[PATCH v3 1/3] Use acpi_os_hotplug_execute() instead of alloc_acpi_hp_work().

[Tang Chen <tangchen@cn.fujitsu.com>]

Hi Yinghai,

alloc_acpi_hp_work() just puts the hutplug work onto kacpi_hotplug_wq.
As mentioned by Toshi Kani, this job has been done in acpi_os_hotplug_execute().
So we should use it instead of alloc_acpi_hp_work().

This patch adds a acpi_hp_cb_data struct, which encapsulates the hotplug
event notifier's parameters:
	struct acpi_hp_cb_data {
		acpi_handle handle;
		u32 type;
		void *context;
	};

And also a function alloc_acpi_hp_work(), which calls acpi_os_hotplug_execute()
to put the hotplug job onto kacpi_hotplug_wq.

This patch is based on Lu Yinghai's tree:
git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-split-pci-root-hp-2

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 drivers/acpi/osl.c                 |   28 ++++++++++++------------
 drivers/acpi/pci_root_hp.c         |   25 +++++++++++++++-------
 drivers/pci/hotplug/acpiphp_glue.c |   39 +++++++++++++++++++----------------
 include/acpi/acpiosxf.h            |    7 ++---
 4 files changed, 55 insertions(+), 44 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 311a921..d441b16 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -52,6 +52,7 @@
 #include <acpi/acpi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/processor.h>
+#include <acpi/acpiosxf.h>
 
 #define _COMPONENT		ACPI_OS_SERVICES
 ACPI_MODULE_NAME("osl");
@@ -1592,23 +1593,22 @@ void acpi_os_set_prepare_sleep(int (*func)(u8 sleep_state,
 	__acpi_os_prepare_sleep = func;
 }
 
-void alloc_acpi_hp_work(acpi_handle handle, u32 type, void *context,
-			void (*func)(struct work_struct *work))
+void acpi_hp_cb_execute(acpi_handle handle, u32 type, void *context,
+			acpi_osd_exec_callback function)
 {
-	struct acpi_hp_work *hp_work;
-	int ret;
+	acpi_status status;
+	struct acpi_hp_cb_data *cb_data;
 
-	hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
-	if (!hp_work)
+	cb_data = kmalloc(sizeof(struct acpi_hp_cb_data), GFP_KERNEL);
+	if (!cb_data)
 		return;
 
-	hp_work->handle = handle;
-	hp_work->type = type;
-	hp_work->context = context;
+	cb_data->handle = handle;
+	cb_data->type = type;
+	cb_data->context = context;
 
-	INIT_WORK(&hp_work->work, func);
-	ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
-	if (!ret)
-		kfree(hp_work);
+	status = acpi_os_hotplug_execute(function, cb_data);
+	if (ACPI_FAILURE(status))
+		kfree(cb_data);
 }
-EXPORT_SYMBOL(alloc_acpi_hp_work);
+EXPORT_SYMBOL(acpi_hp_cb_execute);
diff --git a/drivers/acpi/pci_root_hp.c b/drivers/acpi/pci_root_hp.c
index 7d427e6..2ff83f4 100644
--- a/drivers/acpi/pci_root_hp.c
+++ b/drivers/acpi/pci_root_hp.c
@@ -75,19 +75,20 @@ static void handle_root_bridge_removal(struct acpi_device *device)
 	acpi_bus_hot_remove_device(ej_event);
 }
 
-static void _handle_hotplug_event_root(struct work_struct *work)
+/* This function is of type acpi_osd_exec_callback */
+static void _handle_hotplug_event_root(void *context)
 {
 	struct acpi_pci_root *root;
 	char objname[64];
 	struct acpi_buffer buffer = { .length = sizeof(objname),
 				      .pointer = objname };
-	struct acpi_hp_work *hp_work;
+	struct acpi_hp_cb_data *cb_data;
 	acpi_handle handle;
 	u32 type;
 
-	hp_work = container_of(work, struct acpi_hp_work, work);
-	handle = hp_work->handle;
-	type = hp_work->type;
+	cb_data = (struct acpi_hp_cb_data *)context;
+	handle = cb_data->handle;
+	type = cb_data->type;
 
 	root = acpi_pci_find_root(handle);
 
@@ -124,14 +125,22 @@ static void _handle_hotplug_event_root(struct work_struct *work)
 		break;
 	}
 
