[RFC PATCH v1 3/6] PCI, ACPI: correctly update binding info when PCI hotplug event happens

[RFC PATCH v1 3/6] PCI, ACPI: correctly update binding info when PCI hotplug event happens

[Jiang Liu]

From: Jiang Liu <liuj97@gmail.com>

Currently acpi/pci_bind.c is used to maintain binding relationship
among ACPI and PCI devices. But it's broken when dealing PCI hotplug
events.

For the acpiphp driver, it's designed to update the binding relationship
when PCI hotplug event happensr, but the implementation is broken.
For PCI device hot-adding:
enable_device()
    pci_scan_slot()
    acpiphp_bus_add()
        acpi_bus_add()
	    acpi_pci_bind()
		acpi_get_pci_dev()
		    return NULL because dev->archdata.acpi_handle is
		    still unset
		return without updating actual binding relationship
    pci_bus_add_devices()
	pci_bus_add_device()
	    device_add()
		platform_notify()
		    acpi_bind_one()
			set dev->archdata.acpi_handle

For PCI device hot-removal,
disable_device()
    pci_stop_bus_device()
    __pci_remove_bus_device()
    acpiphp_bus_trim()
	acpi_bus_remove()
	    acpi_pci_unbind()
		return without really unbinding because PCI device has
		already been destroyed

For other PCI hotplug drivers, such as pciehp etc, they even don't
bother to update binding relationship. So hook into acpi_bind_one()
and acpi_unbind_one() in drivers/acpi/glue.c to update PCI/ACPI
binding relationship.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/acpi/glue.c     |    4 ++
 drivers/acpi/internal.h |    2 +
 drivers/acpi/pci_bind.c |  103 ++++++++++++++++++++++++++++++-----------------
 drivers/acpi/pci_root.c |   22 ----------
 4 files changed, 72 insertions(+), 59 deletions(-)

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 29a4a5c..1a07c3c 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -160,6 +160,8 @@ static int acpi_bind_one(struct device *dev, acpi_handle handle)
 	}
 	dev->archdata.acpi_handle = handle;
 
+	acpi_pci_bind_notify(dev->archdata.acpi_handle, dev, true);
+
 	status = acpi_bus_get_device(handle, &acpi_dev);
 	if (!ACPI_FAILURE(status)) {
 		int ret;
@@ -191,6 +193,8 @@ static int acpi_unbind_one(struct device *dev)
 			sysfs_remove_link(&acpi_dev->dev.kobj, "physical_node");
 		}
 
+		acpi_pci_bind_notify(dev->archdata.acpi_handle, dev, false);
+
 		acpi_detach_data(dev->archdata.acpi_handle,
 				 acpi_glue_data_handler);
 		dev->archdata.acpi_handle = NULL;
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ca75b9c..5396b20 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -93,4 +93,6 @@ static inline int suspend_nvs_save(void) { return 0; }
 static inline void suspend_nvs_restore(void) {}
 #endif
 
+void acpi_pci_bind_notify(acpi_handle handle, struct device *dev, bool bind);
+
 #endif /* _ACPI_INTERNAL_H_ */
diff --git a/drivers/acpi/pci_bind.c b/drivers/acpi/pci_bind.c
index 2ef0409..208e6cd 100644
--- a/drivers/acpi/pci_bind.c
+++ b/drivers/acpi/pci_bind.c
@@ -35,54 +35,56 @@
 #define _COMPONENT		ACPI_PCI_COMPONENT
 ACPI_MODULE_NAME("pci_bind");
 
-static int acpi_pci_unbind(struct acpi_device *device)
-{
-	struct pci_dev *dev;
+static int acpi_pci_bind(struct acpi_device *device);
 
-	dev = acpi_get_pci_dev(device->handle);
-	if (!dev)
-		goto out;
-
-	device_set_run_wake(&dev->dev, false);
+static int __acpi_pci_unbind(struct acpi_device *device, struct pci_dev *pdev)
+{
+	device_set_run_wake(&pdev->dev, false);
 	pci_acpi_remove_pm_notifier(device);
 
-	if (!dev->subordinate)
-		goto out;
+	if (pdev->subordinate) {
+		acpi_pci_irq_del_prt(pdev->subordinate);
+		device->ops.bind = NULL;
+		device->ops.unbind = NULL;
+	}
 
-	acpi_pci_irq_del_prt(dev->subordinate);
+	return 0;
+}
 
-	device->ops.bind = NULL;
-	device->ops.unbind = NULL;
+static int acpi_pci_unbind(struct acpi_device *device)
+{
+	int rc = 0;
+	struct pci_dev *pdev;
 
