Merge tag 'driver-core-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here's the driver-core / kobject / lz4 tree update for 4.1-rc1.

  Everything here has been in linux-next for a while with no reported
  issues.  It's mostly just coding style cleanups, with other minor
  changes in here as well, nothing big"

* tag 'driver-core-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  debugfs: allow bad parent pointers to be passed in
  stable_kernel_rules: Add clause about specification of kernel versions to patch.
  kobject: WARN as tip when call kobject_get() to a kobject not initialized
  lib/lz4: Pull out constant tables
  drivers: platform: parse IRQ flags from resources
  driver core: Make probe deferral more quiet
  drivers/core/of: Add symlink to device-tree from devices with an OF node
  device: Add dev_of_node() accessor
  drivers: base: fw: fix ret value when loading fw
  firmware: Avoid manual device_create_file() calls
  drivers/base: cacheinfo: validate device node for all the caches
  drivers/base: use tabs where possible in code indentation
  driver core: add missing blank line after declaration
  drivers: base: node: Delete space after pointer declaration
  drivers: base: memory: Use tabs instead of spaces
  firmware_class: Fix whitespace and indentation
  drivers: base: dma-mapping: Erase blank space after pointer
  drivers: base: class: Add a blank line after declarations
  attribute_container: fix missing blank lines after declarations
  drivers: base: memory: Fix switch indent
  ...

Documentation/ABI/stable/sysfs-devices

+# Note: This documents additional properties of any device beyond what
+# is documented in Documentation/sysfs-rules.txt
+
+What:		/sys/devices/*/of_path
+Date:		February 2015
+Contact:	Device Tree mailing list <devicetree@vger.kernel.org>
+Description:
+		Any device associated with a device-tree node will have
+		an of_path symlink pointing to the corresponding device
+		node in /sys/firmware/devicetree/

Documentation/stable_kernel_rules.txt

@@ -81,6 +81,16 @@ format in the sign-off area:
      git cherry-pick fd21073
      git cherry-pick <this commit>
 
+Also, some patches may have kernel version prerequisites.  This can be
+specified in the following format in the sign-off area:
+
+     Cc:  <stable@vger.kernel.org> # 3.3.x-
+
+   The tag has the meaning of:
+     git cherry-pick <this commit>
+
+   For each "-stable" tree starting with the specified version.
+
 Following the submission:
 
  - The sender will receive an ACK when the patch has been accepted into the

drivers/base/attribute_container.c

@@ -94,6 +94,7 @@ int
 attribute_container_unregister(struct attribute_container *cont)
 {
 	int retval = -EBUSY;
+
 	mutex_lock(&attribute_container_mutex);
 	spin_lock(&cont->containers.k_lock);
 	if (!list_empty(&cont->containers.k_list))
@@ -349,6 +350,7 @@ int
 attribute_container_add_class_device(struct device *classdev)
 {
 	int error = device_add(classdev);
+
 	if (error)
 		return error;
 	return attribute_container_add_attrs(classdev);

drivers/base/bus.c

@@ -515,11 +515,11 @@ int bus_add_device(struct device *dev)
 			goto out_put;
 		error = device_add_groups(dev, bus->dev_groups);
 		if (error)
-			goto out_groups;
+			goto out_id;
 		error = sysfs_create_link(&bus->p->devices_kset->kobj,
 						&dev->kobj, dev_name(dev));
 		if (error)
-			goto out_id;
+			goto out_groups;
 		error = sysfs_create_link(&dev->kobj,
 				&dev->bus->p->subsys.kobj, "subsystem");
 		if (error)

drivers/base/cacheinfo.c

@@ -62,15 +62,21 @@ static int cache_setup_of_node(unsigned int cpu)
 		return -ENOENT;
 	}
 
-	while (np && index < cache_leaves(cpu)) {
+	while (index < cache_leaves(cpu)) {
 		this_leaf = this_cpu_ci->info_list + index;
 		if (this_leaf->level != 1)
 			np = of_find_next_cache_node(np);
 		else
 			np = of_node_get(np);/* cpu node itself */
+		if (!np)
+			break;
 		this_leaf->of_node = np;
 		index++;
 	}
+
+	if (index != cache_leaves(cpu)) /* not all OF nodes populated */
+		return -ENOENT;
+
 	return 0;
 }
 
