linux-kernel - [PATCH v8 06/14] PCI/ERR: Add pci_walk_bridge() to pcie_do

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Date:   Fri,  2 Oct 2020 11:47:27 -0700
From:   Sean V Kelley <seanvk.dev@...gontracks.org>
To:     bhelgaas@...gle.com, Jonathan.Cameron@...wei.com,
        rafael.j.wysocki@...el.com, ashok.raj@...el.com,
        tony.luck@...el.com, sathyanarayanan.kuppuswamy@...el.com,
        qiuxu.zhuo@...el.com
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Sean V Kelley <sean.v.kelley@...el.com>
Subject: [PATCH v8 06/14] PCI/ERR: Add pci_walk_bridge() to pcie_do_recovery()

From: Sean V Kelley <sean.v.kelley@...el.com>

Consolidate subordinate bus checks with pci_walk_bus()
into pci_walk_bridge() for walking below potentially
AER affected bridges.

Suggested-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Sean V Kelley <sean.v.kelley@...el.com>
---
 drivers/pci/pcie/err.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index e68ea5243ff2..9b2130725ab6 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -146,12 +146,28 @@ static int report_resume(struct pci_dev *dev, void *data)
 	return 0;
 }
 
+/**
+ * pci_walk_bridge - walk bridges potentially AER affected
+ * @bridge   bridge which may be a Port.
+ * @cb       callback to be called for each device found
+ * @userdata arbitrary pointer to be passed to callback.
+ *
+ * If the device provided is a bridge, walk the subordinate bus,
+ * including any bridged devices on buses under this bus.
+ * Call the provided callback on each device found.
+ */
+static void pci_walk_bridge(struct pci_dev *bridge, int (*cb)(struct pci_dev *, void *),
+			    void *userdata)
+{
+	if (bridge->subordinate)
+		pci_walk_bus(bridge->subordinate, cb, userdata);
+}
+
 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 			pci_channel_state_t state,
 			pci_ers_result_t (*reset_subordinate_devices)(struct pci_dev *pdev))
 {
 	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
-	struct pci_bus *bus;
 	struct pci_dev *bridge;
 	int type;
 
@@ -167,23 +183,22 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	else
 		bridge = pci_upstream_bridge(dev);
 
-	bus = bridge->subordinate;
 	pci_dbg(dev, "broadcast error_detected message\n");
 	if (state == pci_channel_io_frozen) {
-		pci_walk_bus(bus, report_frozen_detected, &status);
+		pci_walk_bridge(bridge, report_frozen_detected, &status);
 		status = reset_subordinate_device(bridge);
 		if (status != PCI_ERS_RESULT_RECOVERED) {
 			pci_warn(dev, "subordinate device reset failed\n");
 			goto failed;
 		}
 	} else {
-		pci_walk_bus(bus, report_normal_detected, &status);
+		pci_walk_bridge(bridge, report_normal_detected, &status);
 	}
 
 	if (status == PCI_ERS_RESULT_CAN_RECOVER) {
 		status = PCI_ERS_RESULT_RECOVERED;
 		pci_dbg(dev, "broadcast mmio_enabled message\n");
-		pci_walk_bus(bus, report_mmio_enabled, &status);
+		pci_walk_bridge(bridge, report_mmio_enabled, &status);
 	}
 
 	if (status == PCI_ERS_RESULT_NEED_RESET) {
@@ -194,14 +209,14 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 		 */
 		status = PCI_ERS_RESULT_RECOVERED;
 		pci_dbg(dev, "broadcast slot_reset message\n");
-		pci_walk_bus(bus, report_slot_reset, &status);
+		pci_walk_bridge(bridge, report_slot_reset, &status);
 	}
 
 	if (status != PCI_ERS_RESULT_RECOVERED)
 		goto failed;
 
 	pci_dbg(dev, "broadcast resume message\n");
-	pci_walk_bus(bus, report_resume, &status);
+	pci_walk_bridge(bridge, report_resume, &status);
 
 	if (pcie_aer_is_native(bridge))
 		pcie_clear_device_status(bridge);
-- 
2.28.0