-out:
-	pci_dev_put(dev);
-	return 0;
+	pdev = acpi_get_pci_dev(device->handle);
+	if (pdev) {
+		rc = __acpi_pci_unbind(device, pdev);
+		pci_dev_put(pdev);
+	}
+
+	return rc;
 }
 
-static int acpi_pci_bind(struct acpi_device *device)
+static int __acpi_pci_bind(struct acpi_device *device, struct pci_dev *pdev)
 {
 	acpi_status status;
 	acpi_handle handle;
 	struct pci_bus *bus;
-	struct pci_dev *dev;
 
-	dev = acpi_get_pci_dev(device->handle);
-	if (!dev)
-		return 0;
-
-	pci_acpi_add_pm_notifier(device, dev);
+	pci_acpi_add_pm_notifier(device, pdev);
 	if (device->wakeup.flags.run_wake)
-		device_set_run_wake(&dev->dev, true);
+		device_set_run_wake(&pdev->dev, true);
 
 	/*
 	 * Install the 'bind' function to facilitate callbacks for
 	 * children of the P2P bridge.
 	 */
-	if (dev->subordinate) {
+	if (pdev->subordinate) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Device %04x:%02x:%02x.%d is a PCI bridge\n",
-				  pci_domain_nr(dev->bus), dev->bus->number,
-				  PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn)));
+				  pci_domain_nr(pdev->bus), pdev->bus->number,
+				  PCI_SLOT(pdev->devfn),
+				  PCI_FUNC(pdev->devfn)));
 		device->ops.bind = acpi_pci_bind;
 		device->ops.unbind = acpi_pci_unbind;
 	}
@@ -96,19 +98,29 @@ static int acpi_pci_bind(struct acpi_device *device)
 	 * TBD: Can _PRTs exist within the scope of non-bridge PCI devices?
 	 */
 	status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
-	if (ACPI_FAILURE(status))
-		goto out;
+	if (ACPI_SUCCESS(status)) {
+		if (pdev->subordinate)
+			bus = pdev->subordinate;
+		else
+			bus = pdev->bus;
+		acpi_pci_irq_add_prt(device->handle, bus);
+	}
+
+	return 0;
+}
 
-	if (dev->subordinate)
-		bus = dev->subordinate;
-	else
-		bus = dev->bus;
+static int acpi_pci_bind(struct acpi_device *device)
+{
+	int rc = 0;
+	struct pci_dev *pdev;
 
-	acpi_pci_irq_add_prt(device->handle, bus);
+	pdev = acpi_get_pci_dev(device->handle);
+	if (pdev) {
+		rc = __acpi_pci_bind(device, pdev);
+		pci_dev_put(pdev);
+	}
 
-out:
-	pci_dev_put(dev);
-	return 0;
+	return rc;
 }
 
 int acpi_pci_bind_root(struct acpi_device *device)
@@ -118,3 +130,20 @@ int acpi_pci_bind_root(struct acpi_device *device)
 
 	return 0;
 }
+
+void acpi_pci_bind_notify(acpi_handle handle, struct device *dev, bool bind)
+{
+	struct acpi_device *acpi_dev;
+
+	if (!dev_is_pci(dev))
+		return;
+	if (acpi_bus_get_device(handle, &acpi_dev))
+		return;
+	if (!acpi_dev || !acpi_dev->parent)
+		return;
+
+	if (bind && acpi_dev->parent->ops.bind)
+		__acpi_pci_bind(acpi_dev, to_pci_dev(dev));
+	else if (acpi_dev->parent->ops.unbind)
+		__acpi_pci_unbind(acpi_dev, to_pci_dev(dev));
+}
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7aff631..cd2f7af 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -195,21 +195,6 @@ static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
 	return AE_OK;
 }
 
-static void acpi_pci_bridge_scan(struct acpi_device *device)
-{
-	int status;
-	struct acpi_device *child = NULL;
-
-	if (device->flags.bus_address)
-		if (device->parent && device->parent->ops.bind) {
-			status = device->parent->ops.bind(device);
-			if (!status) {
-				list_for_each_entry(child, &device->children, node)
-					acpi_pci_bridge_scan(child);
-			}
-		}
-}
-
 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 
 static acpi_status acpi_pci_run_osc(acpi_handle handle,
@@ -456,7 +441,6 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	int result;
 	struct acpi_pci_root *root;
 	acpi_handle handle;
-	struct acpi_device *child;
 	u32 flags, base_flags;
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
@@ -557,12 +541,6 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	if (ACPI_SUCCESS(status))
 		result = acpi_pci_irq_add_prt(device->handle, root->bus);
 
-	/*
-	 * Scan and bind all _ADR-Based Devices
-	 */
-	list_for_each_entry(child, &device->children, node)
-		acpi_pci_bridge_scan(child);
-
 	/* Indicate support for various _OSC capabilities. */
 	if (pci_ext_cfg_avail(root->bus->self))
 		flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
-- 
1.7.1

[RFC PATCH v1 4/6] PCI, ACPI: update PCI slot information when PCI hotplug event happens

[Jiang Liu]

From: Jiang Liu <liuj97@gmail.com>

Currently the pci_slot driver doesn't update PCI slot information
when PCI device hotplug event happens, which may cause memory leak
and returning stale information to user.

