Driver core patches for 3.18-rc1

Here's the driver core patches for 3.18-rc1.  Just a few small things,
 and the addition of a new interface to dump firmware "core dumps" to
 userspace through sysfs that the wireless and graphic drivers want to
 use.
 
 All of these have been in linux-next for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core update from Greg KH:
 "Here's the driver core patches for 3.18-rc1.  Just a few small things,
  and the addition of a new interface to dump firmware "core dumps" to
  userspace through sysfs that the wireless and graphic drivers want to
  use.

  All of these have been in linux-next for a while"

* tag 'driver-core-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  dynamic_debug: change __dynamic_<foo>_dbg return types to void
  driver/base/node: remove unnecessary kfree of node struct from unregister_one_node
  devres: Improve devm_kasprintf()/kvasprintf() support
  Documentation: devres: Add missing devm_kstrdup() managed interface
  Documentation: devres: Add missing IRQ functions
  firmware_class: make sure fw requests contain a name
  driver core: Remove kerneldoc from local function
  attribute_container: fix coding style issues
  attribute_container: fix whitespace errors
  drivers/base: Fix length checks in create_syslog_header()/dev_vprintk_emit()
  device coredump: add new device coredump class
  Documentation/sysfs-rules.txt: Add device attribute error code documentation

Documentation/driver-model/devres.txt

@@ -281,7 +281,9 @@ IOMAP
 
 IRQ
   devm_free_irq()
+  devm_request_any_context_irq()
   devm_request_irq()
+  devm_request_threaded_irq()
 
 MDIO
   devm_mdiobus_alloc()
@@ -291,11 +293,14 @@ MDIO
 MEM
   devm_free_pages()
   devm_get_free_pages()
+  devm_kasprintf()
   devm_kcalloc()
   devm_kfree()
   devm_kmalloc()
   devm_kmalloc_array()
   devm_kmemdup()
+  devm_kstrdup()
+  devm_kvasprintf()
   devm_kzalloc()
 
 PCI

Documentation/sysfs-rules.txt

@@ -161,3 +161,24 @@ versions of the sysfs interface.
   the device that matches the expected subsystem. Depending on a specific
   position of a parent device or exposing relative paths using "../" to
   access the chain of parents is a bug in the application.
+
+- When reading and writing sysfs device attribute files, avoid dependency
+  on specific error codes wherever possible. This minimizes coupling to
+  the error handling implementation within the kernel.
+
+  In general, failures to read or write sysfs device attributes shall
+  propagate errors wherever possible. Common errors include, but are not
+  limited to:
+
+  -EIO: The read or store operation is not supported, typically returned by
+        the sysfs system itself if the read or store pointer is NULL.
+
+  -ENXIO: The read or store operation failed
+
+  Error codes will not be changed without good reason, and should a change
+  to error codes result in user-space breakage, it will be fixed, or the
+  the offending change will be reverted.
+
+  Userspace applications can, however, expect the format and contents of
+  the attribute files to remain consistent in the absence of a version
+  attribute change in the context of a given attribute.

MAINTAINERS

@@ -2877,6 +2877,13 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git
 S:	Maintained
 F:	drivers/usb/dwc3/
 
+DEVICE COREDUMP (DEV_COREDUMP)
+M:	Johannes Berg <johannes@sipsolutions.net>
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+F:	drivers/base/devcoredump.c
+F:	include/linux/devcoredump.h
+
 DEVICE FREQUENCY (DEVFREQ)
 M:	MyungJoo Ham <myungjoo.ham@samsung.com>
 M:	Kyungmin Park <kyungmin.park@samsung.com>

drivers/base/Kconfig

@@ -165,6 +165,27 @@ config FW_LOADER_USER_HELPER_FALLBACK
 
 	  If you are unsure about this, say N here.
 
