ACPI: battery: Simplify battery hook locking

[ 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>

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 44ca989f164661d55cc2316209df1cc6eb1c246d..04610036e5dc5f1c68e0dd58fc30d082463c73bc 100644 (file)
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -703,28 +703,28 @@ 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) {
                if (!hook->remove_battery(battery->bat, hook))
                        power_supply_changed(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);
 
@@ -750,7 +750,7 @@ 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;
                }
 
@@ -789,7 +789,7 @@ 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);
@@ -822,7 +822,7 @@ 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);
 }