-	kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
+	kfree(context); /* allocated in handle_hotplug_event_bridge */
 }
 
 static void handle_hotplug_event_root(acpi_handle handle, u32 type,
 					void *context)
 {
-	alloc_acpi_hp_work(handle, type, context,
-				_handle_hotplug_event_root);
+	/*
+	 * 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.
+	 */
+	acpi_hp_cb_execute(handle, type, context,
+			_handle_hotplug_event_root);
 }
 
 static bool acpi_is_root_bridge_object(acpi_handle handle)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 0833d2e..b30fc37 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -50,6 +50,8 @@
 #include <linux/slab.h>
 #include <linux/acpi.h>
 
+#include <acpi/acpiosxf.h>
+
 #include "../pci.h"
 #include "acpiphp.h"
 
@@ -1209,7 +1211,8 @@ check_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 	return AE_OK ;
 }
 
-static void _handle_hotplug_event_bridge(struct work_struct *work)
+/* This function is of type acpi_osd_exec_callback */
+static void _handle_hotplug_event_bridge(void *context)
 {
 	struct acpiphp_bridge *bridge;
 	char objname[64];
@@ -1217,13 +1220,13 @@ static void _handle_hotplug_event_bridge(struct work_struct *work)
 				      .pointer = objname };
 	struct acpi_device *device;
 	int num_sub_bridges = 0;
-	struct acpi_hp_work *hp_work;
+	struct acpi_hp_cb_data *cb_data;
 	acpi_handle handle;
 	u32 type;
 
-	hp_work = container_of(work, struct acpi_hp_work, work);
-	handle = hp_work->handle;
-	type = hp_work->type;
+	cb_data = (struct acpi_hp_cb_data *)context;
+	handle = cb_data->handle;
+	type = cb_data->type;
 
 	if (acpi_bus_get_device(handle, &device)) {
 		/* This bridge must have just been physically inserted */
@@ -1302,7 +1305,7 @@ static void _handle_hotplug_event_bridge(struct work_struct *work)
 	}
 
 out:
-	kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
+	kfree(context); /* allocated in handle_hotplug_event_bridge */
 }
 
 /**
@@ -1324,29 +1327,28 @@ static void handle_hotplug_event_bridge(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.
 	 */
-	alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_bridge);
+	acpi_hp_cb_execute(handle, type, context,
+				_handle_hotplug_event_bridge);
 }
 
-static void _handle_hotplug_event_func(struct work_struct *work)
+/* This function is of type acpi_osd_exec_callback */
+static void _handle_hotplug_event_func(void *context)
 {
 	struct acpiphp_func *func;
 	char objname[64];
 	struct acpi_buffer buffer = { .length = sizeof(objname),
 				      .pointer = objname };
-	struct acpi_hp_work *hp_work;
+	struct acpi_hp_cb_data *cb_data;
 	acpi_handle handle;
 	u32 type;
-	void *context;
 
-	hp_work = container_of(work, struct acpi_hp_work, work);
-	handle = hp_work->handle;
-	type = hp_work->type;
-	context = hp_work->context;
+	cb_data = (struct acpi_hp_cb_data *)context;
+	handle = cb_data->handle;
+	type = cb_data->type;
+	func = (struct acpiphp_func *)cb_data->context;
 
 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 
-	func = (struct acpiphp_func *)context;
-
 	switch (type) {
 	case ACPI_NOTIFY_BUS_CHECK:
 		/* bus re-enumerate */
@@ -1377,7 +1379,7 @@ static void _handle_hotplug_event_func(struct work_struct *work)
 		break;
 	}
 
-	kfree(hp_work); /* allocated in handle_hotplug_event_func */
+	kfree(context); /* allocated in handle_hotplug_event_func */
 }
 
 /**
@@ -1399,7 +1401,8 @@ 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.
 	 */
-	alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);
+	acpi_hp_cb_execute(handle, type, context,
+			_handle_hotplug_event_func);
 }
 
 static struct acpi_pci_driver acpi_pci_hp_driver = {
diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
index 9f68f69..8825891 100644
--- a/include/acpi/acpiosxf.h
+++ b/include/acpi/acpiosxf.h
@@ -194,14 +194,13 @@ void acpi_os_fixed_event_count(u32 fixed_event_number);
 /*
  * Threads and Scheduling
  */
-struct acpi_hp_work {
-	struct work_struct work;
+struct acpi_hp_cb_data {
 	acpi_handle handle;
 	u32 type;
 	void *context;
 };
-void alloc_acpi_hp_work(acpi_handle handle, u32 type, void *context,
-			void (*func)(struct work_struct *work));
+void acpi_hp_cb_execute(acpi_handle handle, u32 type, void *context,
+			acpi_osd_exec_callback function);
 
 acpi_thread_id acpi_os_get_thread_id(void);
 
-- 
1.7.1