ACPI: driver: Do not set acpi_device_class() unnecessarily

rafaeljw · rafaeljw · commit e18947038bf4 · 2026-03-13T16:48:26.000+01:00
Several core ACPI device drivers set acpi_device_class() for the given struct acpi_device to whatever they like, but that value is never used unless the driver itself uses it and, sadly, they neglect to clear it on remove. Since the only one of them still using acpi_device_class() after previous changes is the button driver, update the others to stop setting it in vain. Also drop the related device class sybmols that become redundant. Since the ACPI button driver continues to use acpi_device_class(), make it clear the struct field represented by acpi_device_class() in its remove callback. No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/3706295.iIbC2pHGDl@rafael.j.wysocki
diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
@@ -203,7 +203,6 @@ static int acpi_ac_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ac->device = adev;
-	strscpy(acpi_device_class(adev), ACPI_AC_CLASS);
 
 	platform_set_drvdata(pdev, ac);
 
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
@@ -18,7 +18,6 @@
 
 #include "internal.h"
 
-#define ACPI_MEMORY_DEVICE_CLASS		"memory"
 #define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
 
 static const struct acpi_device_id memory_device_ids[] = {
@@ -296,7 +295,6 @@ static int acpi_memory_device_add(struct acpi_device *device,
 	INIT_LIST_HEAD(&mem_device->res_list);
 	mem_device->device = device;
 	mem_device->mgid = -1;
-	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 	device->driver_data = mem_device;
 
 	/* Get the range from the _CRS */
diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
@@ -23,7 +23,6 @@
 #include <asm/mwait.h>
 #include <xen/xen.h>
 
-#define ACPI_PROCESSOR_AGGREGATOR_CLASS	"acpi_pad"
 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
 
 #define ACPI_PROCESSOR_AGGREGATOR_STATUS_SUCCESS	0
@@ -413,7 +412,7 @@ static void acpi_pad_notify(acpi_handle handle, u32 event, void *data)
 	switch (event) {
 	case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
 		acpi_pad_handle_notify(handle);
-		acpi_bus_generate_netlink_event(ACPI_PROCESSOR_AGGREGATOR_CLASS,
+		acpi_bus_generate_netlink_event("acpi_pad",
 						dev_name(&adev->dev), event, 0);
 		break;
 	default:
@@ -426,8 +425,6 @@ static int acpi_pad_probe(struct platform_device *pdev)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 
-	strscpy(acpi_device_class(adev), ACPI_PROCESSOR_AGGREGATOR_CLASS);
-
 	return acpi_dev_install_notify_handler(adev, ACPI_DEVICE_NOTIFY,
 					       acpi_pad_notify, adev);
 }
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
@@ -438,7 +438,6 @@ static int acpi_processor_add(struct acpi_device *device,
 	}
 
 	pr->handle = device->handle;
-	strscpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
 	device->driver_data = pr;
 
 	result = acpi_processor_get_info(device);
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
@@ -1141,8 +1141,6 @@ static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
 		return -ENOMEM;
 	}
 
-	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
-
 	data->device_id = device_id;
 	data->video = video;
 	data->dev = device;
@@ -2018,7 +2016,6 @@ static int acpi_video_bus_probe(struct auxiliary_device *aux_dev,
 	auxiliary_set_drvdata(aux_dev, video);
 
 	video->device = device;
-	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
 	device->driver_data = video;
 
 	acpi_video_bus_find_cap(video);
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
@@ -1228,7 +1228,6 @@ static int acpi_battery_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, battery);
 
 	battery->device = device;
-	strscpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
 
 	result = devm_mutex_init(&pdev->dev, &battery->update_lock);
 	if (result)
diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
@@ -697,6 +697,8 @@ static void acpi_button_remove(struct platform_device *pdev)
 	acpi_button_remove_fs(button);
 	input_unregister_device(button->input);
 	kfree(button);
+
+	memset(acpi_device_class(adev), 0, sizeof(acpi_device_class));
 }
 
 static int param_set_lid_init_state(const char *val,
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
@@ -35,8 +35,6 @@
 
 #include "internal.h"
 
-#define ACPI_EC_CLASS			"embedded_controller"
-
 /* EC status register */
 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
@@ -1680,8 +1678,6 @@ static int acpi_ec_probe(struct platform_device *pdev)
 	struct acpi_ec *ec;
 	int ret;
 
-	strscpy(acpi_device_class(device), ACPI_EC_CLASS);
-
 	if (boot_ec && (boot_ec->handle == device->handle ||
 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
 		/* Fast path: this device corresponds to the boot EC. */
diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
@@ -29,7 +29,6 @@
 
 #include "internal.h"
 
-#define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
 #define ACPI_PCI_LINK_MAX_POSSIBLE	16
 
 static int acpi_pci_link_add(struct acpi_device *device,
@@ -724,7 +723,6 @@ static int acpi_pci_link_add(struct acpi_device *device,
 		return -ENOMEM;
 
 	link->device = device;
-	strscpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 	device->driver_data = link;
 
 	mutex_lock(&acpi_link_lock);
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
@@ -24,7 +24,6 @@
 #include <linux/platform_data/x86/apple.h>
 #include "internal.h"
 