@@ -189,8 +195,11 @@ static int detect_cache_attributes(unsigned int cpu)
 	 * will be set up here only if they are not populated already
 	 */
 	ret = cache_shared_cpu_map_setup(cpu);
-	if (ret)
+	if (ret) {
+		pr_warn("Unable to detect cache hierarcy from DT for CPU %d\n",
+			cpu);
 		goto free_ci;
+	}
 	return 0;
 
 free_ci:

drivers/base/class.c

@@ -90,6 +90,7 @@ int class_create_file_ns(struct class *cls, const struct class_attribute *attr,
 			 const void *ns)
 {
 	int error;
+
 	if (cls)
 		error = sysfs_create_file_ns(&cls->p->subsys.kobj,
 					     &attr->attr, ns);
@@ -488,6 +489,7 @@ ssize_t show_class_attr_string(struct class *class,
 			       struct class_attribute *attr, char *buf)
 {
 	struct class_attribute_string *cs;
+
 	cs = container_of(attr, struct class_attribute_string, attr);
 	return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
 }

drivers/base/core.c

@@ -805,8 +805,16 @@ static void cleanup_device_parent(struct device *dev)
 
 static int device_add_class_symlinks(struct device *dev)
 {
+	struct device_node *of_node = dev_of_node(dev);
 	int error;
 
+	if (of_node) {
+		error = sysfs_create_link(&dev->kobj, &of_node->kobj,"of_node");
+		if (error)
+			dev_warn(dev, "Error %d creating of_node link\n",error);
+		/* An error here doesn't warrant bringing down the device */
+	}
+
 	if (!dev->class)
 		return 0;
 
@@ -814,7 +822,7 @@ static int device_add_class_symlinks(struct device *dev)
 				  &dev->class->p->subsys.kobj,
 				  "subsystem");
 	if (error)
-		goto out;
+		goto out_devnode;
 
 	if (dev->parent && device_is_not_partition(dev)) {
 		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
@@ -842,12 +850,16 @@ static int device_add_class_symlinks(struct device *dev)
 
 out_subsys:
 	sysfs_remove_link(&dev->kobj, "subsystem");
-out:
+out_devnode:
+	sysfs_remove_link(&dev->kobj, "of_node");
 	return error;
 }
 
 static void device_remove_class_symlinks(struct device *dev)
 {
+	if (dev_of_node(dev))
+		sysfs_remove_link(&dev->kobj, "of_node");
+
 	if (!dev->class)
 		return;
 
@@ -1095,7 +1107,6 @@ int device_add(struct device *dev)
 	kobject_del(&dev->kobj);
  Error:
 	cleanup_device_parent(dev);
-	if (parent)
 	put_device(parent);
 name_error:
 	kfree(dev->p);

drivers/base/dd.c

@@ -320,21 +320,25 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	dev->driver = NULL;
 	dev_set_drvdata(dev, NULL);
 
-	if (ret == -EPROBE_DEFER) {
+	switch (ret) {
+	case -EPROBE_DEFER:
 		/* Driver requested deferred probing */
-		dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
+		dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
 		driver_deferred_probe_add(dev);
 		/* Did a trigger occur while probing? Need to re-trigger if yes */
 		if (local_trigger_count != atomic_read(&deferred_trigger_count))
 			driver_deferred_probe_trigger();
-	} else if (ret != -ENODEV && ret != -ENXIO) {
+		break;
+	case -ENODEV:
+	case -ENXIO:
+		pr_debug("%s: probe of %s rejects match %d\n",
+			 drv->name, dev_name(dev), ret);
+		break;
+	default:
 		/* driver matched but the probe failed */
 		printk(KERN_WARNING
 		       "%s: probe of %s failed with error %d\n",
 		       drv->name, dev_name(dev), ret);
-	} else {
-		pr_debug("%s: probe of %s rejects match %d\n",
-		       drv->name, dev_name(dev), ret);
 	}
 	/*
 	 * Ignore errors returned by ->probe so that the next driver can try

drivers/base/dma-mapping.c

@@ -62,7 +62,7 @@ static int dmam_match(struct device *dev, void *res, void *match_data)
  * RETURNS:
  * Pointer to allocated memory on success, NULL on failure.
  */
-void * dmam_alloc_coherent(struct device *dev, size_t size,
+void *dmam_alloc_coherent(struct device *dev, size_t size,
 			   dma_addr_t *dma_handle, gfp_t gfp)
 {
 	struct dma_devres *dr;

drivers/base/driver.c

@@ -103,6 +103,7 @@ int driver_create_file(struct device_driver *drv,
 		       const struct driver_attribute *attr)
 {
 	int error;
+
 	if (drv)
 		error = sysfs_create_file(&drv->p->kobj, &attr->attr);
 	else

drivers/base/firmware_class.c

@@ -181,7 +181,7 @@ static struct firmware_buf *__allocate_fw_buf(const char *fw_name,
 {
 	struct firmware_buf *buf;
 
