4.19-stable review patch. If anyone has any objections, please let me know.
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From: Armin Wolf W_Armin@gmx.de
[ Upstream commit 86309cbed26139e1caae7629dcca1027d9a28e75 ]
Move the conditional locking from __battery_hook_unregister() into battery_hook_unregister() and rename the low-level function to simplify the locking during battery hook removal.
Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Pali Rohár pali@kernel.org Signed-off-by: Armin Wolf W_Armin@gmx.de Link: https://patch.msgid.link/20241001212835.341788-2-W_Armin@gmx.de Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Stable-dep-of: 76959aff14a0 ("ACPI: battery: Fix possible crash when unregistering a battery hook") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/battery.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index 88f4040d6c1f2..b741ed87ab3db 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -713,27 +713,27 @@ static LIST_HEAD(acpi_battery_list); static LIST_HEAD(battery_hook_list); static DEFINE_MUTEX(hook_mutex);
-static void __battery_hook_unregister(struct acpi_battery_hook *hook, int lock) +static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook) { struct acpi_battery *battery; + /* * In order to remove a hook, we first need to * de-register all the batteries that are registered. */ - if (lock) - mutex_lock(&hook_mutex); list_for_each_entry(battery, &acpi_battery_list, list) { hook->remove_battery(battery->bat); } list_del(&hook->list); - if (lock) - mutex_unlock(&hook_mutex); + pr_info("extension unregistered: %s\n", hook->name); }
void battery_hook_unregister(struct acpi_battery_hook *hook) { - __battery_hook_unregister(hook, 1); + mutex_lock(&hook_mutex); + battery_hook_unregister_unlocked(hook); + mutex_unlock(&hook_mutex); } EXPORT_SYMBOL_GPL(battery_hook_unregister);
@@ -759,7 +759,7 @@ void battery_hook_register(struct acpi_battery_hook *hook) * hooks. */ pr_err("extension failed to load: %s", hook->name); - __battery_hook_unregister(hook, 0); + battery_hook_unregister_unlocked(hook); goto end; } } @@ -796,7 +796,7 @@ static void battery_hook_add_battery(struct acpi_battery *battery) */ pr_err("error in extension, unloading: %s", hook_node->name); - __battery_hook_unregister(hook_node, 0); + battery_hook_unregister_unlocked(hook_node); } } mutex_unlock(&hook_mutex); @@ -829,7 +829,7 @@ static void __exit battery_hook_exit(void) * need to remove the hooks. */ list_for_each_entry_safe(hook, ptr, &battery_hook_list, list) { - __battery_hook_unregister(hook, 1); + battery_hook_unregister(hook); } mutex_destroy(&hook_mutex); }