Driver core changes for 6.10-rc1

Here is the small set of driver core and kernfs changes for 6.10-rc1.
 
 Nothing major here at all, just a small set of changes for some driver
 core apis, and minor fixups.  Included in here are:
   - sysfs_bin_attr_simple_read() helper added and used
   - device_show_string() helper added and used
 All usages of these were acked by the various maintainers.  Also in here
 are:
   - kernfs minor cleanup
   - removed unused functions
   - typo fix in documentation
   - pay attention to sysfs_create_link() failures in module.c finally.
 
 All of these have been in linux-next for a very long time with no
 reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the small set of driver core and kernfs changes for 6.10-rc1.

  Nothing major here at all, just a small set of changes for some driver
  core apis, and minor fixups. Included in here are:

   - sysfs_bin_attr_simple_read() helper added and used

   - device_show_string() helper added and used

  All usages of these were acked by the various maintainers. Also in
  here are:

   - kernfs minor cleanup

   - removed unused functions

   - typo fix in documentation

   - pay attention to sysfs_create_link() failures in module.c finally

  All of these have been in linux-next for a very long time with no
  reported problems"

* tag 'driver-core-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  device property: Fix a typo in the description of device_get_child_node_count()
  kernfs: mount: Remove unnecessary ‘NULL’ values from knparent
  scsi: Use device_show_string() helper for sysfs attributes
  platform/x86: Use device_show_string() helper for sysfs attributes
  perf: Use device_show_string() helper for sysfs attributes
  IB/qib: Use device_show_string() helper for sysfs attributes
  hwmon: Use device_show_string() helper for sysfs attributes
  driver core: Add device_show_string() helper for sysfs attributes
  treewide: Use sysfs_bin_attr_simple_read() helper
  sysfs: Add sysfs_bin_attr_simple_read() helper
  module: don't ignore sysfs_create_link() failures
  driver core: Remove unused platform_notify, platform_notify_remove

arch/powerpc/perf/hv-24x7.c

@@ -425,16 +425,6 @@ static char *memdup_to_str(char *maybe_str, int max_len, gfp_t gfp)
 	return kasprintf(gfp, "%.*s", max_len, maybe_str);
 }
 
-static ssize_t device_show_string(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *d;
-
-	d = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sprintf(buf, "%s\n", (char *)d->var);
-}
-
 static ssize_t cpumask_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {

arch/powerpc/platforms/powernv/opal.c

@@ -792,14 +792,6 @@ static int __init opal_sysfs_init(void)
 	return 0;
 }
 
-static ssize_t export_attr_read(struct file *fp, struct kobject *kobj,
-				struct bin_attribute *bin_attr, char *buf,
-				loff_t off, size_t count)
-{
-	return memory_read_from_buffer(buf, count, &off, bin_attr->private,
-				       bin_attr->size);
-}
-
 static int opal_add_one_export(struct kobject *parent, const char *export_name,
 			       struct device_node *np, const char *prop_name)
 {
@@ -826,7 +818,7 @@ static int opal_add_one_export(struct kobject *parent, const char *export_name,
 	sysfs_bin_attr_init(attr);
 	attr->attr.name = name;
 	attr->attr.mode = 0400;
-	attr->read = export_attr_read;
+	attr->read = sysfs_bin_attr_simple_read;
 	attr->private = __va(vals[0]);
 	attr->size = vals[1];
 

arch/x86/events/intel/core.c

@@ -5645,18 +5645,11 @@ lbr_is_visible(struct kobject *kobj, struct attribute *attr, int i)
 
 static char pmu_name_str[30];
 
-static ssize_t pmu_name_show(struct device *cdev,
+static DEVICE_STRING_ATTR_RO(pmu_name, 0444, pmu_name_str);
-			     struct device_attribute *attr,
-			     char *buf)
-{
-	return snprintf(buf, PAGE_SIZE, "%s\n", pmu_name_str);
-}
-
-static DEVICE_ATTR_RO(pmu_name);
 
 static struct attribute *intel_pmu_caps_attrs[] = {
-       &dev_attr_pmu_name.attr,
+	&dev_attr_pmu_name.attr.attr,
-       NULL
+	NULL
 };
 
 static DEVICE_ATTR(allow_tsx_force_abort, 0644,

drivers/acpi/bgrt.c

@@ -29,14 +29,7 @@ BGRT_SHOW(type, image_type);
 BGRT_SHOW(xoffset, image_offset_x);
 BGRT_SHOW(yoffset, image_offset_y);
 
-static ssize_t image_read(struct file *file, struct kobject *kobj,
+static BIN_ATTR_SIMPLE_RO(image);
-	       struct bin_attribute *attr, char *buf, loff_t off, size_t count)
-{
-	memcpy(buf, attr->private + off, count);
-	return count;
-}
-
-static BIN_ATTR_RO(image, 0);	/* size gets filled in later */
 
 static struct attribute *bgrt_attributes[] = {
 	&bgrt_attr_version.attr,

drivers/base/base.h

@@ -192,11 +192,14 @@ extern struct kset *devices_kset;
 void devices_kset_move_last(struct device *dev);
 
 #if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
-void module_add_driver(struct module *mod, struct device_driver *drv);
+int module_add_driver(struct module *mod, struct device_driver *drv);
 void module_remove_driver(struct device_driver *drv);
 #else
-static inline void module_add_driver(struct module *mod,
+static inline int module_add_driver(struct module *mod,
-				     struct device_driver *drv) { }
+				    struct device_driver *drv)
+{
+	return 0;
+}
 static inline void module_remove_driver(struct device_driver *drv) { }
 #endif
 

drivers/base/bus.c

@@ -674,7 +674,12 @@ int bus_add_driver(struct device_driver *drv)
 		if (error)
 			goto out_del_list;
 	}
-	module_add_driver(drv->owner, drv);
+	error = module_add_driver(drv->owner, drv);
+	if (error) {
+		printk(KERN_ERR "%s: failed to create module links for %s\n",
+			__func__, drv->name);
+		goto out_detach;
+	}
 
 	error = driver_create_file(drv, &driver_attr_uevent);
 	if (error) {
@@ -699,6 +704,8 @@ int bus_add_driver(struct device_driver *drv)
 
 	return 0;
 
+out_detach:
+	driver_detach(drv);
 out_del_list:
 	klist_del(&priv->knode_bus);
 out_unregister:

drivers/base/core.c

@@ -2346,8 +2346,6 @@ static void fw_devlink_link_device(struct device *dev)
 
 /* Device links support end. */
 
-int (*platform_notify)(struct device *dev) = NULL;
-int (*platform_notify_remove)(struct device *dev) = NULL;
 static struct kobject *dev_kobj;
 