+config WANT_DEV_COREDUMP
+	bool
+	help
+	  Drivers should "select" this option if they desire to use the
+	  device coredump mechanism.
+
+config DISABLE_DEV_COREDUMP
+	bool "Disable device coredump" if EXPERT
+	help
+	  Disable the device coredump mechanism despite drivers wanting to
+	  use it; this allows for more sensitive systems or systems that
+	  don't want to ever access the information to not have the code,
+	  nor keep any data.
+
+	  If unsure, say N.
+
+config DEV_COREDUMP
+	bool
+	default y if WANT_DEV_COREDUMP
+	depends on !DISABLE_DEV_COREDUMP
+
 config DEBUG_DRIVER
 	bool "Driver Core verbose debug messages"
 	depends on DEBUG_KERNEL

drivers/base/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
 obj-$(CONFIG_REGMAP)	+= regmap/
 obj-$(CONFIG_SOC_BUS) += soc.o
 obj-$(CONFIG_PINCTRL) += pinctrl.o
+obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
 

drivers/base/attribute_container.c

@@ -74,7 +74,7 @@ int
 attribute_container_register(struct attribute_container *cont)
 {
 	INIT_LIST_HEAD(&cont->node);
-	klist_init(&cont->containers,internal_container_klist_get,
+	klist_init(&cont->containers, internal_container_klist_get,
 		   internal_container_klist_put);
 
 	mutex_lock(&attribute_container_mutex);
@@ -184,7 +184,7 @@ attribute_container_add_device(struct device *dev,
 		struct klist_node *n = klist_next(iter); \
 		n ? container_of(n, typeof(*pos), member) : \
 			({ klist_iter_exit(iter) ; NULL; }); \
-	}) ) != NULL; )
+	})) != NULL;)
 
 
 /**

drivers/base/core.c

@@ -2007,6 +2007,8 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
 		return 0;
 
 	pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
+	if (pos >= hdrlen)
+		goto overflow;
 
 	/*
 	 * Add device identifier DEVICE=:
@@ -2038,7 +2040,14 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
 				"DEVICE=+%s:%s", subsys, dev_name(dev));
 	}
 
+	if (pos >= hdrlen)
+		goto overflow;
+
 	return pos;
+
+overflow:
+	dev_WARN(dev, "device/subsystem name too long");
+	return 0;
 }
 
 int dev_vprintk_emit(int level, const struct device *dev,

drivers/base/dd.c

@@ -54,7 +54,7 @@ static LIST_HEAD(deferred_probe_active_list);
 static struct workqueue_struct *deferred_wq;
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 
-/**
+/*
  * deferred_probe_work_func() - Retry probing devices in the active list.
  */
 static void deferred_probe_work_func(struct work_struct *work)

