Merge tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the driver core patchset for 4.18-rc1.

  The large chunk of these are firmware core documentation and api
  updates. Nothing major there, just better descriptions for others to
  be able to understand the firmware code better. There's also a user
  for a new firmware api call.

  Other than that, there are some minor updates for debugfs, kernfs, and
  the driver core itself.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
  driver core: hold dev's parent lock when needed
  driver-core: return EINVAL error instead of BUG_ON()
  driver core: add __printf verification to device_create_groups_vargs
  mm: memory_hotplug: use put_device() if device_register fail
  base: core: fix typo 'can by' to 'can be'
  debugfs: inode: debugfs_create_dir uses mode permission from parent
  debugfs: Re-use kstrtobool_from_user()
  Documentation: clarify firmware_class provenance and why we can't rename the module
  Documentation: remove stale firmware API reference
  Documentation: fix few typos and clarifications for the firmware loader
  ath10k: re-enable the firmware fallback mechanism for testmode
  ath10k: use firmware_request_nowarn() to load firmware
  firmware: add firmware_request_nowarn() - load firmware without warnings
  firmware_loader: make firmware_fallback_sysfs() print more useful
  firmware_loader: move kconfig FW_LOADER entries to its own file
  firmware_loader: replace ---help--- with help
  firmware_loader: enhance Kconfig documentation over FW_LOADER
  firmware_loader: document firmware_sysfs_fallback()
  firmware: rename fw_sysfs_fallback to firmware_fallback_sysfs()
  firmware: use () to terminate kernel-doc function names
  ...

Author: torvalds

Documentation/dell_rbu.txt

@@ -121,10 +121,7 @@ read back the image downloaded.
 
 .. note::
 
-   This driver requires a patch for firmware_class.c which has the modified
-   request_firmware_nowait function.
-
-   Also after updating the BIOS image a user mode application needs to execute
+   After updating the BIOS image a user mode application needs to execute
    code which sends the BIOS update request to the BIOS. So on the next reboot
    the BIOS knows about the new image downloaded and it updates itself.
    Also don't unload the rbu driver if the image has to be updated.

Documentation/driver-api/firmware/fallback-mechanisms.rst

@@ -72,9 +72,12 @@ the firmware requested, and establishes it in the device hierarchy by
 associating the device used to make the request as the device's parent.
 The sysfs directory's file attributes are defined and controlled through
 the new device's class (firmware_class) and group (fw_dev_attr_groups).
-This is actually where the original firmware_class.c file name comes from,
-as originally the only firmware loading mechanism available was the
-mechanism we now use as a fallback mechanism.
+This is actually where the original firmware_class module name came from,
+given that originally the only firmware loading mechanism available was the
+mechanism we now use as a fallback mechanism, which registers a struct class
+firmware_class. Because the attributes exposed are part of the module name, the
+module name firmware_class cannot be renamed in the future, to ensure backward
+compatibility with old userspace.
 
 To load firmware using the sysfs interface we expose a loading indicator,
 and a file upload firmware into:
@@ -83,7 +86,7 @@ and a file upload firmware into:
   * /sys/$DEVPATH/data
 
 To upload firmware you will echo 1 onto the loading file to indicate
-you are loading firmware. You then cat the firmware into the data file,
+you are loading firmware. You then write the firmware into the data file,
 and you notify the kernel the firmware is ready by echo'ing 0 onto
 the loading file.
 
@@ -136,7 +139,8 @@ by kobject uevents. This is specially exacerbated due to the fact that most
 distributions today disable CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
 
 Refer to do_firmware_uevent() for details of the kobject event variables
-setup. Variables passwdd with a kobject add event:
+setup. The variables currently passed to userspace with a "kobject add"
+event are:
 
 * FIRMWARE=firmware name
 * TIMEOUT=timeout value

Documentation/driver-api/firmware/firmware_cache.rst

@@ -29,8 +29,8 @@ Some implementation details about the firmware cache setup:
 * If an asynchronous call is used the firmware cache is only set up for a
   device if if the second argument (uevent) to request_firmware_nowait() is
   true. When uevent is true it requests that a kobject uevent be sent to
-  userspace for the firmware request. For details refer to the Fackback
-  mechanism documented below.
+  userspace for the firmware request through the sysfs fallback mechanism
+  if the firmware file is not found.
 
 * If the firmware cache is determined to be needed as per the above two
   criteria the firmware cache is setup by adding a devres entry for the

Documentation/driver-api/firmware/request_firmware.rst

@@ -20,6 +20,11 @@ request_firmware
 .. kernel-doc:: drivers/base/firmware_loader/main.c
    :functions: request_firmware
 
+firmware_request_nowarn
+-----------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: firmware_request_nowarn
+
 request_firmware_direct
 -----------------------
 .. kernel-doc:: drivers/base/firmware_loader/main.c

drivers/base/Kconfig

@@ -70,81 +70,25 @@ config STANDALONE
 	  If unsure, say Y.
 