 /* /sys/dev/char */
@@ -2395,16 +2393,10 @@ static void device_platform_notify(struct device *dev)
 	acpi_device_notify(dev);
 
 	software_node_notify(dev);
-
-	if (platform_notify)
-		platform_notify(dev);
 }
 
 static void device_platform_notify_remove(struct device *dev)
 {
-	if (platform_notify_remove)
-		platform_notify_remove(dev);
-
 	software_node_notify_remove(dev);
 
 	acpi_device_notify_remove(dev);
@@ -2546,6 +2538,15 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 }
 EXPORT_SYMBOL_GPL(device_show_bool);
 
+ssize_t device_show_string(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+
+	return sysfs_emit(buf, "%s\n", (char *)ea->var);
+}
+EXPORT_SYMBOL_GPL(device_show_string);
+
 /**
  * device_release - free device structure.
  * @kobj: device's kobject.

drivers/base/module.c

@@ -30,14 +30,14 @@ static void module_create_drivers_dir(struct module_kobject *mk)
 	mutex_unlock(&drivers_dir_mutex);
 }
 
-void module_add_driver(struct module *mod, struct device_driver *drv)
+int module_add_driver(struct module *mod, struct device_driver *drv)
 {
 	char *driver_name;
-	int no_warn;
 	struct module_kobject *mk = NULL;
+	int ret;
 
 	if (!drv)
-		return;
+		return 0;
 
 	if (mod)
 		mk = &mod->mkobj;
@@ -56,17 +56,37 @@ void module_add_driver(struct module *mod, struct device_driver *drv)
 	}
 
 	if (!mk)
-		return;
+		return 0;
+
+	ret = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
+	if (ret)
+		return ret;
 
-	/* Don't check return codes; these calls are idempotent */
-	no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
 	driver_name = make_driver_name(drv);
-	if (driver_name) {
+	if (!driver_name) {
-		module_create_drivers_dir(mk);
+		ret = -ENOMEM;
-		no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
+		goto out;
-					    driver_name);
-		kfree(driver_name);
 	}
+
+	module_create_drivers_dir(mk);
+	if (!mk->drivers_dir) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, driver_name);
+	if (ret)
+		goto out;
+
+	kfree(driver_name);
+
+	return 0;
+out:
+	sysfs_remove_link(&drv->p->kobj, "module");
+	sysfs_remove_link(mk->drivers_dir, driver_name);
+	kfree(driver_name);
+
+	return ret;
 }
 
 void module_remove_driver(struct device_driver *drv)

drivers/base/property.c

@@ -905,7 +905,7 @@ EXPORT_SYMBOL_GPL(fwnode_device_is_available);
 
 /**
  * device_get_child_node_count - return the number of child nodes for device
- * @dev: Device to cound the child nodes for
+ * @dev: Device to count the child nodes for
  *
  * Return: the number of child nodes for a given device.
  */

drivers/firmware/dmi_scan.c

@@ -761,16 +761,8 @@ static void __init dmi_scan_machine(void)
 	pr_info("DMI not present or invalid.\n");
 }
 
-static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
+static BIN_ATTR_SIMPLE_ADMIN_RO(smbios_entry_point);
-			      struct bin_attribute *attr, char *buf,
+static BIN_ATTR_SIMPLE_ADMIN_RO(DMI);
-			      loff_t pos, size_t count)
-{
-	memcpy(buf, attr->private + pos, count);
-	return count;
-}
-
-static BIN_ATTR(smbios_entry_point, S_IRUSR, raw_table_read, NULL, 0);
-static BIN_ATTR(DMI, S_IRUSR, raw_table_read, NULL, 0);
 
 static int __init dmi_init(void)
 {

drivers/firmware/efi/rci2-table.c

@@ -40,15 +40,7 @@ static u8 *rci2_base;
 static u32 rci2_table_len;
 unsigned long rci2_table_phys __ro_after_init = EFI_INVALID_TABLE_ADDR;
 
-static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
+static BIN_ATTR_SIMPLE_ADMIN_RO(rci2);
-			      struct bin_attribute *attr, char *buf,
-			      loff_t pos, size_t count)
-{
-	memcpy(buf, attr->private + pos, count);
-	return count;
-}
-
-static BIN_ATTR(rci2, S_IRUSR, raw_table_read, NULL, 0);
 
 static u16 checksum(void)
 {

drivers/gpu/drm/i915/gvt/firmware.c

@@ -51,21 +51,7 @@ struct gvt_firmware_header {
 
 #define dev_to_drm_minor(d) dev_get_drvdata((d))
 
-static ssize_t
+static BIN_ATTR_SIMPLE_ADMIN_RO(gvt_firmware);
-gvt_firmware_read(struct file *filp, struct kobject *kobj,
-	     struct bin_attribute *attr, char *buf,
-	     loff_t offset, size_t count)
-{
-	memcpy(buf, attr->private + offset, count);
-	return count;
-}
-
-static struct bin_attribute firmware_attr = {
-	.attr = {.name = "gvt_firmware", .mode = (S_IRUSR)},
-	.read = gvt_firmware_read,
-	.write = NULL,
-	.mmap = NULL,
-};
 
 static int expose_firmware_sysfs(struct intel_gvt *gvt)
 {
@@ -108,10 +94,10 @@ static int expose_firmware_sysfs(struct intel_gvt *gvt)
 	crc32_start = offsetof(struct gvt_firmware_header, version);
 	h->crc32 = crc32_le(0, firmware + crc32_start, size - crc32_start);
 
-	firmware_attr.size = size;
+	bin_attr_gvt_firmware.size = size;
-	firmware_attr.private = firmware;
+	bin_attr_gvt_firmware.private = firmware;
 
-	ret = device_create_bin_file(&pdev->dev, &firmware_attr);
+	ret = device_create_bin_file(&pdev->dev, &bin_attr_gvt_firmware);
 	if (ret) {
 		vfree(firmware);
 		return ret;
@@ -123,8 +109,8 @@ static void clean_firmware_sysfs(struct intel_gvt *gvt)
 {
 	struct pci_dev *pdev = to_pci_dev(gvt->gt->i915->drm.dev);
 
-	device_remove_bin_file(&pdev->dev, &firmware_attr);
+	device_remove_bin_file(&pdev->dev, &bin_attr_gvt_firmware);
-	vfree(firmware_attr.private);
+	vfree(bin_attr_gvt_firmware.private);
 }
 
 /**

drivers/hwmon/i5k_amb.c

@@ -101,14 +101,7 @@ struct i5k_amb_data {
 	unsigned int num_attrs;
 };
 
-static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
+static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);
-			 char *buf)
-{
-	return sprintf(buf, "%s\n", DRVNAME);
-}
-
-
-static DEVICE_ATTR_RO(name);
 
 static struct platform_device *amb_pdev;
 
