[PATCH 1/3] ppc/eeh: introduce EEH_PE_INVALID type PE

[PATCH 1/3] ppc/eeh: introduce EEH_PE_INVALID type PE

[Gavin Shan]

When EEH error happens on the PE whose PCI devices don't have
attached drivers. In function eeh_handle_event(), the default
value PCI_ERS_RESULT_NONE will be returned after iterating all
drivers of those PCI devices belonging to the PE. Actually, we
don't have installed drivers for the PCI devices. Under the
circumstance, we will remove the corresponding PCI bus of the PE,
including the associated EEH devices and PE instance. However,
we still need the information stored in the PE instance to do PE
reset after that. So it's unsafe to free the PE instance.

The patch introduces EEH_PE_INVALID type PE to address the issue.
When the PCI bus and the corresponding attached EEH devices are
removed, we will mark the PE as EEH_PE_INVALID. At later point,
the PE will be changed to EEH_PE_DEVICE or EEH_PE_BUS when the
corresponding EEH devices are attached again.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/eeh.h          |    7 ++--
 arch/powerpc/platforms/pseries/eeh_pe.c |   50 ++++++++++++++++++++++++-------
 2 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index 58c5ee6..afeb400 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -45,9 +45,10 @@ struct device_node;
  * in the corresponding PHB. Therefore, the root PEs should be created
  * against existing PHBs in on-to-one fashion.
  */
-#define EEH_PE_PHB	1	/* PHB PE    */
-#define EEH_PE_DEVICE 	2	/* Device PE */
-#define EEH_PE_BUS	3	/* Bus PE    */
+#define EEH_PE_INVALID	(1 << 0)	/* Invalid   */
+#define EEH_PE_PHB	(1 << 1)	/* PHB PE    */
+#define EEH_PE_DEVICE 	(1 << 2)	/* Device PE */
+#define EEH_PE_BUS	(1 << 3)	/* Bus PE    */
 
 #define EEH_PE_ISOLATED		(1 << 0)	/* Isolated PE		*/
 #define EEH_PE_RECOVERING	(1 << 1)	/* Recovering PE	*/
diff --git a/arch/powerpc/platforms/pseries/eeh_pe.c b/arch/powerpc/platforms/pseries/eeh_pe.c
index 047617e..8f95ffd 100644
--- a/arch/powerpc/platforms/pseries/eeh_pe.c
+++ b/arch/powerpc/platforms/pseries/eeh_pe.c
@@ -107,7 +107,7 @@ static struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
 		 * the PE for PHB has been determined when that
 		 * was created.
 		 */
-		if (pe->type == EEH_PE_PHB &&
+		if ((pe->type & EEH_PE_PHB) &&
 		    pe->phb == phb) {
 			eeh_unlock();
 			return pe;
@@ -219,7 +219,7 @@ static void *__eeh_pe_get(void *data, void *flag)
 	struct eeh_dev *edev = (struct eeh_dev *)flag;
 
 	/* Unexpected PHB PE */
-	if (pe->type == EEH_PE_PHB)
+	if (pe->type & EEH_PE_PHB)
 		return NULL;
 
 	/* We prefer PE address */
@@ -314,7 +314,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	 * components.
 	 */
 	pe = eeh_pe_get(edev);
-	if (pe) {
+	if (pe && !(pe->type & EEH_PE_INVALID)) {
 		if (!edev->pe_config_addr) {
 			pr_err("%s: PE with addr 0x%x already exists\n",
 				__func__, edev->config_addr);
@@ -331,6 +331,24 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 			edev->dn->full_name, pe->addr);
 
 		return 0;
+	} else if (pe && (pe->type & EEH_PE_INVALID)) {
+		list_add_tail(&edev->list, &pe->edevs);
+		edev->pe = pe;
+		/*
+		 * We're running to here because of PCI hotplug caused by
+		 * EEH recovery. We need clear EEH_PE_INVALID until the top.
+		 */
+		parent = pe;
+		while (parent) {
+			if (!(parent->type & EEH_PE_INVALID))
+				break;
+			parent->type &= ~EEH_PE_INVALID;
+			parent = parent->parent;
+		}
+		pr_debug("EEH: Add %s to Device PE#%x, Parent PE#%x\n",
+			edev->dn->full_name, pe->addr, pe->parent->addr);
+
+		return 0;
 	}
 
