Driver core: change add_uevent_var to use a struct

This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.

Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

34 files changed, 175 insertions, 415 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 64620d668742..5b4d462117cf 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -319,16 +319,18 @@ static int acpi_bus_match(struct device *dev, struct device_driver *drv)
 	return !acpi_match_device_ids(acpi_dev, acpi_drv->ids);
 }
 
-static int acpi_device_uevent(struct device *dev, char **envp, int num_envp,
-			      char *buffer, int buffer_size)
+static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct acpi_device *acpi_dev = to_acpi_device(dev);
+	int len;
 
-	strcpy(buffer, "MODALIAS=");
-	if (create_modalias(acpi_dev, buffer + 9, buffer_size - 9) > 0) {
-		envp[0] = buffer;
-		envp[1] = NULL;
-	}
+	if (add_uevent_var(env, "MODALIAS="))
+		return -ENOMEM;
+	len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
+			      sizeof(env->buf) - env->buflen);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+	env->buflen += len;
 	return 0;
 }
 
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 268e301775fc..6b94fb7be5f2 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -44,15 +44,12 @@ static int amba_match(struct device *dev, struct device_driver *drv)
 }
 
 #ifdef CONFIG_HOTPLUG
-static int amba_uevent(struct device *dev, char **envp, int nr_env, char *buf, int bufsz)
+static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct amba_device *pcdev = to_amba_device(dev);
-	int retval = 0, i = 0, len = 0;
+	int retval = 0;
 
-	retval = add_uevent_var(envp, nr_env, &i,
-				buf, bufsz, &len,
-				"AMBA_ID=%08x", pcdev->periphid);
-	envp[i] = NULL;
+	retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
 	return retval;
 }
 #else
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 4d2222618b78..ecd6336bffea 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -180,8 +180,7 @@ static void class_device_create_release(struct class_device *class_dev)
 
 /* needed to allow these devices to have parent class devices */
 static int class_device_create_uevent(struct class_device *class_dev,
-				       char **envp, int num_envp,
-				       char *buffer, int buffer_size)
+				      struct kobj_uevent_env *env)
 {
 	pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 	return 0;
@@ -403,64 +402,43 @@ static void remove_deprecated_class_device_links(struct class_device *cd)
 { }
 #endif
 
-static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
-			 int num_envp, char *buffer, int buffer_size)
+static int class_uevent(struct kset *kset, struct kobject *kobj,
+			struct kobj_uevent_env *env)
 {
 	struct class_device *class_dev = to_class_dev(kobj);
 	struct device *dev = class_dev->dev;
-	int i = 0;
-	int length = 0;
 	int retval = 0;
 
 	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 
 	if (MAJOR(class_dev->devt)) {
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "MAJOR=%u", MAJOR(class_dev->devt));
+		add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
 
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "MINOR=%u", MINOR(class_dev->devt));
+		add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
 	}
 
 	if (dev) {
 		const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 		if (path) {
-			add_uevent_var(envp, num_envp, &i,
-				       buffer, buffer_size, &length,
-				       "PHYSDEVPATH=%s", path);
+			add_uevent_var(env, "PHYSDEVPATH=%s", path);
 			kfree(path);
 		}
 
 		if (dev->bus)
-			add_uevent_var(envp, num_envp, &i,
-				       buffer, buffer_size, &length,
-				       "PHYSDEVBUS=%s", dev->bus->name);
+			add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
 
 		if (dev->driver)
-			add_uevent_var(envp, num_envp, &i,
-				       buffer, buffer_size, &length,
-				       "PHYSDEVDRIVER=%s", dev->driver->name);
+			add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
 	}
 
-	/* terminate, set to next free slot, shrink available space */
-	envp[i] = NULL;
-	envp = &envp[i];
-	num_envp -= i;
-	buffer = &buffer[length];
-	buffer_size -= length;
-
 	if (class_dev->uevent) {
 		/* have the class device specific function add its stuff */
-		retval = class_dev->uevent(class_dev, envp, num_envp,
-					    buffer, buffer_size);
+		retval = class_dev->uevent(class_dev, env);
 		if (retval)
 			pr_debug("class_dev->uevent() returned %d\n", retval);
 	} else if (class_dev->class->uevent) {
 		/* have the class specific function add its stuff */
-		retval = class_dev->class->uevent(class_dev, envp, num_envp,
-						   buffer, buffer_size);
+		retval = class_dev->class->uevent(class_dev, env);
 		if (retval)
 			pr_debug("class->uevent() returned %d\n", retval);
 	}
diff --git a/drivers/base/core.c b/drivers/base/core.c
index ec86d6fc2360..d487c032dc4a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -141,33 +141,23 @@ static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
 	return NULL;
 }
 
-static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
-			int num_envp, char *buffer, int buffer_size)
+static int dev_uevent(struct kset *kset, struct kobject *kobj,
+		      struct kobj_uevent_env *env)
 {
 	struct device *dev = to_dev(kobj);
-	int i = 0;
-	int length = 0;
 	int retval = 0;
 
 	/* add the major/minor if present */
 	if (MAJOR(dev->devt)) {
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "MAJOR=%u", MAJOR(dev->devt));
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "MINOR=%u", MINOR(dev->devt));
+		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
+		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
 	}
 
 	if (dev->type && dev->type->name)
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "DEVTYPE=%s", dev->type->name);
+		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
 
 	if (dev->driver)
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "DRIVER=%s", dev->driver->name);
+		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
 
 #ifdef CONFIG_SYSFS_DEPRECATED
 	if (dev->class) {
@@ -181,59 +171,43 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 
 			path = kobject_get_path(&parent->kobj, GFP_KERNEL);
 			if (path) {
-				add_uevent_var(envp, num_envp, &i,
-					       buffer, buffer_size, &length,
-					       "PHYSDEVPATH=%s", path);
+				add_uevent_var(env, "PHYSDEVPATH=%s", path);
 				kfree(path);
 			}
 
