From patchwork Fri Jul 16 20:52:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tyrel Datwyler X-Patchwork-Id: 12382851 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 8D969C636CE for ; Fri, 16 Jul 2021 20:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76C32613D8 for ; Fri, 16 Jul 2021 20:52:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234324AbhGPUz2 (ORCPT ); Fri, 16 Jul 2021 16:55:28 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:4906 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231462AbhGPUz2 (ORCPT ); Fri, 16 Jul 2021 16:55:28 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 16GKYI1D143184; Fri, 16 Jul 2021 16:52:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=b+jUyZpXkbPxHX+FcKkiHQHFGel43oMdtxDCCp0cFjU=; b=kLllTL+/hh0JP/3FKmbpmfu4SJYWv60jWjPuiP+yrqadvMegD48HFrrKsGcZDhs/5+/0 osqpODZHY73JFBKn9s3QYNiiTVuY8W0H2D58UlCgxX9i3HcTTjc24loHb+7Ym2xl7pik BpMIWNPTG4FUHX9Sl6upJZh4NwfQXtzPaNuftpxt1SVGzhbTlE4onHtlVK65xl5K2asg +gLsbjf+JEA2mJLlUsM1uL/E/PwPcAK8Cu8lpCXosjsq9hPCwK+dt6n6pc6gvIi2ySgR HtgXRJnpYWM+3yrXGz/e0wUGsrqWRilP3Doo1Nox7NZrRDBGVseyniFt0ia6AtSKOebu BQ== Received: from ppma03dal.us.ibm.com (b.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.11]) by mx0a-001b2d01.pphosted.com with ESMTP id 39ugn6he9v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 16 Jul 2021 16:52:25 -0400 Received: from pps.filterd (ppma03dal.us.ibm.com [127.0.0.1]) by ppma03dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 16GKmGXJ021484; Fri, 16 Jul 2021 20:52:25 GMT Received: from b03cxnp08026.gho.boulder.ibm.com (b03cxnp08026.gho.boulder.ibm.com [9.17.130.18]) by ppma03dal.us.ibm.com with ESMTP id 39rkgyaun5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 16 Jul 2021 20:52:24 +0000 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp08026.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 16GKqNEj13173176 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 16 Jul 2021 20:52:23 GMT Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 596E96A061; Fri, 16 Jul 2021 20:52:23 +0000 (GMT) Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BC7526A058; Fri, 16 Jul 2021 20:52:22 +0000 (GMT) Received: from vios4361.aus.stglabs.ibm.com (unknown [9.3.43.61]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 16 Jul 2021 20:52:22 +0000 (GMT) From: Tyrel Datwyler To: james.bottomley@hansenpartnership.com Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, brking@linux.ibm.com, Tyrel Datwyler , stable@vger.kernel.org Subject: [PATCH] ibmvfc: fix command state accounting and stale response detection Date: Fri, 16 Jul 2021 14:52:20 -0600 Message-Id: <20210716205220.1101150-1-tyreld@linux.ibm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: kgFMg1E-lAw2OAwCgTeTzaPXW6JJgyAP X-Proofpoint-ORIG-GUID: kgFMg1E-lAw2OAwCgTeTzaPXW6JJgyAP X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-16_09:2021-07-16,2021-07-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 lowpriorityscore=0 spamscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 adultscore=0 clxscore=1011 mlxscore=0 suspectscore=0 malwarescore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107160130 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Prior to commit 1f4a4a19508d ("scsi: ibmvfc: Complete commands outside the host/queue lock") responses to commands were completed sequentially with the host lock held such that a command had a basic binary state of active or free. It was therefore a simple affair of ensuring the assocaiated ibmvfc_event to a VIOS response was valid by testing that it was not already free. The lock relexation work to complete commands outside the lock inadverdently made it a trinary command state such that a command is either in flight, received and being completed, or completed and now