So hook the BUS_NOTIFY_ADD_DEVICE/BUS_NOTIFY_DEL_DEVICE events to
update PCI slot information when PCI hotplug event happens.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/acpi/pci_slot.c |   84 +++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
index e50e31a..22cc00e 100644
--- a/drivers/acpi/pci_slot.c
+++ b/drivers/acpi/pci_slot.c
@@ -32,6 +32,7 @@
 #include <linux/acpi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
+#include <linux/pci-acpi.h>
 #include <linux/dmi.h>
 
 static bool debug;
@@ -123,12 +124,7 @@ struct callback_args {
 /*
  * register_slot
  *
- * Called once for each SxFy object in the namespace. Don't worry about
- * calling pci_create_slot multiple times for the same pci_bus:device,
- * since each subsequent call simply bumps the refcount on the pci_slot.
- *
- * The number of calls to pci_destroy_slot from unregister_slot is
- * symmetrical.
+ * Called once for each SxFy object in the namespace.
  */
 static acpi_status
 register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
@@ -145,6 +141,18 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
 	if (device < 0)
 		return AE_OK;
 
+	/* Avoid duplicated records for the same slot */
+	mutex_lock(&slot_list_lock);
+	list_for_each_entry(slot, &slot_list, list) {
+		pci_slot = slot->pci_slot;
+		if (pci_slot && pci_slot->bus == pci_bus &&
+		    pci_slot->number == device) {
+			mutex_unlock(&slot_list_lock);
+			return AE_OK;
+		}
+	}
+	mutex_unlock(&slot_list_lock);
+
 	slot = kmalloc(sizeof(*slot), GFP_KERNEL);
 	if (!slot) {
 		err("%s: cannot allocate memory\n", __func__);
@@ -354,17 +362,81 @@ static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
 	{}
 };
 
+static void acpi_pci_slot_notify_add(struct pci_dev *dev)
+{
+	acpi_handle handle;
+	struct callback_args context;
+
+	if (!dev->subordinate)
+		return;
+
+	handle = DEVICE_ACPI_HANDLE(&dev->dev);
+	context.root_handle = acpi_find_root_bridge_handle(dev);
+	if (handle && context.root_handle) {
+		context.pci_bus = dev->subordinate;
+		context.user_function = register_slot;
+		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
+				    register_slot, NULL, &context, NULL);
+	}
+}
+
+static void acpi_pci_slot_notify_del(struct pci_dev *dev)
+{
+	struct acpi_pci_slot *slot, *tmp;
+	struct pci_bus *bus = dev->subordinate;
+
+	if (!bus)
+		return;
+
+	mutex_lock(&slot_list_lock);
+	list_for_each_entry_safe(slot, tmp, &slot_list, list) {
+		if (slot->pci_slot && slot->pci_slot->bus == bus) {
+			list_del(&slot->list);
+			pci_destroy_slot(slot->pci_slot);
+			put_device(&bus->dev);
+			kfree(slot);
+		}
+	}
+	mutex_unlock(&slot_list_lock);
+}
+
+static int acpi_pci_slot_notify_fn(struct notifier_block *nb,
+				   unsigned long event, void *data)
+{
+	struct device *dev = data;
+
+	switch (event) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		acpi_pci_slot_notify_add(to_pci_dev(dev));
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+		acpi_pci_slot_notify_del(to_pci_dev(dev));
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_pci_slot_notifier = {
+	.notifier_call = &acpi_pci_slot_notify_fn,
+};
+
 static int __init
 acpi_pci_slot_init(void)
 {
 	dmi_check_system(acpi_pci_slot_dmi_table);
 	acpi_pci_register_driver(&acpi_pci_slot_driver);
+	bus_register_notifier(&pci_bus_type, &acpi_pci_slot_notifier);
+
 	return 0;
 }
 
 static void __exit
 acpi_pci_slot_exit(void)
 {
+	bus_unregister_notifier(&pci_bus_type, &acpi_pci_slot_notifier);
 	acpi_pci_unregister_driver(&acpi_pci_slot_driver);
 }
 