-			add_uevent_var(envp, num_envp, &i,
-				       buffer, buffer_size, &length,
-				       "PHYSDEVBUS=%s", parent->bus->name);
+			add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
 
 			if (parent->driver)
-				add_uevent_var(envp, num_envp, &i,
-					       buffer, buffer_size, &length,
-					       "PHYSDEVDRIVER=%s", parent->driver->name);
+				add_uevent_var(env, "PHYSDEVDRIVER=%s",
+					       parent->driver->name);
 		}
 	} else if (dev->bus) {
-		add_uevent_var(envp, num_envp, &i,
-			       buffer, buffer_size, &length,
-			       "PHYSDEVBUS=%s", dev->bus->name);
+		add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
 
 		if (dev->driver)
-			add_uevent_var(envp, num_envp, &i,
-				       buffer, buffer_size, &length,
-				       "PHYSDEVDRIVER=%s", dev->driver->name);
+			add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
 	}
 #endif
 
-	/* terminate, set to next free slot, shrink available space */
-	envp[i] = NULL;
-	envp = &envp[i];
-	num_envp -= i;
-	buffer = &buffer[length];
-	buffer_size -= length;
-
+	/* have the bus specific function add its stuff */
 	if (dev->bus && dev->bus->uevent) {
-		/* have the bus specific function add its stuff */
-		retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
+		retval = dev->bus->uevent(dev, env);
 		if (retval)
 			pr_debug ("%s: bus uevent() returned %d\n",
 				  __FUNCTION__, retval);
 	}
 
+	/* have the class specific function add its stuff */
 	if (dev->class && dev->class->dev_uevent) {
-		/* have the class specific function add its stuff */
-		retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
+		retval = dev->class->dev_uevent(dev, env);
 		if (retval)
 			pr_debug("%s: class uevent() returned %d\n",
 				 __FUNCTION__, retval);
 	}
 
+	/* have the device type specific fuction add its stuff */
 	if (dev->type && dev->type->uevent) {
-		/* have the device type specific fuction add its stuff */
-		retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size);
+		retval = dev->type->uevent(dev, env);
 		if (retval)
 			pr_debug("%s: dev_type uevent() returned %d\n",
 				 __FUNCTION__, retval);
@@ -253,9 +227,7 @@ static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
 {
 	struct kobject *top_kobj;
 	struct kset *kset;
-	char *envp[32];
-	char *data = NULL;
-	char *pos;
+	struct kobj_uevent_env *env = NULL;
 	int i;
 	size_t count = 0;
 	int retval;
@@ -278,26 +250,20 @@ static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
 		if (!kset->uevent_ops->filter(kset, &dev->kobj))
 			goto out;
 
-	data = (char *)get_zeroed_page(GFP_KERNEL);
-	if (!data)
+	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
+	if (!env)
 		return -ENOMEM;
 
 	/* let the kset specific function add its keys */
-	pos = data;
-	memset(envp, 0, sizeof(envp));
-	retval = kset->uevent_ops->uevent(kset, &dev->kobj,
-					  envp, ARRAY_SIZE(envp),
-					  pos, PAGE_SIZE);
+	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
 	if (retval)
 		goto out;
 
 	/* copy keys to file */
-	for (i = 0; envp[i]; i++) {
-		pos = &buf[count];
-		count += sprintf(pos, "%s\n", envp[i]);
-	}
+	for (i = 0; i < env->envp_idx; i++)
+		count += sprintf(&buf[count], "%s\n", env->envp[i]);
 out:
-	free_page((unsigned long)data);
+	kfree(env);
 	return count;
 }
 
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b24efd4e3e3d..4a1b9bfc5471 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -88,19 +88,14 @@ static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
 
 static void fw_dev_release(struct device *dev);
 
-static int firmware_uevent(struct device *dev, char **envp, int num_envp,
-			   char *buffer, int buffer_size)
+static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
-	int i = 0, len = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			   "FIRMWARE=%s", fw_priv->fw_id))
+	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 		return -ENOMEM;
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			   "TIMEOUT=%i", loading_timeout))
+	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 		return -ENOMEM;
-	envp[i] = NULL;
 
 	return 0;
 }
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 74b96795d2f5..cb99daeae936 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -34,8 +34,7 @@ static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)
 	return MEMORY_CLASS_NAME;
 }
 
-static int memory_uevent(struct kset *kset, struct kobject *kobj, char **envp,
-			int num_envp, char *buffer, int buffer_size)
+static int memory_uevent(struct kset *kset, struct kobj_uevent_env *env)
 {
 	int retval = 0;
 
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9bfc434d1327..a2e3910196e0 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -529,13 +529,11 @@ static struct device_attribute platform_dev_attrs[] = {
 	__ATTR_NULL,
 };
 
-static int platform_uevent(struct device *dev, char **envp, int num_envp,
-		char *buffer, int buffer_size)
+static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct platform_device	*pdev = to_platform_device(dev);
 
-	envp[0] = buffer;
-	snprintf(buffer, buffer_size, "MODALIAS=platform:%s", pdev->name);
+	add_uevent_var(env, "MODALIAS=platform:%s", pdev->name);
 	return 0;
 }
 
diff --git a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
index d944647c82c2..4d4a47393909 100644
--- a/drivers/eisa/eisa-bus.c
+++ b/drivers/eisa/eisa-bus.c
@@ -128,16 +128,11 @@ static int eisa_bus_match (struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-static int eisa_bus_uevent(struct device *dev, char **envp, int num_envp,
-			   char *buffer, int buffer_size)
+static int eisa_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct eisa_device *edev = to_eisa_device(dev);
-	int i = 0;
-	int length = 0;
 