 	/* Create a new EEH PE */
@@ -385,7 +403,8 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
  */
 int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
 {
-	struct eeh_pe *pe, *parent;
+	struct eeh_pe *pe, *parent, *child;
+	int cnt;
 
 	if (!edev->pe) {
 		pr_warning("%s: No PE found for EEH device %s\n",
@@ -406,13 +425,22 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
 	 */
 	while (1) {
 		parent = pe->parent;
-		if (pe->type == EEH_PE_PHB)
+		if (pe->type & EEH_PE_PHB)
 			break;
 
-		if (list_empty(&pe->edevs) &&
-		    list_empty(&pe->child_list)) {
-			list_del(&pe->child);
-			kfree(pe);
+		if (list_empty(&pe->edevs)) {
+			cnt = 0;
+			list_for_each_entry(child, &pe->child_list, child) {
+				if (!(pe->type & EEH_PE_INVALID)) {
+					cnt++;
+					break;
+				}
+			}
+
+			if (!cnt)
+				pe->type |= EEH_PE_INVALID;
+			else
+				break;
 		}
 
 		pe = parent;
@@ -578,9 +606,9 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 	struct eeh_dev *edev;
 	struct pci_dev *pdev;
 
-	if (pe->type == EEH_PE_PHB) {
+	if (pe->type & EEH_PE_PHB) {
 		bus = pe->phb->bus;
-	} else if (pe->type == EEH_PE_BUS) {
+	} else if (pe->type & EEH_PE_BUS) {
 		edev = list_first_entry(&pe->edevs, struct eeh_dev, list);
 		pdev = eeh_dev_to_pci_dev(edev);
 		if (pdev)
-- 
1.7.5.4

[PATCH 2/3] ppc/eeh: remove EEH PE for normal PCI hotplug

[Gavin Shan]

Function eeh_rmv_from_parent_pe() could be called by the path of
either normal PCI hotplug, or EEH recovery. For the former case,
we need purge the corresponding PE on removal of the associated
PE bus.

The patch tries to cover that by passing more information to function
pcibios_remove_pci_devices() so that we know if the corresponding PE
needs to be purged or be marked as "invalid".

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/eeh.h              |    6 ++--
 arch/powerpc/include/asm/pci-bridge.h       |    1 +
 arch/powerpc/platforms/pseries/eeh.c        |   12 +++++----
 arch/powerpc/platforms/pseries/eeh_driver.c |    8 +++++-
 arch/powerpc/platforms/pseries/eeh_pe.c     |   35 +++++++++++++++++---------
 arch/powerpc/platforms/pseries/pci_dlpar.c  |   32 ++++++++++++++++++------
 6 files changed, 65 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index afeb400..b0ef738 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -185,7 +185,7 @@ static inline void eeh_unlock(void)
 typedef void *(*eeh_traverse_func)(void *data, void *flag);
 int __devinit eeh_phb_pe_create(struct pci_controller *phb);
 int eeh_add_to_parent_pe(struct eeh_dev *edev);
-int eeh_rmv_from_parent_pe(struct eeh_dev *edev);
+int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe);
 void *eeh_pe_dev_traverse(struct eeh_pe *root,
 		eeh_traverse_func fn, void *flag);
 void eeh_pe_restore_bars(struct eeh_pe *pe);
@@ -201,7 +201,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev);
 void __init eeh_addr_cache_build(void);
 void eeh_add_device_tree_early(struct device_node *);
 void eeh_add_device_tree_late(struct pci_bus *);
-void eeh_remove_bus_device(struct pci_dev *);
+void eeh_remove_bus_device(struct pci_dev *, int);
 
 /**
  * EEH_POSSIBLE_ERROR() -- test for possible MMIO failure.
@@ -240,7 +240,7 @@ static inline void eeh_add_device_tree_early(struct device_node *dn) { }
 
 static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
 
-static inline void eeh_remove_bus_device(struct pci_dev *dev) { }
+static inline void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe) { }
 
 static inline void eeh_lock(void) { }
 static inline void eeh_unlock(void) { }
diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 973df4d..a059cb9 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -192,6 +192,7 @@ static inline struct eeh_dev *of_node_to_eeh_dev(struct device_node *dn)
 extern struct pci_bus *pcibios_find_pci_bus(struct device_node *dn);
 
 /** Remove all of the PCI devices under this bus */
+extern void __pcibios_remove_pci_devices(struct pci_bus *bus, int purge_pe);
 extern void pcibios_remove_pci_devices(struct pci_bus *bus);
 