-	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1 , GFP_ATOMIC);
+	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1, GFP_ATOMIC);
 
 	if (!buf)
 		return buf;
@@ -835,6 +835,26 @@ static struct bin_attribute firmware_attr_data = {
 	.write = firmware_data_write,
 };
 
+static struct attribute *fw_dev_attrs[] = {
+	&dev_attr_loading.attr,
+	NULL
+};
+
+static struct bin_attribute *fw_dev_bin_attrs[] = {
+	&firmware_attr_data,
+	NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+	.attrs = fw_dev_attrs,
+	.bin_attrs = fw_dev_bin_attrs,
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+	&fw_dev_attr_group,
+	NULL
+};
+
 static struct firmware_priv *
 fw_create_instance(struct firmware *firmware, const char *fw_name,
 		   struct device *device, unsigned int opt_flags)
@@ -856,6 +876,7 @@ fw_create_instance(struct firmware *firmware, const char *fw_name,
 	dev_set_name(f_dev, "%s", fw_name);
 	f_dev->parent = device;
 	f_dev->class = &firmware_class;
+	f_dev->groups = fw_dev_attr_groups;
 exit:
 	return fw_priv;
 }
@@ -879,25 +900,10 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
 		goto err_put_dev;
 	}
 
-	retval = device_create_bin_file(f_dev, &firmware_attr_data);
-	if (retval) {
-		dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
-		goto err_del_dev;
-	}
-
 	mutex_lock(&fw_lock);
 	list_add(&buf->pending_list, &pending_fw_head);
 	mutex_unlock(&fw_lock);
 
-	retval = device_create_file(f_dev, &dev_attr_loading);
-	if (retval) {
-		mutex_lock(&fw_lock);
-		list_del_init(&buf->pending_list);
-		mutex_unlock(&fw_lock);
-		dev_err(f_dev, "%s: device_create_file failed\n", __func__);
-		goto err_del_bin_attr;
-	}
-
 	if (opt_flags & FW_OPT_UEVENT) {
 		buf->need_uevent = true;
 		dev_set_uevent_suppress(f_dev, false);
@@ -913,6 +919,8 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
 		mutex_lock(&fw_lock);
 		fw_load_abort(fw_priv);
 		mutex_unlock(&fw_lock);
+	} else if (retval > 0) {
+		retval = 0;
 	}
 
 	if (is_fw_load_aborted(buf))
@@ -920,10 +928,6 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
 	else if (!buf->data)
 		retval = -ENOMEM;
 
-	device_remove_file(f_dev, &dev_attr_loading);
-err_del_bin_attr:
-	device_remove_bin_file(f_dev, &firmware_attr_data);
-err_del_dev:
 	device_del(f_dev);
 err_put_dev:
 	put_device(f_dev);
@@ -1196,6 +1200,7 @@ int request_firmware_direct(const struct firmware **firmware_p,
 			    const char *name, struct device *device)
 {
 	int ret;
+
 	__module_get(THIS_MODULE);
 	ret = _request_firmware(firmware_p, name, device,
 				FW_OPT_UEVENT | FW_OPT_NO_WARN);
@@ -1276,7 +1281,7 @@ request_firmware_nowait(
 {
 	struct firmware_work *fw_work;
 
-	fw_work = kzalloc(sizeof (struct firmware_work), gfp);
+	fw_work = kzalloc(sizeof(struct firmware_work), gfp);
 	if (!fw_work)
 		return -ENOMEM;
 

drivers/base/map.c

@@ -41,8 +41,7 @@ int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
 	if (n > 255)
 		n = 255;
 
-	p = kmalloc(sizeof(struct probe) * n, GFP_KERNEL);
-
+	p = kmalloc_array(n, sizeof(struct probe), GFP_KERNEL);
 	if (p == NULL)
 		return -ENOMEM;
 

drivers/base/node.c

@@ -180,7 +180,7 @@ static ssize_t node_read_vmstat(struct device *dev,
 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 
 static ssize_t node_read_distance(struct device *dev,
-			struct device_attribute *attr, char * buf)
+			struct device_attribute *attr, char *buf)
 {
 	int nid = dev->id;
 	int len = 0;
@@ -200,6 +200,17 @@ static ssize_t node_read_distance(struct device *dev,
 }
 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 
+static struct attribute *node_dev_attrs[] = {
+	&dev_attr_cpumap.attr,
+	&dev_attr_cpulist.attr,
+	&dev_attr_meminfo.attr,
+	&dev_attr_numastat.attr,
+	&dev_attr_distance.attr,
+	&dev_attr_vmstat.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(node_dev);
+
 #ifdef CONFIG_HUGETLBFS
 /*
  * hugetlbfs per node attributes registration interface:
@@ -273,16 +284,10 @@ static int register_node(struct node *node, int num, struct node *parent)
 	node->dev.id = num;
 	node->dev.bus = &node_subsys;
 	node->dev.release = node_device_release;
+	node->dev.groups = node_dev_groups;
 	error = device_register(&node->dev);
 