-	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-		       "MODALIAS=" EISA_DEVICE_MODALIAS_FMT, edev->id.sig);
-	envp[i] = NULL;
+	add_uevent_var(env, "MODALIAS=" EISA_DEVICE_MODALIAS_FMT, edev->id.sig);
 	return 0;
 }
 
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index 2b6586341635..56681b3b297b 100644
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -130,23 +130,16 @@ static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 }
 
 static int
-fw_unit_uevent(struct device *dev, char **envp, int num_envp,
-	       char *buffer, int buffer_size)
+fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct fw_unit *unit = fw_unit(dev);
 	char modalias[64];
-	int length = 0;
-	int i = 0;
 
 	get_modalias(unit, modalias, sizeof(modalias));
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "MODALIAS=%s", modalias))
+	if (add_uevent_var(env, "MODALIAS=%s", modalias))
 		return -ENOMEM;
 
-	envp[i] = NULL;
-
 	return 0;
 }
 
diff --git a/drivers/firmware/dmi-id.c b/drivers/firmware/dmi-id.c
index 59c3b5aa89f4..2678098d4504 100644
--- a/drivers/firmware/dmi-id.c
+++ b/drivers/firmware/dmi-id.c
@@ -134,14 +134,17 @@ static struct attribute_group* sys_dmi_attribute_groups[] = {
 	NULL
 };
 
-static int dmi_dev_uevent(struct device *dev, char **envp,
-			    int num_envp, char *buffer, int buffer_size)
+static int dmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	strcpy(buffer, "MODALIAS=");
-	get_modalias(buffer+9, buffer_size-9);
-	envp[0] = buffer;
-	envp[1] = NULL;
-
+	ssize_t len;
+
+	if (add_uevent_var(env, "MODALIAS="))
+		return -ENOMEM;
+	len = get_modalias(&env->buf[env->buflen - 1],
+			   sizeof(env->buf) - env->buflen);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+	env->buflen += len;
 	return 0;
 }
 
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index d663e6960d93..910a62de190d 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -67,20 +67,16 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
 #ifdef	CONFIG_HOTPLUG
 
 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
-static int i2c_device_uevent(struct device *dev, char **envp, int num_envp,
-		      char *buffer, int buffer_size)
+static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct i2c_client	*client = to_i2c_client(dev);
-	int			i = 0, length = 0;
 
 	/* by definition, legacy drivers can't hotplug */
 	if (dev->driver || !client->driver_name)
 		return 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-			"MODALIAS=%s", client->driver_name))
+	if (add_uevent_var(env, "MODALIAS=%s", client->driver_name))
 		return -ENOMEM;
-	envp[i] = NULL;
 	dev_dbg(dev, "uevent\n");
 	return 0;
 }
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index e96212ce5729..a96a8b1b3539 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1663,20 +1663,13 @@ static struct device_attribute ide_dev_attrs[] = {
 	__ATTR_NULL
 };
 
-static int ide_uevent(struct device *dev, char **envp, int num_envp,
-		      char *buffer, int buffer_size)
+static int ide_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	ide_drive_t *drive = to_ide_device(dev);
-	int i = 0;
-	int length = 0;
-
-	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-		       "MEDIA=%s", media_string(drive));
-	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-		       "DRIVENAME=%s", drive->name);
-	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-		       "MODALIAS=ide:m-%s", media_string(drive));
-	envp[i] = NULL;
+
+	add_uevent_var(env, "MEDIA=%s", media_string(drive));
+	add_uevent_var(env, "DRIVENAME=%s", drive->name);
+	add_uevent_var(env, "MODALIAS=ide:m-%s", media_string(drive));
 	return 0;
 }
 
diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index 2ffd53461db6..1939fee616ec 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -153,8 +153,7 @@ struct host_info {
 };
 
 static int nodemgr_bus_match(struct device * dev, struct device_driver * drv);
-static int nodemgr_uevent(struct device *dev, char **envp, int num_envp,
-			  char *buffer, int buffer_size);
+static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env);
 static void nodemgr_resume_ne(struct node_entry *ne);
 static void nodemgr_remove_ne(struct node_entry *ne);
 static struct node_entry *find_entry_by_guid(u64 guid);
@@ -1160,12 +1159,9 @@ static void nodemgr_process_root_directory(struct host_info *hi, struct node_ent
 
 #ifdef CONFIG_HOTPLUG
 
-static int nodemgr_uevent(struct device *dev, char **envp, int num_envp,
-			  char *buffer, int buffer_size)
+static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct unit_directory *ud;
-	int i = 0;
-	int length = 0;
 	int retval = 0;
 	/* ieee1394:venNmoNspNverN */
 	char buf[8 + 1 + 3 + 8 + 2 + 8 + 2 + 8 + 3 + 8 + 1];
@@ -1180,9 +1176,7 @@ static int nodemgr_uevent(struct device *dev, char **envp, int num_envp,
 
 #define PUT_ENVP(fmt,val) 					\
 do {								\
-	retval = add_uevent_var(envp, num_envp, &i,		\
-				buffer, buffer_size, &length,	\
-				fmt, val);			\
+	retval = add_uevent_var(env, fmt, val);		\
 	if (retval)						\
 		return retval;					\
 } while (0)
@@ -1201,15 +1195,12 @@ do {								\
 
 #undef PUT_ENVP
 
-	envp[i] = NULL;
-
 	return 0;
 }
 
 #else
 
-static int nodemgr_uevent(struct device *dev, char **envp, int num_envp,
-			  char *buffer, int buffer_size)
+static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/infiniband/core/sysfs.c b/drivers/infiniband/core/sysfs.c
index 70b77ae67422..3d4050681325 100644
--- a/drivers/infiniband/core/sysfs.c
+++ b/drivers/infiniband/core/sysfs.c
@@ -434,21 +434,18 @@ static void ib_device_release(struct class_device *cdev)
 	kfree(dev);
 }
 