drivers/base/devcoredump.c

@@ -0,0 +1,265 @@
+/*
+ * This file is provided under the GPLv2 license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2014 Intel Mobile Communications GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * The full GNU General Public License is included in this distribution
+ * in the file called COPYING.
+ *
+ * Contact Information:
+ *  Intel Linux Wireless <ilw@linux.intel.com>
+ * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+ *
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/devcoredump.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/workqueue.h>
+
+/* if data isn't read by userspace after 5 minutes then delete it */
+#define DEVCD_TIMEOUT	(HZ * 60 * 5)
+
+struct devcd_entry {
+	struct device devcd_dev;
+	const void *data;
+	size_t datalen;
+	struct module *owner;
+	ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+			const void *data, size_t datalen);
+	void (*free)(const void *data);
+	struct delayed_work del_wk;
+	struct device *failing_dev;
+};
+
+static struct devcd_entry *dev_to_devcd(struct device *dev)
+{
+	return container_of(dev, struct devcd_entry, devcd_dev);
+}
+
+static void devcd_dev_release(struct device *dev)
+{
+	struct devcd_entry *devcd = dev_to_devcd(dev);
+
+	devcd->free(devcd->data);
+	module_put(devcd->owner);
+
+	/*
+	 * this seems racy, but I don't see a notifier or such on
+	 * a struct device to know when it goes away?
+	 */
+	if (devcd->failing_dev->kobj.sd)
+		sysfs_delete_link(&devcd->failing_dev->kobj, &dev->kobj,
+				  "devcoredump");
+
+	put_device(devcd->failing_dev);
+	kfree(devcd);
+}
+
+static void devcd_del(struct work_struct *wk)
+{
+	struct devcd_entry *devcd;
+
+	devcd = container_of(wk, struct devcd_entry, del_wk.work);
+
+	device_del(&devcd->devcd_dev);
+	put_device(&devcd->devcd_dev);
+}
+
+static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
+			       struct bin_attribute *bin_attr,
+			       char *buffer, loff_t offset, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct devcd_entry *devcd = dev_to_devcd(dev);
+
+	return devcd->read(buffer, offset, count, devcd->data, devcd->datalen);
+}
+
+static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
+				struct bin_attribute *bin_attr,
+				char *buffer, loff_t offset, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct devcd_entry *devcd = dev_to_devcd(dev);
+
+	mod_delayed_work(system_wq, &devcd->del_wk, 0);
+
+	return count;
+}
+
+static struct bin_attribute devcd_attr_data = {
+	.attr = { .name = "data", .mode = S_IRUSR | S_IWUSR, },
+	.size = 0,
+	.read = devcd_data_read,
+	.write = devcd_data_write,
+};
+
+static struct bin_attribute *devcd_dev_bin_attrs[] = {
+	&devcd_attr_data, NULL,
+};
+
+static const struct attribute_group devcd_dev_group = {
+	.bin_attrs = devcd_dev_bin_attrs,
+};
+
+static const struct attribute_group *devcd_dev_groups[] = {
+	&devcd_dev_group, NULL,
+};
+
+static struct class devcd_class = {
+	.name		= "devcoredump",
+	.owner		= THIS_MODULE,
+	.dev_release	= devcd_dev_release,
+	.dev_groups	= devcd_dev_groups,
+};
+
+static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
+			   const void *data, size_t datalen)
+{
+	if (offset > datalen)
+		return -EINVAL;
+
+	if (offset + count > datalen)
+		count = datalen - offset;
+
+	if (count)
+		memcpy(buffer, ((u8 *)data) + offset, count);
+
+	return count;
+}
+
+/**
+ * dev_coredumpv - create device coredump with vmalloc data
+ * @dev: the struct device for the crashed device
+ * @data: vmalloc data containing the device coredump
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ *
+ * This function takes ownership of the vmalloc'ed data and will free
+ * it when it is no longer used. See dev_coredumpm() for more information.
+ */
+void dev_coredumpv(struct device *dev, const void *data, size_t datalen,
+		   gfp_t gfp)
+{
+	dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, vfree);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpv);
+
+static int devcd_match_failing(struct device *dev, const void *failing)
+{
+	struct devcd_entry *devcd = dev_to_devcd(dev);
+
+	return devcd->failing_dev == failing;
+}
+
+/**
+ * dev_coredumpm - create device coredump with read/free methods
+ * @dev: the struct device for the crashed device
+ * @owner: the module that contains the read/free functions, use %THIS_MODULE
+ * @data: data cookie for the @read/@free functions
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ * @read: function to read from the given buffer
+ * @free: function to free the given buffer
+ *
+ * Creates a new device coredump for the given device. If a previous one hasn't
+ * been read yet, the new coredump is discarded. The data lifetime is determined
+ * by the device coredump framework and when it is no longer needed the @free
+ * function will be called to free the data.
+ */
+void dev_coredumpm(struct device *dev, struct module *owner,
+		   const void *data, size_t datalen, gfp_t gfp,
+		   ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+				   const void *data, size_t datalen),
+		   void (*free)(const void *data))
+{
+	static atomic_t devcd_count = ATOMIC_INIT(0);
+	struct devcd_entry *devcd;
+	struct device *existing;
+
+	existing = class_find_device(&devcd_class, NULL, dev,
+				     devcd_match_failing);
+	if (existing) {
+		put_device(existing);
+		goto free;
+	}
+
+	if (!try_module_get(owner))
+		goto free;
+
+	devcd = kzalloc(sizeof(*devcd), gfp);
+	if (!devcd)
+		goto put_module;
+
+	devcd->owner = owner;
+	devcd->data = data;
+	devcd->datalen = datalen;
+	devcd->read = read;
+	devcd->free = free;
+	devcd->failing_dev = get_device(dev);
+
+	device_initialize(&devcd->devcd_dev);
+
+	dev_set_name(&devcd->devcd_dev, "devcd%d",
+		     atomic_inc_return(&devcd_count));
+	devcd->devcd_dev.class = &devcd_class;
+
+	if (device_add(&devcd->devcd_dev))
+		goto put_device;
+
+	if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
+			      "failing_device"))
+		/* nothing - symlink will be missing */;
+
+	if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
+			      "devcoredump"))
+		/* nothing - symlink will be missing */;
+
+	INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
+	schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
+
+	return;
+ put_device:
+	put_device(&devcd->devcd_dev);
+ put_module:
+	module_put(owner);
+ free:
+	free(data);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpm);
+
+static int __init devcoredump_init(void)
+{
+	return class_register(&devcd_class);
+}
+__initcall(devcoredump_init);
+
+static int devcd_free(struct device *dev, void *data)
+{
+	struct devcd_entry *devcd = dev_to_devcd(dev);
+
+	flush_delayed_work(&devcd->del_wk);
+	return 0;
+}
+
+static void __exit devcoredump_exit(void)
+{
+	class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
+	class_unregister(&devcd_class);
+}
+__exitcall(devcoredump_exit);

