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Commit 87831273 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
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ACPI / hotplug / PCI: Unified notify handler for hotplug events 



Using the hotplug context objects introduced previously rework the
ACPI-based PCI hotplug (ACPIPHP) core code so that all notifications
for ACPI device objects corresponding to the hotplug PCI devices are
handled by one function, handle_hotplug_event(), which recognizes
whether it has to handle a bridge or a function.

In addition to code size reduction it allows some ugly pieces of code
where notify handlers have to be uninstalled and installed again to
go away.  Moreover, it fixes a theoretically possible race between
handle_hotplug_event() and free_bridge() tearing down data structures
for the same handle.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent cb7b8ced

drivers/pci/hotplug/acpiphp.h

+1 −0
Original line number Diff line number Diff line
@@ -136,6 +136,7 @@ struct acpiphp_context { 
	struct acpiphp_func *func;

	struct acpiphp_bridge *bridge;

	unsigned int refcount;

	bool handler_for_func;

};



/*

drivers/pci/hotplug/acpiphp_glue.c

+52 −80
Original line number Diff line number Diff line
@@ -59,11 +59,10 @@ static DEFINE_MUTEX(acpiphp_context_lock); 


#define MY_NAME "acpiphp_glue"



static void handle_hotplug_event_bridge (acpi_handle, u32, void *);

static void handle_hotplug_event(acpi_handle handle, u32 type, void *data);

static void acpiphp_sanitize_bus(struct pci_bus *bus);

static void acpiphp_set_hpp_values(struct pci_bus *bus);

static void hotplug_event_func(acpi_handle handle, u32 type, void *context);

static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);

static void free_bridge(struct kref *kref);



/* callback routine to check for the existence of a pci dock device */
@@ -179,13 +178,13 @@ static void free_bridge(struct kref *kref) 
		kfree(slot);

	}



	context = bridge->context;

	/* Release the reference acquired by acpiphp_enumerate_slots(). */

	if ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)

	if (context->handler_for_func)

		put_bridge(bridge->func->slot->bridge);



	put_device(&bridge->pci_bus->dev);

	pci_dev_put(bridge->pci_dev);

	context = bridge->context;

	context->bridge = NULL;

	acpiphp_put_context(context);

	kfree(bridge);
@@ -414,12 +413,12 @@ static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data, 


	/* install notify handler */

	if (!(newfunc->flags & FUNC_HAS_DCK)) {

		status = acpi_install_notify_handler(handle,

					     ACPI_SYSTEM_NOTIFY,

					     handle_hotplug_event_func,

					     newfunc);



		if (ACPI_FAILURE(status))

		status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,

						     handle_hotplug_event,

						     context);

		if (ACPI_SUCCESS(status))

			context->handler_for_func = true;

		else

			err("failed to register interrupt notify handler\n");

	}
@@ -476,32 +475,23 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge) 
	acpi_status status;

	acpi_handle handle = bridge->handle;



	if (!pci_is_root_bus(bridge->pci_bus)) {

		status = acpi_remove_notify_handler(handle,

					    ACPI_SYSTEM_NOTIFY,

					    handle_hotplug_event_bridge);

	if (!bridge->context->handler_for_func) {

		status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,

						    handle_hotplug_event);

		if (ACPI_FAILURE(status))

			err("failed to remove notify handler\n");

	}



	if ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func) {

		status = acpi_install_notify_handler(bridge->func->handle,

						ACPI_SYSTEM_NOTIFY,

						handle_hotplug_event_func,

						bridge->func);

		if (ACPI_FAILURE(status))

			err("failed to install interrupt notify handler\n");

	}



	list_for_each_entry(slot, &bridge->slots, node) {

		list_for_each_entry(func, &slot->funcs, sibling) {

			if (is_dock_device(func->handle)) {

				unregister_hotplug_dock_device(func->handle);

			}

			if (!(func->flags & FUNC_HAS_DCK)) {

				func->context->handler_for_func = false;

				status = acpi_remove_notify_handler(func->handle,

							ACPI_SYSTEM_NOTIFY,

						handle_hotplug_event_func);

							handle_hotplug_event);

				if (ACPI_FAILURE(status))

					err("failed to remove notify handler\n");

			}
@@ -1071,31 +1061,6 @@ static void _handle_hotplug_event_bridge(struct work_struct *work) 
	put_bridge(bridge);

}



/**

 * handle_hotplug_event_bridge - handle ACPI event on bridges

 * @handle: Notify()'ed acpi_handle

 * @type: Notify code

 * @context: pointer to acpiphp_bridge structure

 *

 * Handles ACPI event notification on {host,p2p} bridges.