-static int ib_device_uevent(struct class_device *cdev, char **envp,
-			    int num_envp, char *buf, int size)
+static int ib_device_uevent(struct class_device *cdev,
+			    struct kobj_uevent_env *env)
 {
 	struct ib_device *dev = container_of(cdev, struct ib_device, class_dev);
-	int i = 0, len = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buf, size, &len,
-			   "NAME=%s", dev->name))
+	if (add_uevent_var(env, "NAME=%s", dev->name))
 		return -ENOMEM;
 
 	/*
 	 * It would be nice to pass the node GUID with the event...
 	 */
 
-	envp[i] = NULL;
 	return 0;
 }
 
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 5fe755586623..5dc361c954e2 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -859,87 +859,66 @@ static void input_dev_release(struct device *device)
  * Input uevent interface - loading event handlers based on
  * device bitfields.
  */
-static int input_add_uevent_bm_var(char **envp, int num_envp, int *cur_index,
-				   char *buffer, int buffer_size, int *cur_len,
+static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
 				   const char *name, unsigned long *bitmap, int max)
 {
-	if (*cur_index >= num_envp - 1)
-		return -ENOMEM;
-
-	envp[*cur_index] = buffer + *cur_len;
+	int len;
 
-	*cur_len += snprintf(buffer + *cur_len, max(buffer_size - *cur_len, 0), name);
-	if (*cur_len >= buffer_size)
+	if (add_uevent_var(env, "%s=", name))
 		return -ENOMEM;
 
-	*cur_len += input_print_bitmap(buffer + *cur_len,
-					max(buffer_size - *cur_len, 0),
-					bitmap, max, 0) + 1;
-	if (*cur_len > buffer_size)
+	len = input_print_bitmap(&env->buf[env->buflen - 1],
+				 sizeof(env->buf) - env->buflen,
+				 bitmap, max, 0);
+	if (len >= (sizeof(env->buf) - env->buflen))
 		return -ENOMEM;
 
-	(*cur_index)++;
+	env->buflen += len;
 	return 0;
 }
 
-static int input_add_uevent_modalias_var(char **envp, int num_envp, int *cur_index,
-					 char *buffer, int buffer_size, int *cur_len,
+static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
 					 struct input_dev *dev)
 {
-	if (*cur_index >= num_envp - 1)
-		return -ENOMEM;
-
-	envp[*cur_index] = buffer + *cur_len;
+	int len;
 
-	*cur_len += snprintf(buffer + *cur_len, max(buffer_size - *cur_len, 0),
-			     "MODALIAS=");
-	if (*cur_len >= buffer_size)
+	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;
 
-	*cur_len += input_print_modalias(buffer + *cur_len,
-					 max(buffer_size - *cur_len, 0),
-					 dev, 0) + 1;
-	if (*cur_len > buffer_size)
+	len = input_print_modalias(&env->buf[env->buflen - 1],
+				   sizeof(env->buf) - env->buflen,
+				   dev, 0);
+	if (len >= (sizeof(env->buf) - env->buflen))
 		return -ENOMEM;
 
-	(*cur_index)++;
+	env->buflen += len;
 	return 0;
 }
 
 #define INPUT_ADD_HOTPLUG_VAR(fmt, val...)				\
 	do {								\
-		int err = add_uevent_var(envp, num_envp, &i,		\
-					buffer, buffer_size, &len,	\
-					fmt, val);			\
+		int err = add_uevent_var(env, fmt, val);		\
 		if (err)						\
 			return err;					\
 	} while (0)
 
 #define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max)				\
 	do {								\
-		int err = input_add_uevent_bm_var(envp, num_envp, &i,	\
-					buffer, buffer_size, &len,	\
-					name, bm, max);			\
+		int err = input_add_uevent_bm_var(env, name, bm, max);	\
 		if (err)						\
 			return err;					\
 	} while (0)
 
 #define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev)				\
 	do {								\
-		int err = input_add_uevent_modalias_var(envp,		\
-					num_envp, &i,			\
-					buffer, buffer_size, &len,	\
-					dev);				\
+		int err = input_add_uevent_modalias_var(env, dev);	\
 		if (err)						\
 			return err;					\
 	} while (0)
 
-static int input_dev_uevent(struct device *device, char **envp,
-			    int num_envp, char *buffer, int buffer_size)
+static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
 {
 	struct input_dev *dev = to_input_dev(device);
-	int i = 0;
-	int len = 0;
 
 	INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
 				dev->id.bustype, dev->id.vendor,
@@ -971,7 +950,6 @@ static int input_dev_uevent(struct device *device, char **envp,
 
 	INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
 
-	envp[i] = NULL;
 	return 0;
 }
 
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index 372ca4931194..b3bc15acd3f5 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -876,18 +876,14 @@ static int serio_bus_match(struct device *dev, struct device_driver *drv)
 
 #define SERIO_ADD_UEVENT_VAR(fmt, val...)				\
 	do {								\
-		int err = add_uevent_var(envp, num_envp, &i,	\
-					buffer, buffer_size, &len,	\
-					fmt, val);			\
+		int err = add_uevent_var(env, fmt, val);		\
 		if (err)						\
 			return err;					\
 	} while (0)
 