 /** Discover new pci devices under this bus, and add them */
diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c
index 18c168b..43f6ed4 100644
--- a/arch/powerpc/platforms/pseries/eeh.c
+++ b/arch/powerpc/platforms/pseries/eeh.c
@@ -817,6 +817,7 @@ EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
 /**
  * eeh_remove_device - Undo EEH setup for the indicated pci device
  * @dev: pci device to be removed
+ * @purge_pe: remove the PE or not
  *
  * This routine should be called when a device is removed from
  * a running system (e.g. by hotplug or dlpar).  It unregisters
@@ -824,7 +825,7 @@ EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
  * this device will no longer be detected after this call; thus,
  * i/o errors affecting this slot may leave this device unusable.
  */
-static void eeh_remove_device(struct pci_dev *dev)
+static void eeh_remove_device(struct pci_dev *dev, int purge_pe)
 {
 	struct eeh_dev *edev;
 
@@ -843,7 +844,7 @@ static void eeh_remove_device(struct pci_dev *dev)
 	dev->dev.archdata.edev = NULL;
 	pci_dev_put(dev);
 
-	eeh_rmv_from_parent_pe(edev);
+	eeh_rmv_from_parent_pe(edev, purge_pe);
 	eeh_addr_cache_rmv_dev(dev);
 	eeh_sysfs_remove_device(dev);
 }
@@ -851,21 +852,22 @@ static void eeh_remove_device(struct pci_dev *dev)
 /**
  * eeh_remove_bus_device - Undo EEH setup for the indicated PCI device
  * @dev: PCI device
+ * @purge_pe: remove the corresponding PE or not
  *
  * This routine must be called when a device is removed from the
  * running system through hotplug or dlpar. The corresponding
  * PCI address cache will be removed.
  */
-void eeh_remove_bus_device(struct pci_dev *dev)
+void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe)
 {
 	struct pci_bus *bus = dev->subordinate;
 	struct pci_dev *child, *tmp;
 
-	eeh_remove_device(dev);
+	eeh_remove_device(dev, purge_pe);
 
 	if (bus && dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
 		list_for_each_entry_safe(child, tmp, &bus->devices, bus_list)
-			 eeh_remove_bus_device(child);
+			 eeh_remove_bus_device(child, purge_pe);
 	}
 }
 EXPORT_SYMBOL_GPL(eeh_remove_bus_device);
diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c b/arch/powerpc/platforms/pseries/eeh_driver.c
index 8370ce7..37c2cf7 100644
--- a/arch/powerpc/platforms/pseries/eeh_driver.c
+++ b/arch/powerpc/platforms/pseries/eeh_driver.c
@@ -305,8 +305,14 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
 	/* pcibios will clear the counter; save the value */
 	cnt = pe->freeze_count;
 
+	/*
+	 * We don't remove the corresponding PE instances because
+	 * we need the information afterwords. The attached EEH
+	 * devices are expected to be attached soon when calling
+	 * into pcibios_add_pci_devices().
+	 */
 	if (bus)
-		pcibios_remove_pci_devices(bus);
+		__pcibios_remove_pci_devices(bus, 0);
 
 	/* Reset the pci controller. (Asserts RST#; resets config space).
 	 * Reconfigure bridges and devices. Don't try to bring the system
diff --git a/arch/powerpc/platforms/pseries/eeh_pe.c b/arch/powerpc/platforms/pseries/eeh_pe.c
index 8f95ffd..a2646cf 100644
--- a/arch/powerpc/platforms/pseries/eeh_pe.c
+++ b/arch/powerpc/platforms/pseries/eeh_pe.c
@@ -395,13 +395,14 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 /**
  * eeh_rmv_from_parent_pe - Remove one EEH device from the associated PE
  * @edev: EEH device
+ * @purge_pe: remove PE or not
  *
  * The PE hierarchy tree might be changed when doing PCI hotplug.
  * Also, the PCI devices or buses could be removed from the system
  * during EEH recovery. So we have to call the function remove the
  * corresponding PE accordingly if necessary.
  */
-int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
+int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe)
 {
 	struct eeh_pe *pe, *parent, *child;
 	int cnt;
@@ -428,19 +429,29 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
 		if (pe->type & EEH_PE_PHB)
 			break;
 
-		if (list_empty(&pe->edevs)) {
-			cnt = 0;
-			list_for_each_entry(child, &pe->child_list, child) {
-				if (!(pe->type & EEH_PE_INVALID)) {
-					cnt++;
-					break;
-				}
+		if (purge_pe) {
+			if (list_empty(&pe->edevs) &&
+			    list_empty(&pe->child_list)) {
+				list_del(&pe->child);
+				kfree(pe);
+			} else {
+				break;
 			}
+		} else {
+			if (list_empty(&pe->edevs)) {
+				cnt = 0;
+				list_for_each_entry(child, &pe->child_list, child) {
+					if (!(pe->type & EEH_PE_INVALID)) {
+						cnt++;
+						break;
+					}
+				}
 