drivers/base/devres.c

@@ -817,13 +817,13 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
 EXPORT_SYMBOL_GPL(devm_kstrdup);
 
 /**
- * devm_kvasprintf - Allocate resource managed space
+ * devm_kvasprintf - Allocate resource managed space and format a string
- *			for the formatted string.
+ *		     into that.
  * @dev: Device to allocate memory for
  * @gfp: the GFP mask used in the devm_kmalloc() call when
  *       allocating memory
- * @fmt: the formatted string to duplicate
+ * @fmt: The printf()-style format string
- * @ap: the list of tokens to be placed in the formatted string
+ * @ap: Arguments for the format string
  * RETURNS:
  * Pointer to allocated string on success, NULL on failure.
  */
@@ -849,12 +849,13 @@ char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
 EXPORT_SYMBOL(devm_kvasprintf);
 
 /**
- * devm_kasprintf - Allocate resource managed space
+ * devm_kasprintf - Allocate resource managed space and format a string
- *		and copy an existing formatted string into that
+ *		    into that.
  * @dev: Device to allocate memory for
  * @gfp: the GFP mask used in the devm_kmalloc() call when
  *       allocating memory
- * @fmt: the string to duplicate
+ * @fmt: The printf()-style format string
+ * @...: Arguments for the format string
  * RETURNS:
  * Pointer to allocated string on success, NULL on failure.
  */

drivers/base/firmware_class.c

@@ -1105,6 +1105,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 	if (!firmware_p)
 		return -EINVAL;
 
+	if (!name || name[0] == '\0')
+		return -EINVAL;
+
 	ret = _request_firmware_prepare(&fw, name, device);
 	if (ret <= 0) /* error or already assigned */
 		goto out;

drivers/base/node.c

@@ -603,7 +603,6 @@ void unregister_one_node(int nid)
 		return;
 
 	unregister_node(node_devices[nid]);
-	kfree(node_devices[nid]);
 	node_devices[nid] = NULL;
 }
 

include/linux/devcoredump.h

@@ -0,0 +1,35 @@
+#ifndef __DEVCOREDUMP_H
+#define __DEVCOREDUMP_H
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+
+#ifdef CONFIG_DEV_COREDUMP
+void dev_coredumpv(struct device *dev, const void *data, size_t datalen,
+		   gfp_t gfp);
+
+void dev_coredumpm(struct device *dev, struct module *owner,
+		   const void *data, size_t datalen, gfp_t gfp,
+		   ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+				   const void *data, size_t datalen),
+		   void (*free)(const void *data));
+#else
+static inline void dev_coredumpv(struct device *dev, const void *data,
+				 size_t datalen, gfp_t gfp)
+{
+	vfree(data);
+}
+
+static inline void
+dev_coredumpm(struct device *dev, struct module *owner,
+	      const void *data, size_t datalen, gfp_t gfp,
+	      ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+			      const void *data, size_t datalen),
+	      void (*free)(const void *data))
+{
+	free(data);
+}
+#endif /* CONFIG_DEV_COREDUMP */
+
+#endif /* __DEVCOREDUMP_H */

include/linux/device.h

@@ -607,8 +607,8 @@ extern int devres_release_group(struct device *dev, void *id);
 extern void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp);
 extern char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
 			     va_list ap);
-extern char *devm_kasprintf(struct device *dev, gfp_t gfp,
+extern __printf(3, 4)
-			    const char *fmt, ...);
+char *devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...);
 static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
 {
 	return devm_kmalloc(dev, size, gfp | __GFP_ZERO);