-static int serio_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
+static int serio_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct serio *serio;
-	int i = 0;
-	int len = 0;
 
 	if (!dev)
 		return -ENODEV;
@@ -900,7 +896,6 @@ static int serio_uevent(struct device *dev, char **envp, int num_envp, char *buf
 	SERIO_ADD_UEVENT_VAR("SERIO_EXTRA=%02x", serio->id.extra);
 	SERIO_ADD_UEVENT_VAR("MODALIAS=serio:ty%02Xpr%02Xid%02Xex%02X",
 				serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);
-	envp[i] = NULL;
 
 	return 0;
 }
@@ -908,7 +903,7 @@ static int serio_uevent(struct device *dev, char **envp, int num_envp, char *buf
 
 #else
 
-static int serio_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
+static int serio_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
index 7a78d6b34738..2ee3c3049e8f 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
@@ -905,8 +905,8 @@ struct pvr2_sysfs *pvr2_sysfs_create(struct pvr2_context *mp,
 }
 
 
-static int pvr2_sysfs_hotplug(struct device *cd,char **envp,
-			      int numenvp,char *buf,int size)
+static int pvr2_sysfs_hotplug(struct device *d,
+			      struct kobj_uevent_env *env)
 {
 	/* Even though we don't do anything here, we still need this function
 	   because sysfs will still try to call it. */
diff --git a/drivers/misc/tifm_core.c b/drivers/misc/tifm_core.c
index d195fb088f4a..8f77949f93dd 100644
--- a/drivers/misc/tifm_core.c
+++ b/drivers/misc/tifm_core.c
@@ -57,16 +57,11 @@ static int tifm_bus_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-static int tifm_uevent(struct device *dev, char **envp, int num_envp,
-		       char *buffer, int buffer_size)
+static int tifm_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct tifm_dev *sock = container_of(dev, struct tifm_dev, dev);
-	int i = 0;
-	int length = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-			   "TIFM_CARD_TYPE=%s",
-			   tifm_media_type_name(sock->type, 1)))
+	if (add_uevent_var(env, "TIFM_CARD_TYPE=%s", tifm_media_type_name(sock->type, 1)))
 		return -ENOMEM;
 
 	return 0;
diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index 8d6f6014870f..b0c22cad9423 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -58,12 +58,11 @@ static int mmc_bus_match(struct device *dev, struct device_driver *drv)
 }
 
 static int
-mmc_bus_uevent(struct device *dev, char **envp, int num_envp, char *buf,
-		int buf_size)
+mmc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct mmc_card *card = dev_to_mmc_card(dev);
 	const char *type;
-	int i = 0, length = 0;
+	int retval = 0;
 
 	switch (card->type) {
 	case MMC_TYPE_MMC:
@@ -80,20 +79,14 @@ mmc_bus_uevent(struct device *dev, char **envp, int num_envp, char *buf,
 	}
 
 	if (type) {
-		if (add_uevent_var(envp, num_envp, &i,
-				buf, buf_size, &length,
-				"MMC_TYPE=%s", type))
-			return -ENOMEM;
+		retval = add_uevent_var(env, "MMC_TYPE=%s", type);
+		if (retval)
+			return retval;
 	}
 
-	if (add_uevent_var(envp, num_envp, &i,
-			buf, buf_size, &length,
-			"MMC_NAME=%s", mmc_card_name(card)))
-		return -ENOMEM;
+	retval = add_uevent_var(env, "MMC_NAME=%s", mmc_card_name(card));
 
-	envp[i] = NULL;
-
-	return 0;
+	return retval;
 }
 
 static int mmc_bus_probe(struct device *dev)
diff --git a/drivers/pci/hotplug.c b/drivers/pci/hotplug.c
index 1c97e7dd130b..2b5352a7dffc 100644
--- a/drivers/pci/hotplug.c
+++ b/drivers/pci/hotplug.c
@@ -3,12 +3,9 @@
 #include <linux/module.h>
 #include "pci.h"
 
-int pci_uevent(struct device *dev, char **envp, int num_envp,
-	       char *buffer, int buffer_size)
+int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct pci_dev *pdev;
-	int i = 0;
-	int length = 0;
 
 	if (!dev)
 		return -ENODEV;
@@ -17,37 +14,24 @@ int pci_uevent(struct device *dev, char **envp, int num_envp,
 	if (!pdev)
 		return -ENODEV;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PCI_CLASS=%04X", pdev->class))
+	if (add_uevent_var(env, "PCI_CLASS=%04X", pdev->class))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PCI_ID=%04X:%04X", pdev->vendor, pdev->device))
+	if (add_uevent_var(env, "PCI_ID=%04X:%04X", pdev->vendor, pdev->device))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PCI_SUBSYS_ID=%04X:%04X", pdev->subsystem_vendor,
+	if (add_uevent_var(env, "PCI_SUBSYS_ID=%04X:%04X", pdev->subsystem_vendor,
 			   pdev->subsystem_device))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PCI_SLOT_NAME=%s", pci_name(pdev)))
+	if (add_uevent_var(env, "PCI_SLOT_NAME=%s", pci_name(pdev)))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "MODALIAS=pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02x",
+	if (add_uevent_var(env, "MODALIAS=pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02x",
 			   pdev->vendor, pdev->device,
 			   pdev->subsystem_vendor, pdev->subsystem_device,
 			   (u8)(pdev->class >> 16), (u8)(pdev->class >> 8),
 			   (u8)(pdev->class)))
 		return -ENOMEM;
-
-	envp[i] = NULL;
-
 	return 0;
 }
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 004bc2487270..f61be3abfdca 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -532,8 +532,7 @@ void pci_dev_put(struct pci_dev *dev)
 }
 
 #ifndef CONFIG_HOTPLUG
-int pci_uevent(struct device *dev, char **envp, int num_envp,
-	       char *buffer, int buffer_size)
+int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4c36e80f6d26..b3a7d5b0f936 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -1,7 +1,6 @@
 /* Functions internal to the PCI core code */
 