-			if (!cnt)
-				pe->type |= EEH_PE_INVALID;
-			else
-				break;
+				if (!cnt)
+					pe->type |= EEH_PE_INVALID;
+				else
+					break;
+			}
 		}
 
 		pe = parent;
diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c b/arch/powerpc/platforms/pseries/pci_dlpar.c
index 3ccebc8..261a577 100644
--- a/arch/powerpc/platforms/pseries/pci_dlpar.c
+++ b/arch/powerpc/platforms/pseries/pci_dlpar.c
@@ -65,27 +65,43 @@ pcibios_find_pci_bus(struct device_node *dn)
 EXPORT_SYMBOL_GPL(pcibios_find_pci_bus);
 
 /**
- * pcibios_remove_pci_devices - remove all devices under this bus
+ * __pcibios_remove_pci_devices - remove all devices under this bus
+ * @bus: the indicated PCI bus
+ * @purge_pe: destroy the PE on removal of PCI devices
  *
  * Remove all of the PCI devices under this bus both from the
  * linux pci device tree, and from the powerpc EEH address cache.
+ * By default, the corresponding PE will be destroied during the
+ * normal PCI hotplug path. For PCI hotplug during EEH recovery,
+ * the corresponding PE won't be destroied and deallocated.
  */
-void pcibios_remove_pci_devices(struct pci_bus *bus)
+void __pcibios_remove_pci_devices(struct pci_bus *bus, int purge_pe)
 {
- 	struct pci_dev *dev, *tmp;
+	struct pci_dev *dev, *tmp;
 	struct pci_bus *child_bus;
 
 	/* First go down child busses */
 	list_for_each_entry(child_bus, &bus->children, node)
-		pcibios_remove_pci_devices(child_bus);
+		__pcibios_remove_pci_devices(child_bus, purge_pe);
 
 	pr_debug("PCI: Removing devices on bus %04x:%02x\n",
-		 pci_domain_nr(bus),  bus->number);
+		pci_domain_nr(bus),  bus->number);
 	list_for_each_entry_safe(dev, tmp, &bus->devices, bus_list) {
 		pr_debug("     * Removing %s...\n", pci_name(dev));
-		eeh_remove_bus_device(dev);
- 		pci_stop_and_remove_bus_device(dev);
- 	}
+		eeh_remove_bus_device(dev, purge_pe);
+		pci_stop_and_remove_bus_device(dev);
+	}
+}
+
+/**
+ * pcibios_remove_pci_devices - remove all devices under this bus
+ *
+ * Remove all of the PCI devices under this bus both from the
+ * linux pci device tree, and from the powerpc EEH address cache.
+ */
+void pcibios_remove_pci_devices(struct pci_bus *bus)
+{
+	__pcibios_remove_pci_devices(bus, 1);
 }
 EXPORT_SYMBOL_GPL(pcibios_remove_pci_devices);
 
-- 
1.7.5.4

[PATCH 3/3] ppc/eeh: global mutex to protect PE tree

[Gavin Shan]

We have missed lots of situations where the PE hierarchy tree need
protection through the EEH global mutex. The patch fixes that for
those public APIs implemented in eeh_pe.c. The only exception is
eeh_pe_restore_bars() because it calls eeh_pe_dev_traverse(), which
has been protected by the mutex.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/eeh_pe.c |   39 +++++++++++++++++++++++++-----
 1 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/eeh_pe.c b/arch/powerpc/platforms/pseries/eeh_pe.c
index a2646cf..07b6e4b 100644
--- a/arch/powerpc/platforms/pseries/eeh_pe.c
+++ b/arch/powerpc/platforms/pseries/eeh_pe.c
@@ -99,8 +99,6 @@ static struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
 {
 	struct eeh_pe *pe;
 
-	eeh_lock();
-
 	list_for_each_entry(pe, &eeh_phb_pe, child) {
 		/*
 		 * Actually, we needn't check the type since
@@ -114,8 +112,6 @@ static struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
 		}
 	}
 
-	eeh_unlock();
-
 	return NULL;
 }
 
@@ -192,14 +188,21 @@ void *eeh_pe_dev_traverse(struct eeh_pe *root,
 		return NULL;
 	}
 
+	eeh_lock();
+
 	/* Traverse root PE */
 	for (pe = root; pe; pe = eeh_pe_next(pe, root)) {
 		eeh_pe_for_each_dev(pe, edev) {
 			ret = fn(edev, flag);
-			if (ret) return ret;
+			if (ret) {
+				eeh_unlock();
+				return ret;
+			}
 		}
 	}
 