include/linux/dynamic_debug.h

@@ -42,7 +42,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 #if defined(CONFIG_DYNAMIC_DEBUG)
 extern int ddebug_remove_module(const char *mod_name);
 extern __printf(2, 3)
-int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
+void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
 					const char *modname);
@@ -50,15 +50,15 @@ extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
 struct device;
 
 extern __printf(3, 4)
-int __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
+void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
-		      const char *fmt, ...);
+		       const char *fmt, ...);
 
 struct net_device;
 
 extern __printf(3, 4)
-int __dynamic_netdev_dbg(struct _ddebug *descriptor,
+void __dynamic_netdev_dbg(struct _ddebug *descriptor,
-			 const struct net_device *dev,
+			  const struct net_device *dev,
-			 const char *fmt, ...);
+			  const char *fmt, ...);
 
 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
 	static struct _ddebug  __aligned(8)			\

lib/dynamic_debug.c

@@ -537,10 +537,9 @@ static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 	return buf;
 }
 
-int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
+void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 {
 	va_list args;
-	int res;
 	struct va_format vaf;
 	char buf[PREFIX_SIZE];
 
@@ -552,21 +551,17 @@ int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	res = printk(KERN_DEBUG "%s%pV",
+	printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
-		     dynamic_emit_prefix(descriptor, buf), &vaf);
 
 	va_end(args);
-
-	return res;
 }
 EXPORT_SYMBOL(__dynamic_pr_debug);
 
-int __dynamic_dev_dbg(struct _ddebug *descriptor,
+void __dynamic_dev_dbg(struct _ddebug *descriptor,
 		      const struct device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
-	int res;
 
 	BUG_ON(!descriptor);
 	BUG_ON(!fmt);
@@ -577,30 +572,27 @@ int __dynamic_dev_dbg(struct _ddebug *descriptor,
 	vaf.va = &args;
 
 	if (!dev) {
-		res = printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
+		printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
 	} else {
 		char buf[PREFIX_SIZE];
 
-		res = dev_printk_emit(7, dev, "%s%s %s: %pV",
+		dev_printk_emit(7, dev, "%s%s %s: %pV",
-				      dynamic_emit_prefix(descriptor, buf),
+				dynamic_emit_prefix(descriptor, buf),
-				      dev_driver_string(dev), dev_name(dev),
+				dev_driver_string(dev), dev_name(dev),
-				      &vaf);
+				&vaf);
 	}
 
 	va_end(args);
-
-	return res;
 }
 EXPORT_SYMBOL(__dynamic_dev_dbg);
 
 #ifdef CONFIG_NET
 
-int __dynamic_netdev_dbg(struct _ddebug *descriptor,
+void __dynamic_netdev_dbg(struct _ddebug *descriptor,
-			 const struct net_device *dev, const char *fmt, ...)
+			  const struct net_device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
-	int res;
 
 	BUG_ON(!descriptor);
 	BUG_ON(!fmt);
@@ -613,23 +605,21 @@ int __dynamic_netdev_dbg(struct _ddebug *descriptor,
 	if (dev && dev->dev.parent) {
 		char buf[PREFIX_SIZE];
 
-		res = dev_printk_emit(7, dev->dev.parent,
+		dev_printk_emit(7, dev->dev.parent,
-				      "%s%s %s %s%s: %pV",
+				"%s%s %s %s%s: %pV",
-				      dynamic_emit_prefix(descriptor, buf),
+				dynamic_emit_prefix(descriptor, buf),
-				      dev_driver_string(dev->dev.parent),
+				dev_driver_string(dev->dev.parent),
-				      dev_name(dev->dev.parent),
+				dev_name(dev->dev.parent),
-				      netdev_name(dev), netdev_reg_state(dev),
+				netdev_name(dev), netdev_reg_state(dev),
-				      &vaf);
+				&vaf);
 	} else if (dev) {
-		res = printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
+		printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
-			     netdev_reg_state(dev), &vaf);
+		       netdev_reg_state(dev), &vaf);
 	} else {
-		res = printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
+		printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
 	}
 
 	va_end(args);
-
-	return res;
 }
 EXPORT_SYMBOL(__dynamic_netdev_dbg);