-- 
1.7.1

[RFC PATCH v1 5/6] PCI, ACPI: update ACPI hotplug slot information when PCI hotplug event happens

[Jiang Liu]

From: Jiang Liu <liuj97@gmail.com>

Currently the acpiphp driver fails to update hotplug slot information under
several conditions, such as:
1) The bridge device is removed through /sys/bus/pci/devices/.../remove
2) The bridge device is added/removed by PCI hotplug driver other than the
   acpiphp driver itself. For example, if an IO expansion box with ACPI
   hotplug slots available is hot-added by the pciehp driver, all ACPI
   hotplug slots won't be discovered by the acpiphp driver.

So hook the BUS_NOTIFY_ADD_DEVICE/BUS_NOTIFY_DEL_DEVICE events to
update ACPI hotplug slot information when PCI hotplug event happens.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/pci/hotplug/acpiphp_glue.c |   64 ++++++++++++++++++++++++++++++++++--
 1 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 73af337..44d055c 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -61,6 +61,7 @@ static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
 static void acpiphp_sanitize_bus(struct pci_bus *bus);
 static void acpiphp_set_hpp_values(struct pci_bus *bus);
 static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
+static struct acpiphp_bridge *acpiphp_handle_to_bridge(acpi_handle handle);
 
 /* callback routine to check for the existence of a pci dock device */
 static acpi_status
@@ -377,7 +378,7 @@ static inline void config_p2p_bridge_flags(struct acpiphp_bridge *bridge)
 
 
 /* allocate and initialize host bridge data structure */
-static void add_host_bridge(acpi_handle *handle)
+static void add_host_bridge(acpi_handle handle)
 {
 	struct acpiphp_bridge *bridge;
 	struct acpi_pci_root *root = acpi_pci_find_root(handle);
@@ -396,12 +397,14 @@ static void add_host_bridge(acpi_handle *handle)
 	init_bridge_misc(bridge);
 }
 
-
 /* allocate and initialize PCI-to-PCI bridge data structure */
-static void add_p2p_bridge(acpi_handle *handle)
+static void add_p2p_bridge(acpi_handle handle)
 {
 	struct acpiphp_bridge *bridge;
 
+	if (acpiphp_handle_to_bridge(handle))
+		return;
+
 	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
 	if (bridge == NULL) {
 		err("out of memory\n");
@@ -1419,6 +1422,58 @@ find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 	return AE_OK ;
 }
 
+static void acpiphp_hp_notify_add(struct pci_dev *dev)
+{
+	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
+
+	if (!dev->subordinate || !handle)
+		return;
+
+	/* check if this bridge has ejectable slots */
+	if (detect_ejectable_slots(handle) > 0) {
+		dbg("found PCI-to-PCI bridge at PCI %s\n", pci_name(dev));
+		add_p2p_bridge(handle);
+	}
+}
+
+static void acpiphp_hp_notify_del(struct pci_dev *dev)
+{
+	struct acpiphp_bridge *bridge, *tmp;
+	struct pci_bus *bus = dev->subordinate;
+
+	if (!bus)
+		return;
+
+	list_for_each_entry_safe(bridge, tmp, &bridge_list, list)
+		if (bridge->pci_bus == bus) {
+			cleanup_bridge(bridge);
+			break;
+		}
+}
+
+static int acpi_pci_hp_notify_fn(struct notifier_block *nb,
+				 unsigned long event, void *data)
+{
+	struct device *dev = data;
+
+	switch (event) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		acpiphp_hp_notify_add(to_pci_dev(dev));
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+		acpiphp_hp_notify_del(to_pci_dev(dev));
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_pci_hp_notifier = {
+	.notifier_call = &acpi_pci_hp_notify_fn,
+};
+
 static struct acpi_pci_driver acpi_pci_hp_driver = {
 	.add =		add_bridge,
 	.remove =	remove_bridge,
@@ -1439,6 +1494,8 @@ int __init acpiphp_glue_init(void)
 	else
 		acpi_pci_register_driver(&acpi_pci_hp_driver);
 
+	bus_register_notifier(&pci_bus_type, &acpi_pci_hp_notifier);
+
 	return 0;
 }
 
@@ -1450,6 +1507,7 @@ int __init acpiphp_glue_init(void)
  */
 void  acpiphp_glue_exit(void)
 {
+	bus_unregister_notifier(&pci_bus_type, &acpi_pci_hp_notifier);
 	acpi_pci_unregister_driver(&acpi_pci_hp_driver);
 }
 
-- 
1.7.1