From patchwork Wed Apr 5 11:35:53 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vaibhav Jain X-Patchwork-Id: 747236 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3vykN66TtKz9s8B for ; Wed, 5 Apr 2017 21:37:26 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3vykN65YDTzDqKT for ; Wed, 5 Apr 2017 21:37:26 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 3vykLx2gYgzDqHW for ; Wed, 5 Apr 2017 21:36:25 +1000 (AEST) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v35BY3tD004407 for ; Wed, 5 Apr 2017 07:36:16 -0400 Received: from e28smtp05.in.ibm.com (e28smtp05.in.ibm.com [125.16.236.5]) by mx0a-001b2d01.pphosted.com with ESMTP id 29mytgg37m-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 05 Apr 2017 07:36:15 -0400 Received: from localhost by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 5 Apr 2017 17:06:09 +0530 Received: from d28av06.in.ibm.com (d28av06.in.ibm.com [9.184.220.48]) by d28relay04.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v35Ba9EH18940036 for ; Wed, 5 Apr 2017 17:06:09 +0530 Received: from d28av06.in.ibm.com (localhost [127.0.0.1]) by d28av06.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v35Ba7Ux010814 for ; Wed, 5 Apr 2017 17:06:08 +0530 Received: from vajain21.in.ibm.com ([9.109.223.88]) by d28av06.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id v35Ba7Hj010811; Wed, 5 Apr 2017 17:06:07 +0530 From: Vaibhav Jain To: Frederic Barrat , linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4] cxl: Force context lock during EEH flow Date: Wed, 5 Apr 2017 17:05:53 +0530 X-Mailer: git-send-email 2.9.3 X-TM-AS-MML: disable x-cbid: 17040511-0016-0000-0000-00000403B3C9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17040511-0017-0000-0000-000028ECC492 Message-Id: <20170405113553.7354-1-vaibhav@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-04-05_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704050101 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Philippe Bergheaud , Vaibhav Jain , stable@vger.kernel.org, Uma Krishnan , Ian Munsie , Andrew Donnellan , Christophe Lombard , Greg Kurz Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" During an eeh event when the cxl card is fenced and card sysfs attr perst_reloads_same_image is set following warning message is seen in the kernel logs: [ 60.622727] Adapter context unlocked with 0 active contexts [ 60.622762] ------------[ cut here ]------------ [ 60.622771] WARNING: CPU: 12 PID: 627 at ../drivers/misc/cxl/main.c:325 cxl_adapter_context_unlock+0x60/0x80 [cxl] Even though this warning is harmless, it clutters the kernel log during an eeh event. This warning is triggered as the EEH callback cxl_pci_error_detected doesn't obtain a context-lock before forcibly detaching all active context and when context-lock is released during call to cxl_configure_adapter from cxl_pci_slot_reset, a warning in cxl_adapter_context_unlock is triggered. To fix this warning, we acquire the adapter context-lock via cxl_adapter_context_lock() in the eeh callback cxl_pci_error_detected() once all the virtual AFU PHBs are notified and their contexts detached. The context-lock is released in cxl_pci_slot_reset() after the adapter is successfully reconfigured and before we call slot_reset callback on slice attached device-drivers. Cc: stable@vger.kernel.org Fixes: 70b565bbdb91("cxl: Prevent adapter reset if an active context exists") Reported-by: Andrew Donnellan Signed-off-by: Vaibhav Jain Acked-by: Frederic Barrat Reviewed-by: Matthew R. Ochs Tested-by: Uma Krishnan --- Change-Log: v3..v4 - Moved the call to context-unlock from cxl_pci_resume to cxl_pci_slot_reset to let cxlflash module activate its master context during slot reset. (Fred) v2..v3 - As discussed with Fred removed function cxl_adapter_context_force_lock() which may potentially expose the code to deadlock in the future. - Other details of changes in cxl_pci_error_detected() to fix an earlier issue of eeh callbacks not being passed on to all slices, is being reworked as a separate patch. v2..v1 - Moved the call to cxl_adapter_context_force_lock() from cxl_pci_error_detected() to cxl_remove. (Fred) --- drivers/misc/cxl/pci.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index b27ea98..dd9a128 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -1496,8 +1496,6 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev) if ((rc = cxl_native_register_psl_err_irq(adapter))) goto err; - /* Release the context lock as adapter is configured */ - cxl_adapter_context_unlock(adapter); return 0; err: @@ -1596,6 +1594,9 @@ static struct cxl *cxl_pci_init_adapter(struct pci_dev *dev) if ((rc = cxl_sysfs_adapter_add(adapter))) goto err_put1; + /* Release the context lock as adapter is configured */ + cxl_adapter_context_unlock(adapter); + return adapter; err_put1: @@ -1895,6 +1896,13 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev, cxl_ops->afu_deactivate_mode(afu, afu->current_mode); pci_deconfigure_afu(afu); } + + /* should take the context lock here */ + if (cxl_adapter_context_lock(adapter) != 0) + dev_warn(&adapter->dev, + "Couldn't take context lock with %d active-contexts\n", + atomic_read(&adapter->contexts_num)); + cxl_deconfigure_adapter(adapter); return result; @@ -1913,6 +1921,13 @@ static pci_ers_result_t cxl_pci_slot_reset(struct pci_dev *pdev) if (cxl_configure_adapter(adapter, pdev)) goto err; + /* + * Unlock context activation for the adapter. Ideally this should be + * done in cxl_pci_resume but cxlflash module tries to activate the + * master context as part of slot_reset callback. + */ + cxl_adapter_context_unlock(adapter); + for (i = 0; i < adapter->slices; i++) { afu = adapter->afu[i];