More ACPI support updates for 6.18-rc1

- Add missing synchronization between interface updates in the ACPI
    battery driver (Rafael Wysocki)
 
  - Remove open coded check for cpu_feature_enabled() from
    acpi_processor_power_init_bm_check() (Mario Limonciello)
 
  - Remove redundant rcu_read_lock/unlock() under spinlock from
    ghes_notify_hed() in the ACPI APEI support code (pengdonglin)
 
  - Make the .get_next_child_node() callback in the ACPI fwnode backend
    skip ACPI devices that are not present for consistency with the
    analogous callback in the OF fwnode backend (Sakari Ailus)
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Merge tag 'acpi-6.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more ACPI updates from Rafael Wysocki:
 "These fix a driver bug, clean up two pieces of code and improve the
  fwnode API consistency:

   - Add missing synchronization between interface updates in the ACPI
     battery driver (Rafael Wysocki)

   - Remove open coded check for cpu_feature_enabled() from
     acpi_processor_power_init_bm_check() (Mario Limonciello)

   - Remove redundant rcu_read_lock/unlock() under spinlock from
     ghes_notify_hed() in the ACPI APEI support code (pengdonglin)

   - Make the .get_next_child_node() callback in the ACPI fwnode backend
     skip ACPI devices that are not present for consistency with the
     analogous callback in the OF fwnode backend (Sakari Ailus)"

* tag 'acpi-6.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: property: Return present device nodes only on fwnode interface
  ACPI: APEI: Remove redundant rcu_read_lock/unlock() under spinlock
  ACPI: battery: Add synchronization between interface updates
  x86/acpi/cstate: Remove open coded check for cpu_feature_enabled()

arch/x86/kernel/acpi/cstate.c

@@ -89,7 +89,7 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 		 */
 		flags->bm_control = 0;
 	}
-	if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) {
+	if (cpu_feature_enabled(X86_FEATURE_ZEN)) {
 		/*
 		 * For all AMD Zen or newer CPUs that support C3, caches
 		 * should not be flushed by software while entering C3

drivers/acpi/apei/ghes.c

@@ -1207,12 +1207,10 @@ static int ghes_notify_hed(struct notifier_block *this, unsigned long event,
 	int ret = NOTIFY_DONE;
 
 	spin_lock_irqsave(&ghes_notify_lock_irq, flags);
-	rcu_read_lock();
 	list_for_each_entry_rcu(ghes, &ghes_hed, list) {
 		if (!ghes_proc(ghes))
 			ret = NOTIFY_OK;
 	}
-	rcu_read_unlock();
 	spin_unlock_irqrestore(&ghes_notify_lock_irq, flags);
 
 	return ret;

drivers/acpi/battery.c

@@ -92,7 +92,7 @@ enum {
 
 struct acpi_battery {
 	struct mutex lock;
-	struct mutex sysfs_lock;
+	struct mutex update_lock;
 	struct power_supply *bat;
 	struct power_supply_desc bat_desc;
 	struct acpi_device *device;
@@ -904,15 +904,12 @@ static int sysfs_add_battery(struct acpi_battery *battery)
 
 static void sysfs_remove_battery(struct acpi_battery *battery)
 {
-	mutex_lock(&battery->sysfs_lock);
+	if (!battery->bat)
-	if (!battery->bat) {
-		mutex_unlock(&battery->sysfs_lock);
 		return;
-	}
+
 	battery_hook_remove_battery(battery);
 	power_supply_unregister(battery->bat);
 	battery->bat = NULL;
-	mutex_unlock(&battery->sysfs_lock);
 }
 
 static void find_battery(const struct dmi_header *dm, void *private)
@@ -1072,6 +1069,9 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 
 	if (!battery)
 		return;
+
+	guard(mutex)(&battery->update_lock);
+
 	old = battery->bat;
 	/*
 	 * On Acer Aspire V5-573G notifications are sometimes triggered too
@@ -1094,21 +1094,22 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 }
 
 static int battery_notify(struct notifier_block *nb,
-			       unsigned long mode, void *_unused)
+			  unsigned long mode, void *_unused)
 {
 	struct acpi_battery *battery = container_of(nb, struct acpi_battery,
 						    pm_nb);
-	int result;
 