@@ -373,7 +366,7 @@ static int i5k_amb_hwmon_init(struct platform_device *pdev)
 		}
 	}
 
-	res = device_create_file(&pdev->dev, &dev_attr_name);
+	res = device_create_file(&pdev->dev, &dev_attr_name.attr);
 	if (res)
 		goto exit_remove;
 
@@ -386,7 +379,7 @@ static int i5k_amb_hwmon_init(struct platform_device *pdev)
 	return res;
 
 exit_remove:
-	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_name.attr);
 	for (i = 0; i < data->num_attrs; i++)
 		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
 	kfree(data->attrs);
@@ -561,7 +554,7 @@ static void i5k_amb_remove(struct platform_device *pdev)
 	struct i5k_amb_data *data = platform_get_drvdata(pdev);
 
 	hwmon_device_unregister(data->hwmon_dev);
-	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_name.attr);
 	for (i = 0; i < data->num_attrs; i++)
 		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
 	kfree(data->attrs);

drivers/hwmon/ibmpex.c

@@ -256,12 +256,7 @@ static struct ibmpex_bmc_data *get_bmc_data(int iface)
 	return NULL;
 }
 
-static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
+static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);
-			 char *buf)
-{
-	return sprintf(buf, "%s\n", DRVNAME);
-}
-static SENSOR_DEVICE_ATTR_RO(name, name, 0);
 
 static ssize_t ibmpex_show_sensor(struct device *dev,
 				  struct device_attribute *devattr,
@@ -415,8 +410,7 @@ static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
 	if (err)
 		goto exit_remove;
 
-	err = device_create_file(data->bmc_device,
+	err = device_create_file(data->bmc_device, &dev_attr_name.attr);
-			&sensor_dev_attr_name.dev_attr);
 	if (err)
 		goto exit_remove;
 
@@ -425,7 +419,7 @@ static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
 exit_remove:
 	device_remove_file(data->bmc_device,
 			   &sensor_dev_attr_reset_high_low.dev_attr);
-	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
+	device_remove_file(data->bmc_device, &dev_attr_name.attr);
 	for (i = 0; i < data->num_sensors; i++)
 		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
 			if (!data->sensors[i].attr[j].dev_attr.attr.name)
@@ -516,7 +510,7 @@ static void ibmpex_bmc_delete(struct ibmpex_bmc_data *data)
 
 	device_remove_file(data->bmc_device,
 			   &sensor_dev_attr_reset_high_low.dev_attr);
-	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
+	device_remove_file(data->bmc_device, &dev_attr_name.attr);
 	for (i = 0; i < data->num_sensors; i++)
 		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
 			if (!data->sensors[i].attr[j].dev_attr.attr.name)

drivers/infiniband/hw/qib/qib.h

@@ -1359,7 +1359,6 @@ static inline u32 qib_get_rcvhdrtail(const struct qib_ctxtdata *rcd)
  * sysfs interface.
  */
 
-extern const char ib_qib_version[];
 extern const struct attribute_group qib_attr_group;
 extern const struct attribute_group *qib_attr_port_groups[];
 

drivers/infiniband/hw/qib/qib_driver.c

@@ -44,12 +44,6 @@
 
 #include "qib.h"
 
-/*
- * The size has to be longer than this string, so we can append
- * board/chip information to it in the init code.
- */
-const char ib_qib_version[] = QIB_DRIVER_VERSION "\n";
-
 DEFINE_MUTEX(qib_mutex);	/* general driver use */
 
 unsigned qib_ibmtu;

drivers/infiniband/hw/qib/qib_sysfs.c

@@ -585,13 +585,7 @@ static ssize_t hca_type_show(struct device *device,
 static DEVICE_ATTR_RO(hca_type);
 static DEVICE_ATTR(board_id, 0444, hca_type_show, NULL);
 
-static ssize_t version_show(struct device *device,
+static DEVICE_STRING_ATTR_RO(version, 0444, QIB_DRIVER_VERSION);
-			    struct device_attribute *attr, char *buf)
-{
-	/* The string printed here is already newline-terminated. */
-	return sysfs_emit(buf, "%s", (char *)ib_qib_version);
-}
-static DEVICE_ATTR_RO(version);
 
 static ssize_t boardversion_show(struct device *device,
 				 struct device_attribute *attr, char *buf)
@@ -721,7 +715,7 @@ static struct attribute *qib_attributes[] = {
 	&dev_attr_hw_rev.attr,
 	&dev_attr_hca_type.attr,
 	&dev_attr_board_id.attr,
-	&dev_attr_version.attr,
+	&dev_attr_version.attr.attr,
 	&dev_attr_nctxts.attr,
 	&dev_attr_nfreectxts.attr,
 	&dev_attr_serial.attr,

drivers/perf/alibaba_uncore_drw_pmu.c

@@ -236,24 +236,16 @@ static const struct attribute_group ali_drw_pmu_cpumask_attr_group = {
 	.attrs = ali_drw_pmu_cpumask_attrs,
 };
 
-static ssize_t ali_drw_pmu_identifier_show(struct device *dev,
-					struct device_attribute *attr,
-					char *page)
-{
-	return sysfs_emit(page, "%s\n", "ali_drw_pmu");
-}
-
 static umode_t ali_drw_pmu_identifier_attr_visible(struct kobject *kobj,
 						struct attribute *attr, int n)
 {
 	return attr->mode;
 }
 
-static struct device_attribute ali_drw_pmu_identifier_attr =
+static DEVICE_STRING_ATTR_RO(ali_drw_pmu_identifier, 0444, "ali_drw_pmu");
-	__ATTR(identifier, 0444, ali_drw_pmu_identifier_show, NULL);
 
 static struct attribute *ali_drw_pmu_identifier_attrs[] = {
-	&ali_drw_pmu_identifier_attr.attr,
+	&dev_attr_ali_drw_pmu_identifier.attr.attr,
 	NULL
 };
 

drivers/perf/arm-cci.c

@@ -127,8 +127,6 @@ enum cci_models {
 
 static void pmu_write_counters(struct cci_pmu *cci_pmu,
 				 unsigned long *mask);
-static ssize_t __maybe_unused cci_pmu_format_show(struct device *dev,
-			struct device_attribute *attr, char *buf);
 static ssize_t __maybe_unused cci_pmu_event_show(struct device *dev,
 			struct device_attribute *attr, char *buf);
 
@@ -138,7 +136,7 @@ static ssize_t __maybe_unused cci_pmu_event_show(struct device *dev,
 	})[0].attr.attr
 
