From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 3wD54T0kSlzDqC2 for ; Thu, 27 Apr 2017 15:25:12 +1000 (AEST) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3R5OF0u146725 for ; Thu, 27 Apr 2017 01:25:04 -0400 Received: from e23smtp02.au.ibm.com (e23smtp02.au.ibm.com [202.81.31.144]) by mx0a-001b2d01.pphosted.com with ESMTP id 2a2xcmbcqy-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 27 Apr 2017 01:25:04 -0400 Received: from localhost by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 27 Apr 2017 15:25:00 +1000 Received: from d23av06.au.ibm.com (d23av06.au.ibm.com [9.190.235.151]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v3R5OomP66191386 for ; Thu, 27 Apr 2017 15:24:58 +1000 Received: from d23av06.au.ibm.com (localhost [127.0.0.1]) by d23av06.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v3R5OPgl027308 for ; Thu, 27 Apr 2017 15:24:26 +1000 From: Vaibhav Jain To: linuxppc-dev@lists.ozlabs.org Cc: Vaibhav Jain , Frederic Barrat , Andrew Donnellan , Ian Munsie , Christophe Lombard , Philippe Bergheaud , Greg Kurz , "Alastair D'Silva" , stable@vger.kernel.org Subject: [PATCH-RESEND v4] cxl: Force context lock during EEH flow Date: Thu, 27 Apr 2017 10:53:25 +0530 Message-Id: <20170427052325.11818-1-vaibhav@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 the we call the 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: Resend - Added Acks and Sign-offs. 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]; -- 2.9.3