+	eeh_unlock();
+
 	return NULL;
 }
 
@@ -251,9 +254,7 @@ static struct eeh_pe *eeh_pe_get(struct eeh_dev *edev)
 	struct eeh_pe *root = eeh_phb_pe_get(edev->phb);
 	struct eeh_pe *pe;
 
-	eeh_lock();
 	pe = eeh_pe_traverse(root, __eeh_pe_get, edev);
-	eeh_unlock();
 
 	return pe;
 }
@@ -307,6 +308,8 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 {
 	struct eeh_pe *pe, *parent;
 
+	eeh_lock();
+
 	/*
 	 * Search the PE has been existing or not according
 	 * to the PE address. If that has been existing, the
@@ -316,6 +319,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	pe = eeh_pe_get(edev);
 	if (pe && !(pe->type & EEH_PE_INVALID)) {
 		if (!edev->pe_config_addr) {
+			eeh_unlock();
 			pr_err("%s: PE with addr 0x%x already exists\n",
 				__func__, edev->config_addr);
 			return -EEXIST;
@@ -327,6 +331,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 
 		/* Put the edev to PE */
 		list_add_tail(&edev->list, &pe->edevs);
+		eeh_unlock();
 		pr_debug("EEH: Add %s to Bus PE#%x\n",
 			edev->dn->full_name, pe->addr);
 
@@ -345,6 +350,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 			parent->type &= ~EEH_PE_INVALID;
 			parent = parent->parent;
 		}
+		eeh_unlock();
 		pr_debug("EEH: Add %s to Device PE#%x, Parent PE#%x\n",
 			edev->dn->full_name, pe->addr, pe->parent->addr);
 
@@ -354,6 +360,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	/* Create a new EEH PE */
 	pe = eeh_pe_alloc(edev->phb, EEH_PE_DEVICE);
 	if (!pe) {
+		eeh_unlock();
 		pr_err("%s: out of memory!\n", __func__);
 		return -ENOMEM;
 	}
@@ -370,6 +377,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	if (!parent) {
 		parent = eeh_phb_pe_get(edev->phb);
 		if (!parent) {
+			eeh_unlock();
 			pr_err("%s: No PHB PE is found (PHB Domain=%d)\n",
 				__func__, edev->phb->global_number);
 			edev->pe = NULL;
@@ -386,6 +394,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	list_add_tail(&pe->child, &parent->child_list);
 	list_add_tail(&edev->list, &pe->edevs);
 	edev->pe = pe;
+	eeh_unlock();
 	pr_debug("EEH: Add %s to Device PE#%x, Parent PE#%x\n",
 		edev->dn->full_name, pe->addr, pe->parent->addr);
 
@@ -413,6 +422,8 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe)
 		return -EEXIST;
 	}
 
+	eeh_lock();
+
 	/* Remove the EEH device */
 	pe = edev->pe;
 	edev->pe = NULL;
@@ -457,6 +468,8 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe)
 		pe = parent;
 	}
 
+	eeh_unlock();
+
 	return 0;
 }
 
@@ -502,7 +515,9 @@ static void *__eeh_pe_state_mark(void *data, void *flag)
  */
 void eeh_pe_state_mark(struct eeh_pe *pe, int state)
 {
+	eeh_lock();
 	eeh_pe_traverse(pe, __eeh_pe_state_mark, &state);
+	eeh_unlock();
 }
 
 /**
@@ -536,7 +551,9 @@ static void *__eeh_pe_state_clear(void *data, void *flag)
  */
 void eeh_pe_state_clear(struct eeh_pe *pe, int state)
 {
+	eeh_lock();
 	eeh_pe_traverse(pe, __eeh_pe_state_clear, &state);
+	eeh_unlock();
 }
 
 /**
@@ -598,6 +615,10 @@ static void *eeh_restore_one_device_bars(void *data, void *flag)
  */
 void eeh_pe_restore_bars(struct eeh_pe *pe)
 {
+	/*
+	 * We needn't take the EEH lock since eeh_pe_dev_traverse()
+	 * will take that.
+	 */
 	eeh_pe_dev_traverse(pe, eeh_restore_one_device_bars, NULL);
 }
 
@@ -617,6 +638,8 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 	struct eeh_dev *edev;
 	struct pci_dev *pdev;
 
+	eeh_lock();
+
 	if (pe->type & EEH_PE_PHB) {
 		bus = pe->phb->bus;
 	} else if (pe->type & EEH_PE_BUS) {
@@ -626,5 +649,7 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 			bus = pdev->bus;
 	}
 
+	eeh_unlock();
+
 	return bus;
 }
-- 
1.7.5.4