 #define CCI_FORMAT_EXT_ATTR_ENTRY(_name, _config) \
-	CCI_EXT_ATTR_ENTRY(_name, cci_pmu_format_show, (char *)_config)
+	CCI_EXT_ATTR_ENTRY(_name, device_show_string, _config)
 #define CCI_EVENT_EXT_ATTR_ENTRY(_name, _config) \
 	CCI_EXT_ATTR_ENTRY(_name, cci_pmu_event_show, (unsigned long)_config)
 
@@ -688,14 +686,6 @@ static void __cci_pmu_disable(struct cci_pmu *cci_pmu)
 	writel(val, cci_pmu->ctrl_base + CCI_PMCR);
 }
 
-static ssize_t cci_pmu_format_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr = container_of(attr,
-				struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t cci_pmu_event_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {

drivers/perf/arm-ccn.c

@@ -215,18 +215,9 @@ static void arm_ccn_pmu_config_set(u64 *config, u32 node_xp, u32 type, u32 port)
 	*config |= (node_xp << 0) | (type << 8) | (port << 24);
 }
 
-static ssize_t arm_ccn_pmu_format_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *ea = container_of(attr,
-			struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)ea->var);
-}
-
 #define CCN_FORMAT_ATTR(_name, _config) \
 	struct dev_ext_attribute arm_ccn_pmu_format_attr_##_name = \
-			{ __ATTR(_name, S_IRUGO, arm_ccn_pmu_format_show, \
+			{ __ATTR(_name, S_IRUGO, device_show_string, \
 			NULL), _config }
 
 static CCN_FORMAT_ATTR(node, "config:0-7");

drivers/perf/arm_cspmu/arm_cspmu.c

@@ -223,16 +223,6 @@ arm_cspmu_event_attr_is_visible(struct kobject *kobj,
 	return attr->mode;
 }
 
-ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
-				struct device_attribute *attr,
-				char *buf)
-{
-	struct dev_ext_attribute *eattr =
-		container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_format_show);
-
 static struct attribute *arm_cspmu_format_attrs[] = {
 	ARM_CSPMU_FORMAT_EVENT_ATTR,
 	ARM_CSPMU_FORMAT_FILTER_ATTR,

drivers/perf/arm_cspmu/arm_cspmu.h

@@ -28,7 +28,7 @@
 	})[0].attr.attr)
 
 #define ARM_CSPMU_FORMAT_ATTR(_name, _config)				\
-	ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_sysfs_format_show, (char *)_config)
+	ARM_CSPMU_EXT_ATTR(_name, device_show_string, _config)
 
 #define ARM_CSPMU_EVENT_ATTR(_name, _config)				\
 	PMU_EVENT_ATTR_ID(_name, arm_cspmu_sysfs_event_show, _config)
@@ -167,11 +167,6 @@ ssize_t arm_cspmu_sysfs_event_show(struct device *dev,
 				   struct device_attribute *attr,
 				   char *buf);
 
-/* Default function to show format attribute in sysfs. */
-ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
-				    struct device_attribute *attr,
-				    char *buf);
-
 /* Register vendor backend. */
 int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match);
 

drivers/perf/arm_dsu_pmu.c

@@ -85,7 +85,7 @@
 	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_event_show, (unsigned long)_config)
 
 #define DSU_FORMAT_ATTR(_name, _config)		\
-	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_format_show, (char *)_config)
+	DSU_EXT_ATTR(_name, device_show_string, _config)
 
 #define DSU_CPUMASK_ATTR(_name, _config)	\
 	DSU_EXT_ATTR(_name, dsu_pmu_cpumask_show, (unsigned long)_config)
@@ -139,15 +139,6 @@ static ssize_t dsu_pmu_sysfs_event_show(struct device *dev,
 	return sysfs_emit(buf, "event=0x%lx\n", (unsigned long)eattr->var);
 }
 
-static ssize_t dsu_pmu_sysfs_format_show(struct device *dev,
-					 struct device_attribute *attr,
-					 char *buf)
-{
-	struct dev_ext_attribute *eattr = container_of(attr,
-					struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t dsu_pmu_cpumask_show(struct device *dev,
 				    struct device_attribute *attr,
 				    char *buf)

drivers/perf/cxl_pmu.c

@@ -208,21 +208,10 @@ static int cxl_pmu_parse_caps(struct device *dev, struct cxl_pmu_info *info)
 	return 0;
 }
 
-static ssize_t cxl_pmu_format_sysfs_show(struct device *dev,
-					 struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 #define CXL_PMU_FORMAT_ATTR(_name, _format)\
 	(&((struct dev_ext_attribute[]) {					\
 		{								\
-			.attr = __ATTR(_name, 0444,				\
+			.attr = __ATTR(_name, 0444, device_show_string, NULL),	\
-				       cxl_pmu_format_sysfs_show, NULL),	\
 			.var = (void *)_format					\
 		}								\
 		})[0].attr.attr)

drivers/perf/hisilicon/hisi_pcie_pmu.c

@@ -99,16 +99,6 @@ HISI_PCIE_PMU_FILTER_ATTR(len_mode, config1, 11, 10);
 HISI_PCIE_PMU_FILTER_ATTR(port, config2, 15, 0);
 HISI_PCIE_PMU_FILTER_ATTR(bdf, config2, 31, 16);
 
-static ssize_t hisi_pcie_format_sysfs_show(struct device *dev, struct device_attribute *attr,
-					   char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t hisi_pcie_event_sysfs_show(struct device *dev, struct device_attribute *attr,
 					  char *buf)
 {
@@ -120,8 +110,7 @@ static ssize_t hisi_pcie_event_sysfs_show(struct device *dev, struct device_attr
 
 #define HISI_PCIE_PMU_FORMAT_ATTR(_name, _format)                              \
 	(&((struct dev_ext_attribute[]){                                       \
-		{ .attr = __ATTR(_name, 0444, hisi_pcie_format_sysfs_show,     \
+		{ .attr = __ATTR(_name, 0444, device_show_string, NULL),       \
-				 NULL),                                        \
 		  .var = (void *)_format }                                     \
 	})[0].attr.attr)
 

drivers/perf/hisilicon/hisi_uncore_pmu.c

@@ -22,20 +22,6 @@
 
 #define HISI_MAX_PERIOD(nr) (GENMASK_ULL((nr) - 1, 0))
 
-/*
- * PMU format attributes
- */
-ssize_t hisi_format_sysfs_show(struct device *dev,
-			       struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-EXPORT_SYMBOL_GPL(hisi_format_sysfs_show);
-
 /*
  * PMU event attributes
  */

drivers/perf/hisilicon/hisi_uncore_pmu.h

@@ -33,7 +33,7 @@
 	})[0].attr.attr)
 
