linux-kernel - [PATCH v2 3/4] PCI/ERR: Do not do recovery if DPC service is active

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Date:   Fri, 29 Dec 2017 12:54:18 +0530
From:   Oza Pawandeep <poza@...eaurora.org>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dongdong Liu <liudongdong3@...wei.com>,
        Gabriele Paoloni <gabriele.paoloni@...wei.com>,
        Keith Busch <keith.busch@...el.com>, Wei Zhang <wzhang@...com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Timur Tabi <timur@...eaurora.org>
Cc:     Oza Pawandeep <poza@...eaurora.org>
Subject: [PATCH v2 3/4] PCI/ERR: Do not do recovery if DPC service is active

If AER attempts to do recovery for any device, and DPC is active on
any upstream port, AER should not do recovery, since it will be handled
by DPC

Change-Id: Ida507ce9145f420e35302db34e967f1b421e15c9
Signed-off-by: Oza Pawandeep <poza@...eaurora.org>

diff --git a/drivers/pci/pcie/pcie-err.c b/drivers/pci/pcie/pcie-err.c
index 858c94c..1991cc8 100644
--- a/drivers/pci/pcie/pcie-err.c
+++ b/drivers/pci/pcie/pcie-err.c
@@ -274,6 +274,22 @@ pci_ers_result_t pci_broadcast_error_message(struct pci_dev *dev,
 	return result_data.result;
 }
 
+/*
+ * pcie_port_upstream_bridge - returns immediate upstream bridge.
+ * dev: pcie device
+ */
+static struct pci_dev *pcie_port_upstream_bridge(struct pci_dev *dev)
+{
+	struct pci_dev *parent;
+
+	parent = pci_upstream_bridge(dev);
+
+	if (parent && pci_is_pcie(parent))
+		return parent;
+
+	return NULL;
+}
+
 /**
  * pci_do_recovery - handle nonfatal/fatal error recovery process
  * @dev: pointer to a pci_dev data structure of agent detecting an error
@@ -287,9 +303,29 @@ void pci_do_recovery(struct pci_dev *dev, int severity)
 {
 	pci_ers_result_t status, result = PCI_ERS_RESULT_RECOVERED;
 	enum pci_channel_state state;
+	struct pcie_port_service_driver *driver;
+	struct pci_dev *pdev = dev;
 
 	mutex_lock(&pci_err_recovery_lock);
 
+	if (severity != PCI_ERR_DPC_FATAL) {
+		/*
+		 * DPC service could be running in RP
+		 * or any upstream switch.
+		 */
+		do {
+			driver = pci_find_dpc_service(pdev);
+			if (driver) {
+				dev_printk(KERN_NOTICE, &dev->dev,
+				"AER: Recovery to be done by DPC %s\n",
+				pci_name(dev));
+				mutex_unlock(&pci_err_recovery_lock);
+				return;
+			}
+		pdev = pcie_port_upstream_bridge(dev);
+		} while (pdev);
+	}
+
 	if ((severity == PCI_ERR_AER_FATAL) ||
 	    (severity == PCI_ERR_DPC_FATAL))
 		state = pci_channel_io_frozen;
-- 
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a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.