 */

static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,

					void *context)

{

	struct acpiphp_bridge *bridge = context;



	/*

	 * Currently the code adds all hotplug events to the kacpid_wq

	 * queue when it should add hotplug events to the kacpi_hotplug_wq.

	 * The proper way to fix this is to reorganize the code so that

	 * drivers (dock, etc.) do not call acpi_os_execute(), etc.

	 * For now just re-add this work to the kacpi_hotplug_wq so we

	 * don't deadlock on hotplug actions.

	 */

	get_bridge(bridge);

	alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_bridge);

}



static void hotplug_event_func(acpi_handle handle, u32 type, void *context)

{

	struct acpiphp_func *func = context;
@@ -1153,17 +1118,33 @@ static void _handle_hotplug_event_func(struct work_struct *work) 
}



/**

 * handle_hotplug_event_func - handle ACPI event on functions (i.e. slots)

 * handle_hotplug_event - handle ACPI hotplug event

 * @handle: Notify()'ed acpi_handle

 * @type: Notify code

 * @context: pointer to acpiphp_func structure

 * @data: pointer to acpiphp_context structure

 *

 * Handles ACPI event notification on slots.

 */

static void handle_hotplug_event_func(acpi_handle handle, u32 type,

				      void *context)

static void handle_hotplug_event(acpi_handle handle, u32 type, void *data)

{

	struct acpiphp_func *func = context;

	struct acpiphp_context *context;

	void (*work_func)(struct work_struct *work) = NULL;



	mutex_lock(&acpiphp_context_lock);

	context = acpiphp_get_context(handle);

	if (context) {

		if (context->bridge) {

			get_bridge(context->bridge);

			data = context->bridge;

			work_func = _handle_hotplug_event_bridge;

		} else if (context->func) {

			get_bridge(context->func->slot->bridge);

			data = context->func;

			work_func = _handle_hotplug_event_func;

		}

		acpiphp_put_context(context);

	}

	mutex_unlock(&acpiphp_context_lock);



	/*

	 * Currently the code adds all hotplug events to the kacpid_wq
@@ -1173,8 +1154,8 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type, 
	 * For now just re-add this work to the kacpi_hotplug_wq so we

	 * don't deadlock on hotplug actions.

	 */

	get_bridge(func->slot->bridge);

	alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);

	if (work_func)

		alloc_acpi_hp_work(handle, type, data, work_func);

}



/*
@@ -1245,34 +1226,25 @@ void acpiphp_enumerate_slots(struct pci_bus *bus) 
	if (pci_is_root_bus(bridge->pci_bus))

		return;



	/* install notify handler for P2P bridges */

	status = acpi_install_notify_handler(bridge->handle, ACPI_SYSTEM_NOTIFY,

					     handle_hotplug_event_bridge,

					     bridge);

	if (ACPI_FAILURE(status)) {

		acpi_handle_err(bridge->handle,

				"failed to register notify handler\n");

		goto err;

	}



	if (!acpi_has_method(bridge->handle, "_EJ0"))

		return;



	if (acpi_has_method(bridge->handle, "_EJ0")) {

		dbg("found ejectable p2p bridge\n");

		bridge->flags |= BRIDGE_HAS_EJ0;

	if (context->func) {

		get_bridge(context->func->slot->bridge);

	}

	if (context->handler_for_func) {

		/* Notify handler already installed. */

		bridge->func = context->func;

		handle = context->handle;

		WARN_ON(bridge->handle != handle);

		status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,

						    handle_hotplug_event_func);

		if (ACPI_FAILURE(status))

			acpi_handle_err(handle,

					"failed to remove notify handler\n");

		get_bridge(context->func->slot->bridge);

		return;

	}



	/* install notify handler for P2P bridges */

	status = acpi_install_notify_handler(bridge->handle, ACPI_SYSTEM_NOTIFY,

					     handle_hotplug_event, NULL);

	if (ACPI_SUCCESS(status))

		return;



	acpi_handle_err(bridge->handle, "failed to register notify handler\n");



 err:

	cleanup_bridge(bridge);

	put_bridge(bridge);