signal, the guest runs and sends more IO, and vhost_scsi_handle_vq runs but does not find any free cmds. This patch has us delay completing the cmd until the last lio core ref is dropped. We then know that once we signal to the guest that the cmd is completed that if it queues a new command it will find a free cmd. Signed-off-by: Mike Christie --- drivers/vhost/scsi.c | 42 +++++++++++++++--------------------------- 1 file changed, 15 insertions(+), 27 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index f6b9010..2fa48dd 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -322,7 +322,7 @@ static u32 vhost_scsi_tpg_get_inst_index(struct se_portal_group *se_tpg) return 1; } -static void vhost_scsi_release_cmd(struct se_cmd *se_cmd) +static void vhost_scsi_release_cmd_res(struct se_cmd *se_cmd) { struct vhost_scsi_cmd *tv_cmd = container_of(se_cmd, struct vhost_scsi_cmd, tvc_se_cmd); @@ -344,6 +344,16 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd) vhost_scsi_put_inflight(inflight); } +static void vhost_scsi_release_cmd(struct se_cmd *se_cmd) +{ + struct vhost_scsi_cmd *cmd = container_of(se_cmd, + struct vhost_scsi_cmd, tvc_se_cmd); + struct vhost_scsi *vs = cmd->tvc_vhost; + + llist_add(&cmd->tvc_completion_list, &vs->vs_completion_list); + vhost_work_queue(&vs->dev, &vs->vs_completion_work); +} + static u32 vhost_scsi_sess_get_index(struct se_session *se_sess) { return 0; @@ -366,28 +376,15 @@ static int vhost_scsi_get_cmd_state(struct se_cmd *se_cmd) return 0; } -static void vhost_scsi_complete_cmd(struct vhost_scsi_cmd *cmd) -{ - struct vhost_scsi *vs = cmd->tvc_vhost; - - llist_add(&cmd->tvc_completion_list, &vs->vs_completion_list); - - vhost_work_queue(&vs->dev, &vs->vs_completion_work); -} - static int vhost_scsi_queue_data_in(struct se_cmd *se_cmd) { - struct vhost_scsi_cmd *cmd = container_of(se_cmd, - struct vhost_scsi_cmd, tvc_se_cmd); - vhost_scsi_complete_cmd(cmd); + transport_generic_free_cmd(se_cmd, 0); return 0; } static int vhost_scsi_queue_status(struct se_cmd *se_cmd) { - struct vhost_scsi_cmd *cmd = container_of(se_cmd, - struct vhost_scsi_cmd, tvc_se_cmd); - vhost_scsi_complete_cmd(cmd); + transport_generic_free_cmd(se_cmd, 0); return 0; } @@ -433,15 +430,6 @@ static void vhost_scsi_free_evt(struct vhost_scsi *vs, struct vhost_scsi_evt *ev return evt; } -static void vhost_scsi_free_cmd(struct vhost_scsi_cmd *cmd) -{ - struct se_cmd *se_cmd = &cmd->tvc_se_cmd; - - /* TODO locking against target/backend threads? */ - transport_generic_free_cmd(se_cmd, 0); - -} - static int vhost_scsi_check_stop_free(struct se_cmd *se_cmd) { return target_put_sess_cmd(se_cmd); @@ -560,7 +548,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) } else pr_err("Faulted on virtio_scsi_cmd_resp\n"); - vhost_scsi_free_cmd(cmd); + vhost_scsi_release_cmd_res(se_cmd); } vq = -1; @@ -1096,7 +1084,7 @@ static u16 vhost_buf_to_lun(u8 *lun_buf) &prot_iter, exp_data_len, &data_iter))) { vq_err(vq, "Failed to map iov to sgl\n"); - vhost_scsi_release_cmd(&cmd->tvc_se_cmd); + vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd); goto err; } }