From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,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 EF8F8C43219 for ; Fri, 3 May 2019 00:53:43 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 758492070B for ; Fri, 3 May 2019 00:53:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 758492070B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44wDCT3tz2zDqNK for ; Fri, 3 May 2019 10:53:41 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=tyreld@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 44wD8X62dmzDqLC for ; Fri, 3 May 2019 10:51:07 +1000 (AEST) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x430lcZi135743; Thu, 2 May 2019 20:51:04 -0400 Received: from ppma01dal.us.ibm.com (83.d6.3fa9.ip4.static.sl-reverse.com [169.63.214.131]) by mx0a-001b2d01.pphosted.com with ESMTP id 2s8aj2hj8s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 May 2019 20:51:04 -0400 Received: from pps.filterd (ppma01dal.us.ibm.com [127.0.0.1]) by ppma01dal.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x42IsHxw013591; Thu, 2 May 2019 18:55:02 GMT Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by ppma01dal.us.ibm.com with ESMTP id 2s4eq3wvr4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 May 2019 18:55:01 +0000 Received: from b01ledav001.gho.pok.ibm.com (b01ledav001.gho.pok.ibm.com [9.57.199.106]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x430p2kF24183006 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 3 May 2019 00:51:02 GMT Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7071628058; Fri, 3 May 2019 00:51:02 +0000 (GMT) Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DDA6D2805A; Fri, 3 May 2019 00:51:01 +0000 (GMT) Received: from ltcalpine2-lp11.aus.stglabs.ibm.com (unknown [9.40.195.194]) by b01ledav001.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 3 May 2019 00:51:01 +0000 (GMT) From: Tyrel Datwyler To: james.bottomley@hansenpartnership.com Subject: [PATCH v2 3/3] ibmvscsi: fix tripping of blk_mq_run_hw_queue WARN_ON Date: Thu, 2 May 2019 19:50:58 -0500 Message-Id: <20190503005058.8768-3-tyreld@linux.ibm.com> X-Mailer: git-send-email 2.18.1 In-Reply-To: <20190503005058.8768-1-tyreld@linux.ibm.com> References: <20190503005058.8768-1-tyreld@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-02_13:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905030003 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tyrel Datwyler , martin.petersen@oracle.com, linux-scsi@vger.kernel.org, Tyrel Datwyler , brking@linux.ibm.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Tyrel Datwyler After a successful SRP login response we call scsi_unblock_requests() to kick any pending IO's. The callback to process this SRP response happens in a tasklet and therefore is in softirq context. The result of such is that when blk-mq is enabled it is no longer safe to call scsi_unblock_requests() from this context. The result of duing so triggers the following WARN_ON splat in dmesg after a host reset or CRQ reenablement. WARNING: CPU: 0 PID: 0 at block/blk-mq.c:1375 __blk_mq_run_hw_queue+0x120/0x180 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc8 #4 NIP [c0000000009771e0] __blk_mq_run_hw_queue+0x120/0x180 LR [c000000000977484] __blk_mq_delay_run_hw_queue+0x244/0x250 Call Trace: __blk_mq_delay_run_hw_queue+0x244/0x250 blk_mq_run_hw_queue+0x8c/0x1c0 blk_mq_run_hw_queues+0x60/0x90 scsi_run_queue+0x1e4/0x3b0 scsi_run_host_queues+0x48/0x80 login_rsp+0xb0/0x100 ibmvscsi_handle_crq+0x30c/0x3e0 ibmvscsi_task+0x54/0xe0 tasklet_action_common.isra.3+0xc4/0x1a0 __do_softirq+0x174/0x3f4 irq_exit+0xf0/0x120 __do_irq+0xb0/0x210 call_do_irq+0x14/0x24 do_IRQ+0x9c/0x130 hardware_interrupt_common+0x14c/0x150 This patch fixes the issue by introducing a new host action for unblocking the scsi requests in our seperate work thread. Signed-off-by: Tyrel Datwyler --- Changes in v2: no change drivers/scsi/ibmvscsi/ibmvscsi.c | 5 ++++- drivers/scsi/ibmvscsi/ibmvscsi.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 8df82c58e7b9..727c31dc11a0 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -1179,7 +1179,8 @@ static void login_rsp(struct srp_event_struct *evt_struct) be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta)); /* If we had any pending I/Os, kick them */ - scsi_unblock_requests(hostdata->host); + hostdata->action = IBMVSCSI_HOST_ACTION_UNBLOCK; + wake_up(&hostdata->work_wait_q); } /** @@ -2123,6 +2124,7 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata) spin_lock_irqsave(hostdata->host->host_lock, flags); switch (hostdata->action) { case IBMVSCSI_HOST_ACTION_NONE: + case IBMVSCSI_HOST_ACTION_UNBLOCK: break; case IBMVSCSI_HOST_ACTION_RESET: spin_unlock_irqrestore(hostdata->host->host_lock, flags); @@ -2164,6 +2166,7 @@ static int __ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata) return 0; case IBMVSCSI_HOST_ACTION_RESET: case IBMVSCSI_HOST_ACTION_REENABLE: + case IBMVSCSI_HOST_ACTION_UNBLOCK: default: break; } diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h index 04bcbc832dc9..d9bf502334ba 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.h +++ b/drivers/scsi/ibmvscsi/ibmvscsi.h @@ -92,6 +92,7 @@ enum ibmvscsi_host_action { IBMVSCSI_HOST_ACTION_NONE = 0, IBMVSCSI_HOST_ACTION_RESET, IBMVSCSI_HOST_ACTION_REENABLE, + IBMVSCSI_HOST_ACTION_UNBLOCK, }; /* all driver data associated with a host adapter */ -- 2.18.1