-	switch (mode) {
+	if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
-	case PM_POST_HIBERNATION:
+		guard(mutex)(&battery->update_lock);
-	case PM_POST_SUSPEND:
+
 		if (!acpi_battery_present(battery))
 			return 0;
 
 		if (battery->bat) {
 			acpi_battery_refresh(battery);
 		} else {
+			int result;
+
 			result = acpi_battery_get_info(battery);
 			if (result)
 				return result;
@@ -1120,7 +1121,6 @@ static int battery_notify(struct notifier_block *nb,
 
 		acpi_battery_init_alarm(battery);
 		acpi_battery_get_state(battery);
-		break;
 	}
 
 	return 0;
@@ -1198,6 +1198,8 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 {
 	int retry, ret;
 
+	guard(mutex)(&battery->update_lock);
+
 	for (retry = 5; retry; retry--) {
 		ret = acpi_battery_update(battery, false);
 		if (!ret)
@@ -1208,6 +1210,13 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 	return ret;
 }
 
+static void sysfs_battery_cleanup(struct acpi_battery *battery)
+{
+	guard(mutex)(&battery->update_lock);
+
+	sysfs_remove_battery(battery);
+}
+
 static int acpi_battery_add(struct acpi_device *device)
 {
 	int result = 0;
@@ -1230,7 +1239,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (result)
 		return result;
 
-	result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+	result = devm_mutex_init(&device->dev, &battery->update_lock);
 	if (result)
 		return result;
 
@@ -1262,7 +1271,7 @@ fail_pm:
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
 fail:
-	sysfs_remove_battery(battery);
+	sysfs_battery_cleanup(battery);
 
 	return result;
 }
@@ -1281,6 +1290,9 @@ static void acpi_battery_remove(struct acpi_device *device)
 
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
+
+	guard(mutex)(&battery->update_lock);
+
 	sysfs_remove_battery(battery);
 }
 
@@ -1297,6 +1309,9 @@ static int acpi_battery_resume(struct device *dev)
 		return -EINVAL;
 
 	battery->update_time = 0;
+
+	guard(mutex)(&battery->update_lock);
+
 	acpi_battery_update(battery, true);
 	return 0;
 }

drivers/acpi/property.c

@@ -1388,6 +1388,28 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode,
 	return NULL;
 }
 
+/*
+ * acpi_get_next_present_subnode - Return the next present child node handle
+ * @fwnode: Firmware node to find the next child node for.
+ * @child: Handle to one of the device's child nodes or a null handle.
+ *
+ * Like acpi_get_next_subnode(), but the device nodes returned by
+ * acpi_get_next_present_subnode() are guaranteed to be present.
+ *
+ * Returns: The fwnode handle of the next present sub-node.
+ */
+static struct fwnode_handle *
+acpi_get_next_present_subnode(const struct fwnode_handle *fwnode,
+			      struct fwnode_handle *child)
+{
+	do {
+		child = acpi_get_next_subnode(fwnode, child);
+	} while (is_acpi_device_node(child) &&
+		 !acpi_device_is_present(to_acpi_device_node(child)));
+
+	return child;
+}
+
 /**
  * acpi_node_get_parent - Return parent fwnode of this fwnode
  * @fwnode: Firmware node whose parent to get
@@ -1722,7 +1744,7 @@ static int acpi_fwnode_irq_get(const struct fwnode_handle *fwnode,
 		.property_read_string_array =				\
 			acpi_fwnode_property_read_string_array,		\
 		.get_parent = acpi_node_get_parent,			\
-		.get_next_child_node = acpi_get_next_subnode,		\
+		.get_next_child_node = acpi_get_next_present_subnode,	\
 		.get_named_child_node = acpi_fwnode_get_named_child_node, \
 		.get_name = acpi_fwnode_get_name,			\
 		.get_name_prefix = acpi_fwnode_get_name_prefix,		\