-extern int pci_uevent(struct device *dev, char **envp, int num_envp,
-		      char *buffer, int buffer_size);
+extern int pci_uevent(struct device *dev, struct kobj_uevent_env *env);
 extern int pci_create_sysfs_dev_files(struct pci_dev *pdev);
 extern void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
 extern void pci_cleanup_rom(struct pci_dev *dev);
diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index f8b13f0270d7..a0aca46ce877 100644
--- a/drivers/pcmcia/cs.c
+++ b/drivers/pcmcia/cs.c
@@ -907,18 +907,14 @@ int pcmcia_insert_card(struct pcmcia_socket *skt)
 EXPORT_SYMBOL(pcmcia_insert_card);
 
 
-static int pcmcia_socket_uevent(struct device *dev, char **envp,
-			        int num_envp, char *buffer, int buffer_size)
+static int pcmcia_socket_uevent(struct device *dev,
+				struct kobj_uevent_env *env)
 {
 	struct pcmcia_socket *s = container_of(dev, struct pcmcia_socket, dev);
-	int i = 0, length = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-			   &length, "SOCKET_NO=%u", s->sock))
+	if (add_uevent_var(env, "SOCKET_NO=%u", s->sock))
 		return -ENOMEM;
 
-	envp[i] = NULL;
-
 	return 0;
 }
 
diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index a99607142fc8..55baa1f0fcbb 100644
--- a/drivers/pcmcia/ds.c
+++ b/drivers/pcmcia/ds.c
@@ -1064,11 +1064,10 @@ static int pcmcia_bus_match(struct device * dev, struct device_driver * drv) {
 
 #ifdef CONFIG_HOTPLUG
 
-static int pcmcia_bus_uevent(struct device *dev, char **envp, int num_envp,
-			     char *buffer, int buffer_size)
+static int pcmcia_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct pcmcia_device *p_dev;
-	int i, length = 0;
+	int i;
 	u32 hash[4] = { 0, 0, 0, 0};
 
 	if (!dev)
@@ -1083,23 +1082,13 @@ static int pcmcia_bus_uevent(struct device *dev, char **envp, int num_envp,
 		hash[i] = crc32(0, p_dev->prod_id[i], strlen(p_dev->prod_id[i]));
 	}
 
-	i = 0;
-
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "SOCKET_NO=%u",
-			   p_dev->socket->sock))
+	if (add_uevent_var(env, "SOCKET_NO=%u", p_dev->socket->sock))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "DEVICE_NO=%02X",
-			   p_dev->device_no))
+	if (add_uevent_var(env, "DEVICE_NO=%02X", p_dev->device_no))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "MODALIAS=pcmcia:m%04Xc%04Xf%02Xfn%02Xpfn%02X"
+	if (add_uevent_var(env, "MODALIAS=pcmcia:m%04Xc%04Xf%02Xfn%02Xpfn%02X"
 			   "pa%08Xpb%08Xpc%08Xpd%08X",
 			   p_dev->has_manf_id ? p_dev->manf_id : 0,
 			   p_dev->has_card_id ? p_dev->card_id : 0,
@@ -1112,15 +1101,12 @@ static int pcmcia_bus_uevent(struct device *dev, char **envp, int num_envp,
 			   hash[3]))
 		return -ENOMEM;
 
-	envp[i] = NULL;
-
 	return 0;
 }
 
 #else
 
-static int pcmcia_bus_uevent(struct device *dev, char **envp, int num_envp,
-			      char *buffer, int buffer_size)
+static int pcmcia_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/power/power_supply.h b/drivers/power/power_supply.h
index a9880d468ee4..f38ba482be75 100644
--- a/drivers/power/power_supply.h
+++ b/drivers/power/power_supply.h
@@ -14,8 +14,7 @@
 
 extern int power_supply_create_attrs(struct power_supply *psy);
 extern void power_supply_remove_attrs(struct power_supply *psy);
-extern int power_supply_uevent(struct device *dev, char **envp, int num_envp,
-			       char *buffer, int buffer_size);
+extern int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env);
 
 #else
 
diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index de3155b21285..249f61bae639 100644
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -195,11 +195,10 @@ static char *kstruprdup(const char *str, gfp_t gfp)
 	return ret;
 }
 
-int power_supply_uevent(struct device *dev, char **envp, int num_envp,
-			char *buffer, int buffer_size)
+int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct power_supply *psy = dev_get_drvdata(dev);
-	int i = 0, length = 0, ret = 0, j;
+	int ret = 0, j;
 	char *prop_buf;
 	char *attrname;
 
@@ -212,8 +211,7 @@ int power_supply_uevent(struct device *dev, char **envp, int num_envp,
 
 	dev_dbg(dev, "POWER_SUPPLY_NAME=%s\n", psy->name);
 
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-			     &length, "POWER_SUPPLY_NAME=%s", psy->name);
+	ret = add_uevent_var(env, "POWER_SUPPLY_NAME=%s", psy->name);
 	if (ret)
 		return ret;
 
@@ -243,9 +241,7 @@ int power_supply_uevent(struct device *dev, char **envp, int num_envp,
 
 		dev_dbg(dev, "Static prop %s=%s\n", attrname, prop_buf);
 
-		ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-				     &length, "POWER_SUPPLY_%s=%s",
-				     attrname, prop_buf);
+		ret = add_uevent_var(env, "POWER_SUPPLY_%s=%s", attrname, prop_buf);
 		kfree(attrname);
 		if (ret)
 			goto out;
@@ -282,14 +278,11 @@ int power_supply_uevent(struct device *dev, char **envp, int num_envp,
 
 		dev_dbg(dev, "prop %s=%s\n", attrname, prop_buf);
 