 #define HISI_PMU_FORMAT_ATTR(_name, _config)		\
-	HISI_PMU_ATTR(_name, hisi_format_sysfs_show, (void *)_config)
+	HISI_PMU_ATTR(_name, device_show_string, _config)
 #define HISI_PMU_EVENT_ATTR(_name, _config)		\
 	HISI_PMU_ATTR(_name, hisi_event_sysfs_show, (unsigned long)_config)
 
@@ -122,8 +122,6 @@ void hisi_uncore_pmu_enable(struct pmu *pmu);
 void hisi_uncore_pmu_disable(struct pmu *pmu);
 ssize_t hisi_event_sysfs_show(struct device *dev,
 			      struct device_attribute *attr, char *buf);
-ssize_t hisi_format_sysfs_show(struct device *dev,
-			       struct device_attribute *attr, char *buf);
 ssize_t hisi_cpumask_sysfs_show(struct device *dev,
 				struct device_attribute *attr, char *buf);
 int hisi_uncore_pmu_online_cpu(unsigned int cpu, struct hlist_node *node);

drivers/perf/hisilicon/hns3_pmu.c

@@ -363,16 +363,6 @@ HNS3_PMU_FILTER_ATTR(global, config1, 52, 52);
 	HNS3_PMU_EVT_PPS_##_name##_TIME,				\
 	HNS3_PMU_FILTER_INTR_##_name})
 
-static ssize_t hns3_pmu_format_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t hns3_pmu_event_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
@@ -421,7 +411,7 @@ static ssize_t hns3_pmu_filter_mode_show(struct device *dev,
 	})[0].attr.attr)
 
 #define HNS3_PMU_FORMAT_ATTR(_name, _format) \
-	HNS3_PMU_ATTR(_name, hns3_pmu_format_show, (void *)_format)
+	HNS3_PMU_ATTR(_name, device_show_string, _format)
 #define HNS3_PMU_EVENT_ATTR(_name, _event) \
 	HNS3_PMU_ATTR(_name, hns3_pmu_event_show, (void *)_event)
 #define HNS3_PMU_FLT_MODE_ATTR(_name, _event) \

drivers/perf/qcom_l3_pmu.c

@@ -609,18 +609,9 @@ static void qcom_l3_cache__event_read(struct perf_event *event)
 
 /* formats */
 
-static ssize_t l3cache_pmu_format_show(struct device *dev,
-				       struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *) eattr->var);
-}
-
 #define L3CACHE_PMU_FORMAT_ATTR(_name, _config)				      \
 	(&((struct dev_ext_attribute[]) {				      \
-		{ .attr = __ATTR(_name, 0444, l3cache_pmu_format_show, NULL), \
+		{ .attr = __ATTR(_name, 0444, device_show_string, NULL),      \
 		  .var = (void *) _config, }				      \
 	})[0].attr.attr)
 

drivers/perf/xgene_pmu.c

@@ -162,18 +162,9 @@ enum xgene_pmu_dev_type {
 /*
  * sysfs format attributes
  */
-static ssize_t xgene_pmu_format_show(struct device *dev,
-				     struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *) eattr->var);
-}
-
 #define XGENE_PMU_FORMAT_ATTR(_name, _config)		\
 	(&((struct dev_ext_attribute[]) {		\
-		{ .attr = __ATTR(_name, S_IRUGO, xgene_pmu_format_show, NULL), \
+		{ .attr = __ATTR(_name, S_IRUGO, device_show_string, NULL), \
 		  .var = (void *) _config, }		\
 	})[0].attr.attr)
 

drivers/platform/x86/asus-wmi.c

@@ -925,17 +925,12 @@ static ssize_t kbd_rgb_mode_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(kbd_rgb_mode);
 
-static ssize_t kbd_rgb_mode_index_show(struct device *device,
+static DEVICE_STRING_ATTR_RO(kbd_rgb_mode_index, 0444,
-						 struct device_attribute *attr,
+			     "cmd mode red green blue speed");
-						 char *buf)
-{
-	return sysfs_emit(buf, "%s\n", "cmd mode red green blue speed");
-}
-static DEVICE_ATTR_RO(kbd_rgb_mode_index);
 
 static struct attribute *kbd_rgb_mode_attrs[] = {
 	&dev_attr_kbd_rgb_mode.attr,
-	&dev_attr_kbd_rgb_mode_index.attr,
+	&dev_attr_kbd_rgb_mode_index.attr.attr,
 	NULL,
 };
 
@@ -977,17 +972,12 @@ static ssize_t kbd_rgb_state_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(kbd_rgb_state);
 
-static ssize_t kbd_rgb_state_index_show(struct device *device,
+static DEVICE_STRING_ATTR_RO(kbd_rgb_state_index, 0444,
-						 struct device_attribute *attr,
+			     "cmd boot awake sleep keyboard");
-						 char *buf)
-{
-	return sysfs_emit(buf, "%s\n", "cmd boot awake sleep keyboard");
-}
-static DEVICE_ATTR_RO(kbd_rgb_state_index);
 
 static struct attribute *kbd_rgb_state_attrs[] = {
 	&dev_attr_kbd_rgb_state.attr,
-	&dev_attr_kbd_rgb_state_index.attr,
+	&dev_attr_kbd_rgb_state_index.attr.attr,
 	NULL,
 };
 
@@ -2718,13 +2708,6 @@ static ssize_t pwm1_enable_store(struct device *dev,
 	return count;
 }
 
-static ssize_t fan1_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_FAN_DESC);
-}
-
 static ssize_t asus_hwmon_temp1(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -2759,13 +2742,6 @@ static ssize_t fan2_input_show(struct device *dev,
 	return sysfs_emit(buf, "%d\n", value * 100);
 }
 
-static ssize_t fan2_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_GPU_FAN_DESC);
-}
-
 /* Middle/Center fan on modern ROG laptops */
 static ssize_t fan3_input_show(struct device *dev,
 					struct device_attribute *attr,
@@ -2784,13 +2760,6 @@ static ssize_t fan3_input_show(struct device *dev,
 	return sysfs_emit(buf, "%d\n", value * 100);
 }
 
-static ssize_t fan3_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_MID_FAN_DESC);
-}
-
 static ssize_t pwm2_enable_show(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -2887,15 +2856,16 @@ static ssize_t pwm3_enable_store(struct device *dev,
 static DEVICE_ATTR_RW(pwm1);
 static DEVICE_ATTR_RW(pwm1_enable);
 static DEVICE_ATTR_RO(fan1_input);
-static DEVICE_ATTR_RO(fan1_label);
+static DEVICE_STRING_ATTR_RO(fan1_label, 0444, ASUS_FAN_DESC);
+
 /* Fan2 - GPU fan */
 static DEVICE_ATTR_RW(pwm2_enable);
 static DEVICE_ATTR_RO(fan2_input);
-static DEVICE_ATTR_RO(fan2_label);
+static DEVICE_STRING_ATTR_RO(fan2_label, 0444, ASUS_GPU_FAN_DESC);
 /* Fan3 - Middle/center fan */
 static DEVICE_ATTR_RW(pwm3_enable);
 static DEVICE_ATTR_RO(fan3_input);
-static DEVICE_ATTR_RO(fan3_label);
+static DEVICE_STRING_ATTR_RO(fan3_label, 0444, ASUS_MID_FAN_DESC);
 
