[PATCH] 2.6.24-rc2: fix oops in ACPI battery removal

[Andrey Borzenkov <arvidjaar@mail.ru>]

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Alexey, this fixes my patch that went into -rc2. Sorry for Oops.

Subject: [PATCH] 2.6.24-rc2: do not unregister power_supply in sysfs ->show method
From: Andrey Borzenkov <arvidjaar@mail.ru>

Currently unplugging battery oopses with call stack:

[ 2245.375393]  [<c010488a>] show_trace_log_lvl+0x1a/0x30
[ 2245.375570]  [<c0104949>] show_stack_log_lvl+0xa9/0xd0
[ 2245.375732]  [<c0104a36>] show_registers+0xc6/0x1c0
[ 2245.375884]  [<c0104c21>] die+0xf1/0x200
[ 2245.376014]  [<c02d2a58>] do_page_fault+0x198/0x690
[ 2245.376207]  [<c02d1522>] error_code+0x6a/0x70
[ 2245.376366]  [<c0243c20>] device_del+0x20/0x280
[ 2245.376530]  [<c0243e8b>] device_unregister+0xb/0x20
[ 2245.376686]  [<dfd7401a>] power_supply_unregister+0x1a/0x20 [power_supply]
[ 2245.376911]  [<dfd5f035>] sysfs_remove_battery+0x1f/0x22 [battery]
[ 2245.382969]  [<dfd5f1e6>] acpi_battery_update+0x42/0x293 [battery]
[ 2245.388862]  [<dfd5f5f5>] acpi_battery_get_property+0x34/0x16e [battery]
[ 2245.394770]  [<dfd74368>] power_supply_show_property+0x38/0x130 [power_supply]
[ 2245.400733]  [<dfd746f1>] power_supply_uevent+0x111/0x1c0 [power_supply]
[ 2245.406745]  [<c0244559>] dev_uevent+0x99/0x100
[ 2245.412744]  [<c01d37ff>] kobject_uevent_env+0x17f/0x3c0
[ 2245.418768]  [<c01d3a4a>] kobject_uevent+0xa/0x10
[ 2245.424732]  [<c0243da3>] device_del+0x1a3/0x280
[ 2245.430683]  [<c0243e8b>] device_unregister+0xb/0x20
[ 2245.436632]  [<dfd7401a>] power_supply_unregister+0x1a/0x20 [power_supply]
[ 2245.442670]  [<dfd5f035>] sysfs_remove_battery+0x1f/0x22 [battery]
[ 2245.448790]  [<dfd5f1e6>] acpi_battery_update+0x42/0x293 [battery]
[ 2245.454874]  [<dfd5f7ad>] acpi_battery_notify+0x1e/0x69 [battery]
[ 2245.460957]  [<c02086cd>] acpi_ev_notify_dispatch+0x4c/0x57
[ 2245.467077]  [<c0200d54>] acpi_os_execute_notify+0x24/0x2f
[ 2245.473167]  [<c012a431>] run_workqueue+0x161/0x1e0
[ 2245.479289]  [<c012ae5b>] worker_thread+0x8b/0xf0
[ 2245.485279]  [<c012e0b2>] kthread+0x42/0x70
[ 2245.491068]  [<c01044e3>] kernel_thread_helper+0x7/0x14

Do not try to (un-)register sysfs in acpi_battery_update - instead, do
it only on battery add or in notification handler.

On the way fix battery removal (reset device to NULL) and use proper
interface for sending change event (power_supply_changed) instead of
doing it directly.

Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>

---

 drivers/acpi/battery.c |   18 +++++++++---------
 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 1905b88..2810a9b 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -457,6 +457,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
 		return;
 	device_remove_file(battery->bat.dev, &alarm_attr);
 	power_supply_unregister(&battery->bat);
+	battery->bat.dev = NULL;
 }
 
 static int acpi_battery_update(struct acpi_battery *battery)
@@ -464,12 +465,6 @@ static int acpi_battery_update(struct acpi_battery *battery)
 	int result = acpi_battery_get_status(battery);
 	if (result)
 		return result;
-	if (!acpi_battery_present(battery)) {
-		sysfs_remove_battery(battery);
-		return 0;
-	}
-	if (!battery->bat.dev)
-		sysfs_add_battery(battery);
 	return acpi_battery_get_state(battery);
 }
 
@@ -758,14 +753,17 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 		return;
 	device = battery->device;
 	acpi_battery_update(battery);
+	if (!acpi_battery_present(battery))
+		sysfs_remove_battery(battery);
+	else if (!battery->bat.dev)
+		sysfs_add_battery(battery);
+	else
+		power_supply_changed(&battery->bat);
 	acpi_bus_generate_proc_event(device, event,
 				     acpi_battery_present(battery));
 	acpi_bus_generate_netlink_event(device->pnp.device_class,
 					device->dev.bus_id, event,
 					acpi_battery_present(battery));
-	/* acpi_batter_update could remove power_supply object */
-	if (battery->bat.dev)
-		kobject_uevent(&battery->bat.dev->kobj, KOBJ_CHANGE);
 }
 
 static int acpi_battery_add(struct acpi_device *device)
@@ -784,6 +782,8 @@ static int acpi_battery_add(struct acpi_device *device)
 	acpi_driver_data(device) = battery;
 	mutex_init(&battery->lock);
 	acpi_battery_update(battery);
+	if (acpi_battery_present(battery))
+		sysfs_add_battery(battery);
 #ifdef CONFIG_ACPI_PROCFS
 	result = acpi_battery_add_fs(device);
 	if (result)

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