-		ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-				     &length, "POWER_SUPPLY_%s=%s",
-				     attrname, prop_buf);
+		ret = add_uevent_var(env, "POWER_SUPPLY_%s=%s", attrname, prop_buf);
 		kfree(attrname);
 		if (ret)
 			goto out;
 	}
-	envp[i] = NULL;
 
 out:
 	free_page((unsigned long)prop_buf);
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index b0a18f5176aa..5d967c439822 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -44,8 +44,7 @@ ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
 	return 0;
 }
 static int
-ccwgroup_uevent (struct device *dev, char **envp, int num_envp, char *buffer,
-		  int buffer_size)
+ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
 {
 	/* TODO */
 	return 0;
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index e44d92eac8e9..606bb53e9fae 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -78,49 +78,38 @@ static int snprint_alias(char *buf, size_t size,
 
 /* Set up environment variables for ccw device uevent. Return 0 on success,
  * non-zero otherwise. */
-static int ccw_uevent(struct device *dev, char **envp, int num_envp,
-		      char *buffer, int buffer_size)
+static int ccw_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct ccw_device *cdev = to_ccwdev(dev);
 	struct ccw_device_id *id = &(cdev->id);
-	int i = 0;
-	int len = 0;
 	int ret;
 	char modalias_buf[30];
 
 	/* CU_TYPE= */
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			     "CU_TYPE=%04X", id->cu_type);
+	ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
 	if (ret)
 		return ret;
 
 	/* CU_MODEL= */
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			     "CU_MODEL=%02X", id->cu_model);
+	ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
 	if (ret)
 		return ret;
 
 	/* The next two can be zero, that's ok for us */
 	/* DEV_TYPE= */
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			     "DEV_TYPE=%04X", id->dev_type);
+	ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
 	if (ret)
 		return ret;
 
 	/* DEV_MODEL= */
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			     "DEV_MODEL=%02X", id->dev_model);
+	ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
 	if (ret)
 		return ret;
 
 	/* MODALIAS=  */
 	snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
-	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			     "MODALIAS=%s", modalias_buf);
-	if (ret)
-		return ret;
-	envp[i] = NULL;
-	return 0;
+	ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
+	return ret;
 }
 
 struct bus_type ccw_bus_type;
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 90bd22014513..e99713041591 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -458,28 +458,22 @@ static int ap_bus_match(struct device *dev, struct device_driver *drv)
  * uevent function for AP devices. It sets up a single environment
  * variable DEV_TYPE which contains the hardware device type.
  */
-static int ap_uevent (struct device *dev, char **envp, int num_envp,
-		       char *buffer, int buffer_size)
+static int ap_uevent (struct device *dev, struct kobj_uevent_env *env)
 {
 	struct ap_device *ap_dev = to_ap_dev(dev);
-	int retval = 0, length = 0, i = 0;
+	int retval = 0;
 
 	if (!ap_dev)
 		return -ENODEV;
 
 	/* Set up DEV_TYPE environment variable. */
-	retval = add_uevent_var(envp, num_envp, &i,
-				buffer, buffer_size, &length,
-				"DEV_TYPE=%04X", ap_dev->device_type);
+	retval = add_uevent_var(env, "DEV_TYPE=%04X", ap_dev->device_type);
 	if (retval)
 		return retval;
 
 	/* Add MODALIAS= */
-	retval = add_uevent_var(envp, num_envp, &i,
-				buffer, buffer_size, &length,
-				"MODALIAS=ap:t%02X", ap_dev->device_type);
+	retval = add_uevent_var(env, "MODALIAS=ap:t%02X", ap_dev->device_type);
 
-	envp[i] = NULL;
 	return retval;
 }
 
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 34cdce6738a6..ede9986d349a 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -277,16 +277,11 @@ static int scsi_bus_match(struct device *dev, struct device_driver *gendrv)
 	return (sdp->inq_periph_qual == SCSI_INQ_PQ_CON)? 1: 0;
 }
 
-static int scsi_bus_uevent(struct device *dev, char **envp, int num_envp,
-		           char *buffer, int buffer_size)
+static int scsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct scsi_device *sdev = to_scsi_device(dev);
-	int i = 0;
-	int length = 0;
 
-	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-		       "MODALIAS=" SCSI_DEVICE_MODALIAS_FMT, sdev->type);
-	envp[i] = NULL;
+	add_uevent_var(env, "MODALIAS=" SCSI_DEVICE_MODALIAS_FMT, sdev->type);
 	return 0;
 }
 
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e84d21597943..bcb8dd5fb0b4 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -67,14 +67,11 @@ static int spi_match_device(struct device *dev, struct device_driver *drv)
 	return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0;
 }
 
-static int spi_uevent(struct device *dev, char **envp, int num_envp,
-		char *buffer, int buffer_size)
+static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	const struct spi_device		*spi = to_spi_device(dev);
 
-	envp[0] = buffer;
-	snprintf(buffer, buffer_size, "MODALIAS=%s", spi->modalias);
-	envp[1] = NULL;
+	add_uevent_var(env, "MODALIAS=%s", spi->modalias);
 	return 0;
 }
 
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 63b1243a9139..6273a5197e6a 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -576,12 +576,9 @@ static int usb_device_match(struct device *dev, struct device_driver *drv)
 }
 
 #ifdef	CONFIG_HOTPLUG
-static int usb_uevent(struct device *dev, char **envp, int num_envp,
-		      char *buffer, int buffer_size)
+static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct usb_device *usb_dev;
-	int i = 0;
-	int length = 0;
 
 	if (!dev)
 		return -ENODEV;
@@ -610,51 +607,39 @@ static int usb_uevent(struct device *dev, char **envp, int num_envp,
 	 * all the device descriptors we don't tell them about.  Or
 	 * act as usermode drivers.
 	 */
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "DEVICE=/proc/bus/usb/%03d/%03d",
+	if (add_uevent_var(env, "DEVICE=/proc/bus/usb/%03d/%03d",
 			   usb_dev->bus->busnum, usb_dev->devnum))
 		return -ENOMEM;
 #endif
 