 	if (!error){
-		device_create_file(&node->dev, &dev_attr_cpumap);
-		device_create_file(&node->dev, &dev_attr_cpulist);
-		device_create_file(&node->dev, &dev_attr_meminfo);
-		device_create_file(&node->dev, &dev_attr_numastat);
-		device_create_file(&node->dev, &dev_attr_distance);
-		device_create_file(&node->dev, &dev_attr_vmstat);
-
 		hugetlb_register_node(node);
 
 		compaction_register_node(node);
@@ -299,13 +304,6 @@ static int register_node(struct node *node, int num, struct node *parent)
  */
 void unregister_node(struct node *node)
 {
-	device_remove_file(&node->dev, &dev_attr_cpumap);
-	device_remove_file(&node->dev, &dev_attr_cpulist);
-	device_remove_file(&node->dev, &dev_attr_meminfo);
-	device_remove_file(&node->dev, &dev_attr_numastat);
-	device_remove_file(&node->dev, &dev_attr_distance);
-	device_remove_file(&node->dev, &dev_attr_vmstat);
-
 	hugetlb_unregister_node(node);		/* no-op, if memoryless node */
 
 	device_unregister(&node->dev);

drivers/base/platform.c

@@ -101,6 +101,15 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
 	}
 
 	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
+	/*
+	 * The resources may pass trigger flags to the irqs that need
+	 * to be set up. It so happens that the trigger flags for
+	 * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER*
+	 * settings.
+	 */
+	if (r && r->flags & IORESOURCE_BITS)
+		irqd_set_trigger_type(irq_get_irq_data(r->start),
+				      r->flags & IORESOURCE_BITS);
 
 	return r ? r->start : -ENXIO;
 #endif

drivers/base/property.c

@@ -365,7 +365,7 @@ int fwnode_property_read_string(struct fwnode_handle *fwnode,
 				const char *propname, const char **val)
 {
 	if (is_of_node(fwnode))
-		return of_property_read_string(of_node(fwnode),propname, val);
+		return of_property_read_string(of_node(fwnode), propname, val);
 	else if (is_acpi_node(fwnode))
 		return acpi_dev_prop_read(acpi_node(fwnode), propname,
 					  DEV_PROP_STRING, val, 1);

fs/debugfs/inode.c

@@ -254,6 +254,9 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
 
 	pr_debug("debugfs: creating file '%s'\n",name);
 
+	if (IS_ERR(parent))
+		return parent;
+
 	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
 			      &debugfs_mount_count);
 	if (error)

fs/sysfs/group.c

@@ -41,7 +41,7 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
 
 	if (grp->attrs) {
 		for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
-			umode_t mode = 0;
+			umode_t mode = (*attr)->mode;
 
 			/*
 			 * In update mode, we're changing the permissions or
@@ -55,9 +55,14 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
 				if (!mode)
 					continue;
 			}
+
+			WARN(mode & ~(SYSFS_PREALLOC | 0664),
+			     "Attribute %s: Invalid permissions 0%o\n",
+			     (*attr)->name, mode);
+
+			mode &= SYSFS_PREALLOC | 0664;
 			error = sysfs_add_file_mode_ns(parent, *attr, false,
-						       (*attr)->mode | mode,
-						       NULL);
+						       mode, NULL);
 			if (unlikely(error))
 				break;
 		}

include/linux/device.h

@@ -916,6 +916,13 @@ static inline void device_lock_assert(struct device *dev)
 	lockdep_assert_held(&dev->mutex);
 }
 
+static inline struct device_node *dev_of_node(struct device *dev)
+{
+	if (!IS_ENABLED(CONFIG_OF))
+		return NULL;
+	return dev->of_node;
+}
+
 void driver_init(void);
 
 /*

include/linux/sysfs.h

@@ -57,6 +57,21 @@ do {							\
 #define sysfs_attr_init(attr) do {} while (0)
 #endif
 