free. This breaks the stale command detection logic as a command may be still marked active and been placed on the delayed completion list when a second stale response for the same command arrives. This can lead to double completions and list corruption. This issue was exposed by a recent VIOS regression were a missing memory barrier could occasionally result in the ibmvfc client receiveing a duplicate response for the same command. Fix the issue by introducing the atomic ibmvfc_event.active to track the trinary state of a command. The state is explicitly set to 1 when a command is successfully sent. The CRQ response handlers use atomic_dec_if_positive() to test for stale responses and correctly transition to the completion state when a active command is received. Finally, atomic_dec_and_test() is used to sanity check transistions when commands are freed as a result of a completion, or moved to the purge list as a result of error handling or adapter reset. Cc: stable@vger.kernel.org Fixes: 1f4a4a19508d ("scsi: ibmvfc: Complete commands outside the host/queue lock") Signed-off-by: Tyrel Datwyler --- drivers/scsi/ibmvscsi/ibmvfc.c | 19 +++++++++++++++++-- drivers/scsi/ibmvscsi/ibmvfc.h | 1 + 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index bee1bec49c09..935b01ee44b7 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.c +++ b/drivers/scsi/ibmvscsi/ibmvfc.c @@ -807,6 +807,13 @@ static int ibmvfc_init_event_pool(struct ibmvfc_host *vhost, for (i = 0; i < size; ++i) { struct ibmvfc_event *evt = &pool->events[i]; + /* + * evt->active states + * 1 = in flight + * 0 = being completed + * -1 = free/freed + */ + atomic_set(&evt->active, -1); atomic_set(&evt->free, 1); evt->crq.valid = 0x80; evt->crq.ioba = cpu_to_be64(pool->iu_token + (sizeof(*evt->xfer_iu) * i)); @@ -1017,6 +1024,7 @@ static void ibmvfc_free_event(struct ibmvfc_event *evt) BUG_ON(!ibmvfc_valid_event(pool, evt)); BUG_ON(atomic_inc_return(&evt->free) != 1); + BUG_ON(atomic_dec_and_test(&evt->active)); spin_lock_irqsave(&evt->queue->l_lock, flags); list_add_tail(&evt->queue_list, &evt->queue->free); @@ -1072,6 +1080,12 @@ static void ibmvfc_complete_purge(struct list_head *purge_list) **/ static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code) { + /* + * Anything we are failing should still be active. Otherwise, it + * implies we already got a response for the command and are doing + * something bad like double completing it. + */ + BUG_ON(!atomic_dec_and_test(&evt->active)); if (evt->cmnd) { evt->cmnd->result = (error_code << 16); evt->done = ibmvfc_scsi_eh_done; @@ -1723,6 +1737,7 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt, evt->done(evt); } else { + atomic_set(&evt->active, 1); spin_unlock_irqrestore(&evt->queue->l_lock, flags); ibmvfc_trc_start(evt); } @@ -3251,7 +3266,7 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost, return; } - if (unlikely(atomic_read(&evt->free))) { + if (unlikely(atomic_dec_if_positive(&evt->active))) { dev_err(vhost->dev, "Received duplicate correlation_token 0x%08llx!\n", crq->ioba); return; @@ -3778,7 +3793,7 @@ static void ibmvfc_handle_scrq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost return; } - if (unlikely(atomic_read(&evt->free))) { + if (unlikely(atomic_dec_if_positive(&evt->active))) { dev_err(vhost->dev, "Received duplicate correlation_token 0x%08llx!\n", crq->ioba); return; diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h index 4f0f3baefae4..92fb889d7eb0 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.h +++ b/drivers/scsi/ibmvscsi/ibmvfc.h @@ -745,6 +745,7 @@ struct ibmvfc_event { struct ibmvfc_target *tgt; struct scsi_cmnd *cmnd; atomic_t free; + atomic_t active; union ibmvfc_iu *xfer_iu; void (*done)(struct ibmvfc_event *evt); void (*_done)(struct ibmvfc_event *evt);