[PATCH AUTOSEL 5.4 1/2] ACPI: battery: create alarm sysfs attribute atomically

[PATCH AUTOSEL 5.4 1/2] ACPI: battery: create alarm sysfs attribute atomically

[Sasha Levin]

From: Thomas Weißschuh <linux@weissschuh.net>

[ Upstream commit a231eed10ed5a290129fda36ad7bcc263c53ff7d ]

Let the power supply core register the attribute.
This ensures that the attribute is created before the device is
announced to userspace, avoid a race condition.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/battery.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index a49a09e3de1b3..af78f76a28729 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -681,12 +681,18 @@ static ssize_t acpi_battery_alarm_store(struct device *dev,
 	return count;
 }
 
-static const struct device_attribute alarm_attr = {
+static struct device_attribute alarm_attr = {
 	.attr = {.name = "alarm", .mode = 0644},
 	.show = acpi_battery_alarm_show,
 	.store = acpi_battery_alarm_store,
 };
 
+static struct attribute *acpi_battery_attrs[] = {
+	&alarm_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(acpi_battery);
+
 /*
  * The Battery Hooking API
  *
@@ -823,7 +829,10 @@ static void __exit battery_hook_exit(void)
 
 static int sysfs_add_battery(struct acpi_battery *battery)
 {
-	struct power_supply_config psy_cfg = { .drv_data = battery, };
+	struct power_supply_config psy_cfg = {
+		.drv_data = battery,
+		.attr_grp = acpi_battery_groups,
+	};
 	bool full_cap_broken = false;
 
 	if (!ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity) &&
@@ -868,7 +877,7 @@ static int sysfs_add_battery(struct acpi_battery *battery)
 		return result;
 	}
 	battery_hook_add_battery(battery);
-	return device_create_file(&battery->bat->dev, &alarm_attr);
+	return 0;
 }
 
 static void sysfs_remove_battery(struct acpi_battery *battery)
@@ -879,7 +888,6 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
 		return;
 	}
 	battery_hook_remove_battery(battery);
-	device_remove_file(&battery->bat->dev, &alarm_attr);
 	power_supply_unregister(battery->bat);
 	battery->bat = NULL;
 	mutex_unlock(&battery->sysfs_lock);
-- 
2.43.0

[PATCH AUTOSEL 5.4 2/2] ACPI: SBS: manage alarm sysfs attribute through psy core

[Sasha Levin]

From: Thomas Weißschuh <linux@weissschuh.net>

[ Upstream commit 6bad28cfc30988a845fb3f59a99f4b8a4ce8fe95 ]

Let the power supply core register the attribute.

This ensures that the attribute is created before the device is
announced to userspace, avoiding a race condition.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/sbs.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
index 6e88224f60f09..4aa55d8d43859 100644
--- a/drivers/acpi/sbs.c
+++ b/drivers/acpi/sbs.c
@@ -80,7 +80,6 @@ struct acpi_battery {
 	u16 spec;
 	u8 id;
 	u8 present:1;
-	u8 have_sysfs_alarm:1;
 };
 
 #define to_acpi_battery(x) power_supply_get_drvdata(x)
@@ -465,12 +464,18 @@ static ssize_t acpi_battery_alarm_store(struct device *dev,
 	return count;
 }
 
-static const struct device_attribute alarm_attr = {
+static struct device_attribute alarm_attr = {
 	.attr = {.name = "alarm", .mode = 0644},
 	.show = acpi_battery_alarm_show,
 	.store = acpi_battery_alarm_store,
 };
 
+static struct attribute *acpi_battery_attrs[] = {
+	&alarm_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(acpi_battery);
+
 /* --------------------------------------------------------------------------
                                  Driver Interface
    -------------------------------------------------------------------------- */
@@ -512,7 +517,10 @@ static int acpi_battery_read(struct acpi_battery *battery)
 static int acpi_battery_add(struct acpi_sbs *sbs, int id)
 {
 	struct acpi_battery *battery = &sbs->battery[id];
-	struct power_supply_config psy_cfg = { .drv_data = battery, };
+	struct power_supply_config psy_cfg = {
+		.drv_data = battery,
+		.attr_grp = acpi_battery_groups,
+	};
 	int result;
 
 	battery->id = id;
@@ -542,10 +550,6 @@ static int acpi_battery_add(struct acpi_sbs *sbs, int id)
 		goto end;
 	}
 
-	result = device_create_file(&battery->bat->dev, &alarm_attr);
-	if (result)
-		goto end;
-	battery->have_sysfs_alarm = 1;
       end:
 	printk(KERN_INFO PREFIX "%s [%s]: Battery Slot [%s] (battery %s)\n",
 	       ACPI_SBS_DEVICE_NAME, acpi_device_bid(sbs->device),
@@ -557,11 +561,8 @@ static void acpi_battery_remove(struct acpi_sbs *sbs, int id)
 {
 	struct acpi_battery *battery = &sbs->battery[id];
 
-	if (battery->bat) {
-		if (battery->have_sysfs_alarm)
-			device_remove_file(&battery->bat->dev, &alarm_attr);
+	if (battery->bat)
 		power_supply_unregister(battery->bat);
-	}
 }
 
 static int acpi_charger_add(struct acpi_sbs *sbs)
-- 
2.43.0