+/**
+ * struct attribute_group - data structure used to declare an attribute group.
+ * @name:	Optional: Attribute group name
+ *		If specified, the attribute group will be created in
+ *		a new subdirectory with this name.
+ * @is_visible:	Optional: Function to return permissions associated with an
+ *		attribute of the group. Will be called repeatedly for each
+ *		attribute in the group. Only read/write permissions as well as
+ *		SYSFS_PREALLOC are accepted. Must return 0 if an attribute is
+ *		not visible. The returned value will replace static permissions
+ *		defined in struct attribute or struct bin_attribute.
+ * @attrs:	Pointer to NULL terminated list of attributes.
+ * @bin_attrs:	Pointer to NULL terminated list of binary attributes.
+ *		Either attrs or bin_attrs or both must be provided.
+ */
 struct attribute_group {
 	const char		*name;
 	umode_t			(*is_visible)(struct kobject *,

lib/kobject.c

@@ -576,8 +576,13 @@ void kobject_del(struct kobject *kobj)
  */
 struct kobject *kobject_get(struct kobject *kobj)
 {
-	if (kobj)
+	if (kobj) {
+		if (!kobj->state_initialized)
+			WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
+			       "initialized, yet kobject_get() is being "
+			       "called.\n", kobject_name(kobj), kobj);
 		kref_get(&kobj->kref);
+	}
 	return kobj;
 }
 

lib/lz4/lz4_decompress.c

@@ -47,6 +47,11 @@
 
 #include "lz4defs.h"
 
+static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+#if LZ4_ARCH64
+static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
+#endif
+
 static int lz4_uncompress(const char *source, char *dest, int osize)
 {
 	const BYTE *ip = (const BYTE *) source;
@@ -56,10 +61,6 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
 	BYTE *cpy;
 	unsigned token;
 	size_t length;
-	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
-#if LZ4_ARCH64
-	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
-#endif
 
 	while (1) {
 
@@ -116,7 +117,7 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
 		/* copy repeated sequence */
 		if (unlikely((op - ref) < STEPSIZE)) {
 #if LZ4_ARCH64
-			size_t dec64 = dec64table[op - ref];
+			int dec64 = dec64table[op - ref];
 #else
 			const int dec64 = 0;
 #endif
@@ -177,11 +178,6 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 	BYTE * const oend = op + maxoutputsize;
 	BYTE *cpy;
 
-	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
-#if LZ4_ARCH64
-	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
-#endif
-
 	/* Main Loop */
 	while (ip < iend) {
 
@@ -249,7 +245,7 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 		/* copy repeated sequence */
 		if (unlikely((op - ref) < STEPSIZE)) {
 #if LZ4_ARCH64
-			size_t dec64 = dec64table[op - ref];
+			int dec64 = dec64table[op - ref];
 #else
 			const int dec64 = 0;
 #endif

samples/kobject/kobject-example.c

@@ -36,7 +36,12 @@ static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr,
 static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr,
 			 const char *buf, size_t count)
 {
-	sscanf(buf, "%du", &foo);
+	int ret;
+
+	ret = kstrtoint(buf, 10, &foo);
+	if (ret < 0)
+		return ret;
+
 	return count;
 }
 
@@ -63,9 +68,12 @@ static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr,
 static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,
 		       const char *buf, size_t count)
 {
-	int var;
+	int var, ret;
+
+	ret = kstrtoint(buf, 10, &var);
+	if (ret < 0)
+		return ret;
 
-	sscanf(buf, "%du", &var);
 	if (strcmp(attr->attr.name, "baz") == 0)
 		baz = var;
 	else
@@ -134,5 +142,5 @@ static void __exit example_exit(void)
 
 module_init(example_init);
 module_exit(example_exit);
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");

samples/kobject/kset-example.c

@@ -120,7 +120,12 @@ static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
 static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
 			 const char *buf, size_t count)
 {
-	sscanf(buf, "%du", &foo_obj->foo);
+	int ret;
+
+	ret = kstrtoint(buf, 10, &foo_obj->foo);
+	if (ret < 0)
+		return ret;
+
 	return count;
 }
 
@@ -147,9 +152,12 @@ static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
 static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
 		       const char *buf, size_t count)
 {
-	int var;
+	int var, ret;
+
+	ret = kstrtoint(buf, 10, &var);
+	if (ret < 0)
+		return ret;
 
-	sscanf(buf, "%du", &var);
 	if (strcmp(attr->attr.name, "baz") == 0)
 		foo_obj->baz = var;
 	else
@@ -277,5 +285,5 @@ static void __exit example_exit(void)
 
 module_init(example_init);
 module_exit(example_exit);
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");