 	/* per-device configurations are common */
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PRODUCT=%x/%x/%x",
+	if (add_uevent_var(env, "PRODUCT=%x/%x/%x",
 			   le16_to_cpu(usb_dev->descriptor.idVendor),
 			   le16_to_cpu(usb_dev->descriptor.idProduct),
 			   le16_to_cpu(usb_dev->descriptor.bcdDevice)))
 		return -ENOMEM;
 
 	/* class-based driver binding models */
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "TYPE=%d/%d/%d",
+	if (add_uevent_var(env, "TYPE=%d/%d/%d",
 			   usb_dev->descriptor.bDeviceClass,
 			   usb_dev->descriptor.bDeviceSubClass,
 			   usb_dev->descriptor.bDeviceProtocol))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "BUSNUM=%03d",
+	if (add_uevent_var(env, "BUSNUM=%03d",
 			   usb_dev->bus->busnum))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "DEVNUM=%03d",
+	if (add_uevent_var(env, "DEVNUM=%03d",
 			   usb_dev->devnum))
 		return -ENOMEM;
 
-	envp[i] = NULL;
 	return 0;
 }
 
 #else
 
-static int usb_uevent(struct device *dev, char **envp,
-		      int num_envp, char *buffer, int buffer_size)
+static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index d8f7b089a8f0..95a49d8efe7a 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1339,14 +1339,11 @@ void usb_release_interface(struct device *dev)
 }
 
 #ifdef	CONFIG_HOTPLUG
-static int usb_if_uevent(struct device *dev, char **envp, int num_envp,
-		 char *buffer, int buffer_size)
+static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct usb_device *usb_dev;
 	struct usb_interface *intf;
 	struct usb_host_interface *alt;
-	int i = 0;
-	int length = 0;
 
 	if (!dev)
 		return -ENODEV;
@@ -1359,39 +1356,30 @@ static int usb_if_uevent(struct device *dev, char **envp, int num_envp,
 	alt = intf->cur_altsetting;
 
 #ifdef CONFIG_USB_DEVICEFS
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "DEVICE=/proc/bus/usb/%03d/%03d",
+	if (add_uevent_var(env, "DEVICE=/proc/bus/usb/%03d/%03d",
 			   usb_dev->bus->busnum, usb_dev->devnum))
 		return -ENOMEM;
 #endif
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "PRODUCT=%x/%x/%x",
+	if (add_uevent_var(env, "PRODUCT=%x/%x/%x",
 			   le16_to_cpu(usb_dev->descriptor.idVendor),
 			   le16_to_cpu(usb_dev->descriptor.idProduct),
 			   le16_to_cpu(usb_dev->descriptor.bcdDevice)))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "TYPE=%d/%d/%d",
+	if (add_uevent_var(env, "TYPE=%d/%d/%d",
 			   usb_dev->descriptor.bDeviceClass,
 			   usb_dev->descriptor.bDeviceSubClass,
 			   usb_dev->descriptor.bDeviceProtocol))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-		   buffer, buffer_size, &length,
-		   "INTERFACE=%d/%d/%d",
+	if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
 		   alt->desc.bInterfaceClass,
 		   alt->desc.bInterfaceSubClass,
 		   alt->desc.bInterfaceProtocol))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-		   buffer, buffer_size, &length,
+	if (add_uevent_var(env,
 		   "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
 		   le16_to_cpu(usb_dev->descriptor.idVendor),
 		   le16_to_cpu(usb_dev->descriptor.idProduct),
@@ -1404,14 +1392,12 @@ static int usb_if_uevent(struct device *dev, char **envp, int num_envp,
 		   alt->desc.bInterfaceProtocol))
 		return -ENOMEM;
 
-	envp[i] = NULL;
 	return 0;
 }
 
 #else
 
-static int usb_if_uevent(struct device *dev, char **envp,
-			 int num_envp, char *buffer, int buffer_size)
+static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return -ENODEV;
 }
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index a593f900eff4..070217322c9f 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -197,7 +197,7 @@ static struct w1_family w1_default_family = {
 	.fops = &w1_default_fops,
 };
 
-static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
+static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 
 static struct bus_type w1_bus_type = {
 	.name = "w1",
@@ -396,13 +396,12 @@ static void w1_destroy_master_attributes(struct w1_master *master)
 }
 
 #ifdef CONFIG_HOTPLUG
-static int w1_uevent(struct device *dev, char **envp, int num_envp,
-			char *buffer, int buffer_size)
+static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct w1_master *md = NULL;
 	struct w1_slave *sl = NULL;
 	char *event_owner, *name;
-	int err, cur_index=0, cur_len=0;
+	int err;
 
 	if (dev->driver == &w1_master_driver) {
 		md = container_of(dev, struct w1_master, dev);
@@ -423,23 +422,19 @@ static int w1_uevent(struct device *dev, char **envp, int num_envp,
 	if (dev->driver != &w1_slave_driver || !sl)
 		return 0;
 
-	err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
-			&cur_len, "W1_FID=%02X", sl->reg_num.family);
+	err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 	if (err)
 		return err;
 
-	err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size,
-			&cur_len, "W1_SLAVE_ID=%024LX",
-			(unsigned long long)sl->reg_num.id);
-	envp[cur_index] = NULL;
+	err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
+			     (unsigned long long)sl->reg_num.id);
 	if (err)
 		return err;
 
 	return 0;
 };
 #else
-static int w1_uevent(struct device *dev, char **envp, int num_envp,
-			char *buffer, int buffer_size)
+static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	return 0;
 }