 /* Temperature */
 static DEVICE_ATTR(temp1_input, S_IRUGO, asus_hwmon_temp1, NULL);
@@ -2906,11 +2876,11 @@ static struct attribute *hwmon_attributes[] = {
 	&dev_attr_pwm2_enable.attr,
 	&dev_attr_pwm3_enable.attr,
 	&dev_attr_fan1_input.attr,
-	&dev_attr_fan1_label.attr,
+	&dev_attr_fan1_label.attr.attr,
 	&dev_attr_fan2_input.attr,
-	&dev_attr_fan2_label.attr,
+	&dev_attr_fan2_label.attr.attr,
 	&dev_attr_fan3_input.attr,
-	&dev_attr_fan3_label.attr,
+	&dev_attr_fan3_label.attr.attr,
 
 	&dev_attr_temp1_input.attr,
 	NULL
@@ -2927,17 +2897,17 @@ static umode_t asus_hwmon_sysfs_is_visible(struct kobject *kobj,
 		if (asus->fan_type != FAN_TYPE_AGFN)
 			return 0;
 	} else if (attr == &dev_attr_fan1_input.attr
-	    || attr == &dev_attr_fan1_label.attr
+	    || attr == &dev_attr_fan1_label.attr.attr
 	    || attr == &dev_attr_pwm1_enable.attr) {
 		if (asus->fan_type == FAN_TYPE_NONE)
 			return 0;
 	} else if (attr == &dev_attr_fan2_input.attr
-	    || attr == &dev_attr_fan2_label.attr
+	    || attr == &dev_attr_fan2_label.attr.attr
 	    || attr == &dev_attr_pwm2_enable.attr) {
 		if (asus->gpu_fan_type == FAN_TYPE_NONE)
 			return 0;
 	} else if (attr == &dev_attr_fan3_input.attr
-	    || attr == &dev_attr_fan3_label.attr
+	    || attr == &dev_attr_fan3_label.attr.attr
 	    || attr == &dev_attr_pwm3_enable.attr) {
 		if (asus->mid_fan_type == FAN_TYPE_NONE)
 			return 0;

drivers/platform/x86/thinkpad_acpi.c

@@ -10828,13 +10828,7 @@ static struct ibm_struct auxmac_data = {
 	.name = "auxmac",
 };
 
-static ssize_t auxmac_show(struct device *dev,
+static DEVICE_STRING_ATTR_RO(auxmac, 0444, auxmac);
-			   struct device_attribute *attr,
-			   char *buf)
-{
-	return sysfs_emit(buf, "%s\n", auxmac);
-}
-static DEVICE_ATTR_RO(auxmac);
 
 static umode_t auxmac_attr_is_visible(struct kobject *kobj,
 				      struct attribute *attr, int n)
@@ -10843,7 +10837,7 @@ static umode_t auxmac_attr_is_visible(struct kobject *kobj,
 }
 
 static struct attribute *auxmac_attributes[] = {
-	&dev_attr_auxmac.attr,
+	&dev_attr_auxmac.attr.attr,
 	NULL
 };
 

drivers/platform/x86/toshiba_acpi.c

@@ -1821,12 +1821,7 @@ static DECLARE_WORK(kbd_bl_work, toshiba_acpi_kbd_bl_work);
 /*
  * Sysfs files
  */
-static ssize_t version_show(struct device *dev,
+static DEVICE_STRING_ATTR_RO(version, 0444, TOSHIBA_ACPI_VERSION);
-			    struct device_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", TOSHIBA_ACPI_VERSION);
-}
-static DEVICE_ATTR_RO(version);
 
 static ssize_t fan_store(struct device *dev,
 			 struct device_attribute *attr,
@@ -2435,7 +2430,7 @@ static ssize_t cooling_method_store(struct device *dev,
 static DEVICE_ATTR_RW(cooling_method);
 
 static struct attribute *toshiba_attributes[] = {
-	&dev_attr_version.attr,
+	&dev_attr_version.attr.attr,
 	&dev_attr_fan.attr,
 	&dev_attr_kbd_backlight_mode.attr,
 	&dev_attr_kbd_type.attr,

drivers/scsi/bfa/bfad_attr.c

@@ -853,13 +853,6 @@ bfad_im_hw_version_show(struct device *dev, struct device_attribute *attr,
 	return sysfs_emit(buf, "%s\n", hw_ver);
 }
 
-static ssize_t
-bfad_im_drv_version_show(struct device *dev, struct device_attribute *attr,
-				char *buf)
-{
-	return sysfs_emit(buf, "%s\n", BFAD_DRIVER_VERSION);
-}
-
 static ssize_t
 bfad_im_optionrom_version_show(struct device *dev,
 			 struct device_attribute *attr, char *buf)
@@ -901,13 +894,6 @@ bfad_im_num_of_ports_show(struct device *dev, struct device_attribute *attr,
 			bfa_get_nports(&bfad->bfa));
 }
 
-static ssize_t
-bfad_im_drv_name_show(struct device *dev, struct device_attribute *attr,
-				char *buf)
-{
-	return sysfs_emit(buf, "%s\n", BFAD_DRIVER_NAME);
-}
-
 static ssize_t
 bfad_im_num_of_discovered_ports_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
@@ -944,15 +930,15 @@ static          DEVICE_ATTR(symbolic_name, S_IRUGO,
 				bfad_im_symbolic_name_show, NULL);
 static          DEVICE_ATTR(hardware_version, S_IRUGO,
 				bfad_im_hw_version_show, NULL);
-static          DEVICE_ATTR(driver_version, S_IRUGO,
+static		DEVICE_STRING_ATTR_RO(driver_version, S_IRUGO,
-				bfad_im_drv_version_show, NULL);
+				BFAD_DRIVER_VERSION);
 static          DEVICE_ATTR(option_rom_version, S_IRUGO,
 				bfad_im_optionrom_version_show, NULL);
 static          DEVICE_ATTR(firmware_version, S_IRUGO,
 				bfad_im_fw_version_show, NULL);
 static          DEVICE_ATTR(number_of_ports, S_IRUGO,
 				bfad_im_num_of_ports_show, NULL);
-static          DEVICE_ATTR(driver_name, S_IRUGO, bfad_im_drv_name_show, NULL);
+static		DEVICE_STRING_ATTR_RO(driver_name, S_IRUGO, BFAD_DRIVER_NAME);
 static          DEVICE_ATTR(number_of_discovered_ports, S_IRUGO,
 				bfad_im_num_of_discovered_ports_show, NULL);
 
