Merge branch 'pci/hotplug'

- Remove unused cpcihp struct cpci_hp_controller_ops.hardware_test
  (Guilherme Giacomo Simoes)

- Remove unused cpqphp struct ctrl_dbg.ctrl (Christophe JAILLET)

- Clean up cpqphp PCIBIOS_* return value confusion (Ilpo Järvinen)

- Use pci_bus_read_dev_vendor_id() instead of hand-coded presence detection
  in cpqphp (Ilpo Järvinen)

- Simplify cpqphp enumeration, which is already simple-minded and doesn't
  handle devices below hot-added bridges (Ilpo Järvinen)

- Retain a reference to the pci_bus for the lifetime of a pci_slot to avoid
  a use-after-free when the thunderbolt driver resets USB4 host routers on
  boot, causing hotplug remove/add of downstream docks or other devices
  (Lukas Wunner)

* pci/hotplug:
  PCI: Fix use-after-free of slot->bus on hot remove
  PCI: cpqphp: Simplify PCI_ScanBusForNonBridge()
  PCI: cpqphp: Use define to read class/revision dword
  PCI: cpqphp: Use pci_bus_read_dev_vendor_id() to detect presence
  PCI: cpqphp: Fix PCIBIOS_* return value confusion
  PCI: cpqphp: Remove unused struct ctrl_dbg.ctrl
  PCI: cpcihp: Remove unused struct cpci_hp_controller_ops.hardware_test

Author: bjorn-helgaas

drivers/pci/hotplug/cpci_hotplug.h

@@ -44,7 +44,6 @@ struct cpci_hp_controller_ops {
 	int (*enable_irq)(void);
 	int (*disable_irq)(void);
 	int (*check_irq)(void *dev_id);
-	int (*hardware_test)(struct slot *slot, u32 value);
 	u8  (*get_power)(struct slot *slot);
 	int (*set_power)(struct slot *slot, int value);
 };

drivers/pci/hotplug/cpqphp_pci.c

@@ -12,8 +12,11 @@
  *
  */
 
+#define pr_fmt(fmt) "cpqphp: " fmt
+
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/printk.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
@@ -132,18 +135,6 @@ int cpqhp_unconfigure_device(struct pci_func *func)
 	return 0;
 }
 
-static int PCI_RefinedAccessConfig(struct pci_bus *bus, unsigned int devfn, u8 offset, u32 *value)
-{
-	u32 vendID = 0;
-
-	if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &vendID) == -1)
-		return -1;
-	if (PCI_POSSIBLE_ERROR(vendID))
-		return -1;
-	return pci_bus_read_config_dword(bus, devfn, offset, value);
-}
-
-
 /*
  * cpqhp_set_irq
  *
@@ -202,37 +193,37 @@ static int PCI_ScanBusForNonBridge(struct controller *ctrl, u8 bus_num, u8 *dev_
 {
 	u16 tdevice;
 	u32 work;
-	u8 tbus;
+	int ret = -1;
 
 	ctrl->pci_bus->number = bus_num;
 
 	for (tdevice = 0; tdevice < 0xFF; tdevice++) {
 		/* Scan for access first */
-		if (PCI_RefinedAccessConfig(ctrl->pci_bus, tdevice, 0x08, &work) == -1)
+		if (!pci_bus_read_dev_vendor_id(ctrl->pci_bus, tdevice, &work, 0))
+			continue;
+		ret = pci_bus_read_config_dword(ctrl->pci_bus, tdevice, PCI_CLASS_REVISION, &work);
+		if (ret)
 			continue;
 		dbg("Looking for nonbridge bus_num %d dev_num %d\n", bus_num, tdevice);
 		/* Yep we got one. Not a bridge ? */
 		if ((work >> 8) != PCI_TO_PCI_BRIDGE_CLASS) {
 			*dev_num = tdevice;
 			dbg("found it !\n");
 			return 0;
-		}
-	}
-	for (tdevice = 0; tdevice < 0xFF; tdevice++) {
-		/* Scan for access first */
-		if (PCI_RefinedAccessConfig(ctrl->pci_bus, tdevice, 0x08, &work) == -1)
-			continue;
-		dbg("Looking for bridge bus_num %d dev_num %d\n", bus_num, tdevice);
-		/* Yep we got one. bridge ? */
-		if ((work >> 8) == PCI_TO_PCI_BRIDGE_CLASS) {
-			pci_bus_read_config_byte(ctrl->pci_bus, PCI_DEVFN(tdevice, 0), PCI_SECONDARY_BUS, &tbus);
-			/* XXX: no recursion, wtf? */
-			dbg("Recurse on bus_num %d tdevice %d\n", tbus, tdevice);
-			return 0;
+		} else {
+			/*
+			 * XXX: Code whose debug printout indicated
+			 * recursion to buses underneath bridges might be
+			 * necessary was removed because it never did
+			 * any recursion.
+			 */
+			ret = 0;
+			pr_warn("missing feature: bridge scan recursion not implemented\n");
 		}
 	}
 
-	return -1;
+
+	return ret;
 }
 
 

drivers/pci/hotplug/cpqphp_sysfs.c

@@ -123,7 +123,6 @@ static int spew_debug_info(struct controller *ctrl, char *data, int size)
 struct ctrl_dbg {
 	int size;
 	char *data;
-	struct controller *ctrl;
 };
 
 #define MAX_OUTPUT	(4*PAGE_SIZE)

drivers/pci/slot.c

@@ -79,6 +79,7 @@ static void pci_slot_release(struct kobject *kobj)
 	up_read(&pci_bus_sem);
 
 	list_del(&slot->list);
+	pci_bus_put(slot->bus);
 
 	kfree(slot);
 }
@@ -261,14 +262,15 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 		goto err;
 	}
 
-	slot->bus = parent;
+	slot->bus = pci_bus_get(parent);
 	slot->number = slot_nr;
 
 	slot->kobj.kset = pci_slots_kset;
 
 	slot_name = make_slot_name(name);
 	if (!slot_name) {
 		err = -ENOMEM;
+		pci_bus_put(slot->bus);
 		kfree(slot);
 		goto err;
 	}