-#define ACPI_PCI_ROOT_CLASS		"pci_bridge"
 static int acpi_pci_root_add(struct acpi_device *device,
 			     const struct acpi_device_id *not_used);
 static void acpi_pci_root_remove(struct acpi_device *device);
@@ -688,7 +687,6 @@ static int acpi_pci_root_add(struct acpi_device *device,
 
 	root->device = device;
 	root->segment = segment & 0xFFFF;
-	strscpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 	device->driver_data = root;
 
 	if (hotadd && dmar_device_add(handle)) {
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
@@ -37,7 +37,6 @@
 #include "sleep.h"
 #include "internal.h"
 
-#define ACPI_POWER_CLASS		"power_resource"
 #define ACPI_POWER_RESOURCE_STATE_OFF	0x00
 #define ACPI_POWER_RESOURCE_STATE_ON	0x01
 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
@@ -954,7 +953,6 @@ struct acpi_device *acpi_add_power_resource(acpi_handle handle)
 	mutex_init(&resource->resource_lock);
 	INIT_LIST_HEAD(&resource->list_node);
 	INIT_LIST_HEAD(&resource->dependents);
-	strscpy(acpi_device_class(device), ACPI_POWER_CLASS);
 	device->power.state = ACPI_STATE_UNKNOWN;
 	device->flags.match_driver = true;
 
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
@@ -85,8 +85,8 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 		return;
 	}
 
-	acpi_bus_generate_netlink_event(ACPI_PROCESSOR_CLASS,
-					dev_name(&device->dev), event, ev_data);
+	acpi_bus_generate_netlink_event("processor", dev_name(&device->dev),
+					event, ev_data);
 }
 
 static int __acpi_processor_start(struct acpi_device *device);
diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
@@ -26,7 +26,6 @@
 
 #include "sbshc.h"
 
-#define ACPI_SBS_CLASS			"sbs"
 #define ACPI_AC_CLASS			"ac_adapter"
 #define ACPI_SBS_DEVICE_NAME		"Smart Battery System"
 #define ACPI_BATTERY_DIR_NAME		"BAT%i"
@@ -648,7 +647,6 @@ static int acpi_sbs_probe(struct platform_device *pdev)
 
 	sbs->hc = dev_get_drvdata(pdev->dev.parent);
 	sbs->device = device;
-	strscpy(acpi_device_class(device), ACPI_SBS_CLASS);
 
 	result = acpi_charger_add(sbs);
 	if (result && result != -ENODEV)
diff --git a/drivers/acpi/sbshc.c b/drivers/acpi/sbshc.c
@@ -18,8 +18,6 @@
 #include "sbshc.h"
 #include "internal.h"
 
-#define ACPI_SMB_HC_CLASS	"smbus_host_ctl"
-
 struct acpi_smb_hc {
 	struct acpi_ec *ec;
 	struct mutex lock;
@@ -250,8 +248,6 @@ static int acpi_smbus_hc_probe(struct platform_device *pdev)
 		return -EIO;
 	}
 
-	strscpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
-
 	hc = kzalloc_obj(struct acpi_smb_hc);
 	if (!hc)
 		return -ENOMEM;
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
@@ -799,7 +799,6 @@ static int acpi_thermal_probe(struct platform_device *pdev)
 
 	tz->device = device;
 	strscpy(tz->name, device->pnp.bus_id);
-	strscpy(acpi_device_class(device), ACPI_THERMAL_CLASS);
 
 	acpi_thermal_aml_dependency_fix(tz);
 
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
@@ -14,7 +14,6 @@
 
 #include <asm/acpi.h>
 
-#define ACPI_PROCESSOR_CLASS		"processor"
 #define ACPI_PROCESSOR_DEVICE_HID	"ACPI0007"
 #define ACPI_PROCESSOR_CONTAINER_HID	"ACPI0010"
 

Original file line number	Diff line number	Diff line change
`@@ -438,7 +438,6 @@ static int acpi_processor_add(struct acpi_device *device,`
`438`	`438`	`}`
`439`	`439`
`440`	`440`	`pr->handle = device->handle;`
`441`		`- strscpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);`
`442`	`441`	`device->driver_data = pr;`
`443`	`442`
`444`	`443`	`result = acpi_processor_get_info(device);`
Original file line number	Diff line number	Diff line change
`@@ -697,6 +697,8 @@ static void acpi_button_remove(struct platform_device *pdev)`
`697`	`697`	`acpi_button_remove_fs(button);`
`698`	`698`	`input_unregister_device(button->input);`
`699`	`699`	`kfree(button);`
	`700`	`+`
	`701`	`+ memset(acpi_device_class(adev), 0, sizeof(acpi_device_class));`
`700`	`702`	`}`
`701`	`703`
`702`	`704`	`static int param_set_lid_init_state(const char *val,`