@@ -963,11 +949,11 @@ static struct attribute *bfad_im_host_attrs[] = {
 	&dev_attr_node_name.attr,
 	&dev_attr_symbolic_name.attr,
 	&dev_attr_hardware_version.attr,
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_option_rom_version.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_number_of_ports.attr,
-	&dev_attr_driver_name.attr,
+	&dev_attr_driver_name.attr.attr,
 	&dev_attr_number_of_discovered_ports.attr,
 	NULL,
 };
@@ -988,11 +974,11 @@ static struct attribute *bfad_im_vport_attrs[] = {
 	&dev_attr_node_name.attr,
 	&dev_attr_symbolic_name.attr,
 	&dev_attr_hardware_version.attr,
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_option_rom_version.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_number_of_ports.attr,
-	&dev_attr_driver_name.attr,
+	&dev_attr_driver_name.attr.attr,
 	&dev_attr_number_of_discovered_ports.attr,
 	NULL,
 };

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c

@@ -3613,12 +3613,6 @@ static void ibmvscsis_remove(struct vio_dev *vdev)
 	kfree(vscsi);
 }
 
-static ssize_t system_id_show(struct device *dev,
-			      struct device_attribute *attr, char *buf)
-{
-	return sysfs_emit(buf, "%s\n", system_id);
-}
-
 static ssize_t partition_number_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
@@ -3982,8 +3976,7 @@ static const struct target_core_fabric_ops ibmvscsis_ops = {
 
 static void ibmvscsis_dev_release(struct device *dev) {};
 
-static struct device_attribute dev_attr_system_id =
+static DEVICE_STRING_ATTR_RO(system_id, S_IRUGO, system_id);
-	__ATTR(system_id, S_IRUGO, system_id_show, NULL);
 
 static struct device_attribute dev_attr_partition_number =
 	__ATTR(partition_number, S_IRUGO, partition_number_show, NULL);
@@ -3992,7 +3985,7 @@ static struct device_attribute dev_attr_unit_address =
 	__ATTR(unit_address, S_IRUGO, unit_address_show, NULL);
 
 static struct attribute *ibmvscsis_dev_attrs[] = {
-	&dev_attr_system_id.attr,
+	&dev_attr_system_id.attr.attr,
 	&dev_attr_partition_number.attr,
 	&dev_attr_unit_address.attr,
 };

drivers/scsi/mvsas/mv_init.c

@@ -676,13 +676,7 @@ static struct pci_driver mvs_pci_driver = {
 	.remove		= mvs_pci_remove,
 };
 
-static ssize_t driver_version_show(struct device *cdev,
+static DEVICE_STRING_ATTR_RO(driver_version, 0444, DRV_VERSION);
-				   struct device_attribute *attr, char *buffer)
-{
-	return sysfs_emit(buffer, "%s\n", DRV_VERSION);
-}
-
-static DEVICE_ATTR_RO(driver_version);
 
 static ssize_t interrupt_coalescing_store(struct device *cdev,
 					  struct device_attribute *attr,
@@ -757,7 +751,7 @@ static void __exit mvs_exit(void)
 }
 
 static struct attribute *mvst_host_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_interrupt_coalescing.attr,
 	NULL,
 };

drivers/scsi/qla2xxx/qla_attr.c

@@ -1067,13 +1067,6 @@ qla2x00_free_sysfs_attr(scsi_qla_host_t *vha, bool stop_beacon)
 
 /* Scsi_Host attributes. */
 
-static ssize_t
-qla2x00_driver_version_show(struct device *dev,
-			  struct device_attribute *attr, char *buf)
-{
-	return scnprintf(buf, PAGE_SIZE, "%s\n", qla2x00_version_str);
-}
-
 static ssize_t
 qla2x00_fw_version_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
@@ -2412,7 +2405,7 @@ qla2x00_dport_diagnostics_show(struct device *dev,
 static DEVICE_ATTR(dport_diagnostics, 0444,
 	   qla2x00_dport_diagnostics_show, NULL);
 
-static DEVICE_ATTR(driver_version, S_IRUGO, qla2x00_driver_version_show, NULL);
+static DEVICE_STRING_ATTR_RO(driver_version, S_IRUGO, qla2x00_version_str);
 static DEVICE_ATTR(fw_version, S_IRUGO, qla2x00_fw_version_show, NULL);
 static DEVICE_ATTR(serial_num, S_IRUGO, qla2x00_serial_num_show, NULL);
 static DEVICE_ATTR(isp_name, S_IRUGO, qla2x00_isp_name_show, NULL);
@@ -2478,7 +2471,7 @@ static DEVICE_ATTR(port_no, 0444, qla2x00_port_no_show, NULL);
 static DEVICE_ATTR(fw_attr, 0444, qla2x00_fw_attr_show, NULL);
 
 static struct attribute *qla2x00_host_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_fw_version.attr,
 	&dev_attr_serial_num.attr,
 	&dev_attr_isp_name.attr,

drivers/scsi/smartpqi/smartpqi_init.c

@@ -6891,12 +6891,6 @@ static ssize_t pqi_firmware_version_show(struct device *dev,
 	return scnprintf(buffer, PAGE_SIZE, "%s\n", ctrl_info->firmware_version);
 }
 
-static ssize_t pqi_driver_version_show(struct device *dev,
-	struct device_attribute *attr, char *buffer)
-{
-	return scnprintf(buffer, PAGE_SIZE, "%s\n", DRIVER_VERSION BUILD_TIMESTAMP);
-}
-
 static ssize_t pqi_serial_number_show(struct device *dev,
 	struct device_attribute *attr, char *buffer)
 {
@@ -7065,7 +7059,8 @@ static ssize_t pqi_host_enable_r6_writes_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR(driver_version, 0444, pqi_driver_version_show, NULL);
+static DEVICE_STRING_ATTR_RO(driver_version, 0444,
+	DRIVER_VERSION BUILD_TIMESTAMP);
 static DEVICE_ATTR(firmware_version, 0444, pqi_firmware_version_show, NULL);
 static DEVICE_ATTR(model, 0444, pqi_model_show, NULL);
 static DEVICE_ATTR(serial_number, 0444, pqi_serial_number_show, NULL);
@@ -7082,7 +7077,7 @@ static DEVICE_ATTR(enable_r6_writes, 0644,
 	pqi_host_enable_r6_writes_show, pqi_host_enable_r6_writes_store);
 
 static struct attribute *pqi_shost_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_model.attr,
 	&dev_attr_serial_number.attr,

drivers/thermal/intel/int340x_thermal/int3400_thermal.c

@@ -73,14 +73,7 @@ struct odvp_attr {
 	struct device_attribute attr;
 };
 
-static ssize_t data_vault_read(struct file *file, struct kobject *kobj,
+static BIN_ATTR_SIMPLE_RO(data_vault);
-	     struct bin_attribute *attr, char *buf, loff_t off, size_t count)
-{
-	memcpy(buf, attr->private + off, count);
-	return count;
-}
-
-static BIN_ATTR_RO(data_vault, 0);
 
 static struct bin_attribute *data_attributes[] = {
 	&bin_attr_data_vault,

fs/kernfs/mount.c

@@ -206,7 +206,7 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
 				  struct super_block *sb)
 {
 	struct dentry *dentry;
-	struct kernfs_node *knparent = NULL;
+	struct kernfs_node *knparent;
 
 	BUG_ON(sb->s_op != &kernfs_sops);
 

fs/sysfs/file.c

@@ -785,3 +785,30 @@ int sysfs_emit_at(char *buf, int at, const char *fmt, ...)
 	return len;
 }
 EXPORT_SYMBOL_GPL(sysfs_emit_at);
+
+/**
+ *	sysfs_bin_attr_simple_read - read callback to simply copy from memory.
+ *	@file:	attribute file which is being read.
+ *	@kobj:	object to which the attribute belongs.
+ *	@attr:	attribute descriptor.
+ *	@buf:	destination buffer.
+ *	@off:	offset in bytes from which to read.
+ *	@count:	maximum number of bytes to read.
+ *
+ * Simple ->read() callback for bin_attributes backed by a buffer in memory.
+ * The @private and @size members in struct bin_attribute must be set to the
+ * buffer's location and size before the bin_attribute is created in sysfs.
+ *
+ * Bounds check for @off and @count is done in sysfs_kf_bin_read().
+ * Negative value check for @off is done in vfs_setpos() and default_llseek().
+ *
+ * Returns number of bytes written to @buf.
+ */
+ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj,
+				   struct bin_attribute *attr, char *buf,
+				   loff_t off, size_t count)
+{
+	memcpy(buf, attr->private + off, count);
+	return count;
+}
+EXPORT_SYMBOL_GPL(sysfs_bin_attr_simple_read);

include/linux/device.h

@@ -132,6 +132,8 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 			char *buf);
 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count);
+ssize_t device_show_string(struct device *dev, struct device_attribute *attr,
+			   char *buf);
 
 /**
  * DEVICE_ATTR - Define a device attribute.
@@ -251,6 +253,19 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 	struct dev_ext_attribute dev_attr_##_name = \
 		{ __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) }
 
+/**
+ * DEVICE_STRING_ATTR_RO - Define a device attribute backed by a r/o string.
+ * @_name: Attribute name.
+ * @_mode: File mode.
+ * @_var: Identifier of string.
+ *
+ * Like DEVICE_ULONG_ATTR(), but @_var is a string. Because the length of the
+ * string allocation is unknown, the attribute must be read-only.
+ */
+#define DEVICE_STRING_ATTR_RO(_name, _mode, _var) \
+	struct dev_ext_attribute dev_attr_##_name = \
+		{ __ATTR(_name, (_mode) & ~0222, device_show_string, NULL), (_var) }
+
 #define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
 	struct device_attribute dev_attr_##_name =		\
 		__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
@@ -1210,17 +1225,6 @@ int __must_check devm_device_add_groups(struct device *dev,
 int __must_check devm_device_add_group(struct device *dev,
 				       const struct attribute_group *grp);
 
-/*
- * Platform "fixup" functions - allow the platform to have their say
- * about devices and actions that the general device layer doesn't
- * know about.
- */
-/* Notify platform of device discovery */
-extern int (*platform_notify)(struct device *dev);
-
-extern int (*platform_notify_remove)(struct device *dev);
-
-
 /*
  * get_device - atomically increment the reference count for the device.
  *

include/linux/sysfs.h

@@ -371,6 +371,17 @@ struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RO(_name, _size)
 #define BIN_ATTR_ADMIN_RW(_name, _size)					\
 struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RW(_name, _size)
 
+#define __BIN_ATTR_SIMPLE_RO(_name, _mode) {				\
+	.attr	= { .name = __stringify(_name), .mode = _mode },	\
+	.read	= sysfs_bin_attr_simple_read,				\
+}
+
+#define BIN_ATTR_SIMPLE_RO(_name)					\
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_SIMPLE_RO(_name, 0444)
+
+#define BIN_ATTR_SIMPLE_ADMIN_RO(_name)					\
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_SIMPLE_RO(_name, 0400)
+
 struct sysfs_ops {
 	ssize_t	(*show)(struct kobject *, struct attribute *, char *);
 	ssize_t	(*store)(struct kobject *, struct attribute *, const char *, size_t);
@@ -478,6 +489,10 @@ int sysfs_emit(char *buf, const char *fmt, ...);
 __printf(3, 4)
 int sysfs_emit_at(char *buf, int at, const char *fmt, ...);
 
+ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj,
+				   struct bin_attribute *attr, char *buf,
+				   loff_t off, size_t count);
+
 #else /* CONFIG_SYSFS */
 
 static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)

init/initramfs.c

@@ -575,15 +575,7 @@ extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
 #include <linux/kexec.h>
 
-static ssize_t raw_read(struct file *file, struct kobject *kobj,
+static BIN_ATTR(initrd, 0440, sysfs_bin_attr_simple_read, NULL, 0);
-			struct bin_attribute *attr, char *buf,
-			loff_t pos, size_t count)
-{
-	memcpy(buf, attr->private + pos, count);
-	return count;
-}
-
-static BIN_ATTR(initrd, 0440, raw_read, NULL, 0);
 
 void __init reserve_initrd_mem(void)
 {

kernel/module/sysfs.c

@@ -146,17 +146,6 @@ struct module_notes_attrs {
 	struct bin_attribute attrs[] __counted_by(notes);
 };
 
-static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
-				 struct bin_attribute *bin_attr,
-				 char *buf, loff_t pos, size_t count)
-{
-	/*
-	 * The caller checked the pos and count against our size.
-	 */
-	memcpy(buf, bin_attr->private + pos, count);
-	return count;
-}
-
 static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
 			     unsigned int i)
 {
@@ -205,7 +194,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info)
 			nattr->attr.mode = 0444;
 			nattr->size = info->sechdrs[i].sh_size;
 			nattr->private = (void *)info->sechdrs[i].sh_addr;
-			nattr->read = module_notes_read;
+			nattr->read = sysfs_bin_attr_simple_read;
 			++nattr;
 		}
 		++loaded;