 config PREVENT_FIRMWARE_BUILD
-	bool "Prevent firmware from being built"
+	bool "Disable drivers features which enable custom firmware building"
 	default y
 	help
-	  Say yes to avoid building firmware. Firmware is usually shipped
-	  with the driver and only when updating the firmware should a
-	  rebuild be made.
-	  If unsure, say Y here.
-
-config FW_LOADER
-	tristate "Userspace firmware loading support" if EXPERT
-	default y
-	---help---
-	  This option is provided for the case where none of the in-tree modules
-	  require userspace firmware loading support, but a module built
-	  out-of-tree does.
-
-config EXTRA_FIRMWARE
-	string "External firmware blobs to build into the kernel binary"
-	depends on FW_LOADER
-	help
-	  Various drivers in the kernel source tree may require firmware,
-	  which is generally available in your distribution's linux-firmware
-	  package.
-
-	  The linux-firmware package should install firmware into
-	  /lib/firmware/ on your system, so they can be loaded by userspace
-	  helpers on request.
-
-	  This option allows firmware to be built into the kernel for the case
-	  where the user either cannot or doesn't want to provide it from
-	  userspace at runtime (for example, when the firmware in question is
-	  required for accessing the boot device, and the user doesn't want to
-	  use an initrd).
-
-	  This option is a string and takes the (space-separated) names of the
-	  firmware files -- the same names that appear in MODULE_FIRMWARE()
-	  and request_firmware() in the source. These files should exist under
-	  the directory specified by the EXTRA_FIRMWARE_DIR option, which is
-	  /lib/firmware by default.
-
-	  For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
-	  the usb8388.bin file into /lib/firmware, and build the kernel. Then
-	  any request_firmware("usb8388.bin") will be satisfied internally
-	  without needing to call out to userspace.
-
-	  WARNING: If you include additional firmware files into your binary
-	  kernel image that are not available under the terms of the GPL,
-	  then it may be a violation of the GPL to distribute the resulting
-	  image since it combines both GPL and non-GPL work. You should
-	  consult a lawyer of your own before distributing such an image.
-
-config EXTRA_FIRMWARE_DIR
-	string "Firmware blobs root directory"
-	depends on EXTRA_FIRMWARE != ""
-	default "/lib/firmware"
-	help
-	  This option controls the directory in which the kernel build system
-	  looks for the firmware files listed in the EXTRA_FIRMWARE option.
-
-config FW_LOADER_USER_HELPER
-	bool
-
-config FW_LOADER_USER_HELPER_FALLBACK
-	bool "Fallback user-helper invocation for firmware loading"
-	depends on FW_LOADER
-	select FW_LOADER_USER_HELPER
-	help
-	  This option enables / disables the invocation of user-helper
-	  (e.g. udev) for loading firmware files as a fallback after the
-	  direct file loading in kernel fails.  The user-mode helper is
-	  no longer required unless you have a special firmware file that
-	  resides in a non-standard path. Moreover, the udev support has
-	  been deprecated upstream.
-
-	  If you are unsure about this, say N here.
+	  Say yes to disable driver features which enable building a custom
+	  driver firmware at kernel build time. These drivers do not use the
+	  kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they
+	  use their own custom loading mechanism. The required firmware is
+	  usually shipped with the driver, building the driver firmware
+	  should only be needed if you have an updated firmware source.
+
+	  Firmware should not be being built as part of kernel, these days
+	  you should always prevent this and say Y here. There are only two
+	  old drivers which enable building of its firmware at kernel build
+	  time:
+
+	    o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE
+	    o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE
+
+source "drivers/base/firmware_loader/Kconfig"
 
 config WANT_DEV_COREDUMP
 	bool

drivers/base/bus.c

@@ -184,10 +184,10 @@ static ssize_t unbind_store(struct device_driver *drv, const char *buf,
 
 	dev = bus_find_device_by_name(bus, NULL, buf);
 	if (dev && dev->driver == drv) {
-		if (dev->parent)	/* Needed for USB */
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_lock(dev->parent);
 		device_release_driver(dev);
-		if (dev->parent)
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_unlock(dev->parent);
 		err = count;
 	}
@@ -211,12 +211,12 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf,
 
 	dev = bus_find_device_by_name(bus, NULL, buf);
 	if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
-		if (dev->parent)	/* Needed for USB */
+		if (dev->parent && bus->need_parent_lock)
 			device_lock(dev->parent);
 		device_lock(dev);
 		err = driver_probe_device(drv, dev);
 		device_unlock(dev);
-		if (dev->parent)
+		if (dev->parent && bus->need_parent_lock)
 			device_unlock(dev->parent);
 
 		if (err > 0) {
@@ -735,10 +735,10 @@ static int __must_check bus_rescan_devices_helper(struct device *dev,
 	int ret = 0;
 
 	if (!dev->driver) {
-		if (dev->parent)	/* Needed for USB */
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_lock(dev->parent);
 		ret = device_attach(dev);
-		if (dev->parent)
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_unlock(dev->parent);
 	}
 	return ret < 0 ? ret : 0;
@@ -770,10 +770,10 @@ EXPORT_SYMBOL_GPL(bus_rescan_devices);
 int device_reprobe(struct device *dev)
 {
 	if (dev->driver) {
-		if (dev->parent)        /* Needed for USB */
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_lock(dev->parent);
 		device_release_driver(dev);
-		if (dev->parent)
+		if (dev->parent && dev->bus->need_parent_lock)
 			device_unlock(dev->parent);
 	}
 	return bus_rescan_devices_helper(dev, NULL);

drivers/base/core.c

@@ -1487,7 +1487,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
 
 	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
 	if (!dir)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	dir->class = class;
 	kobject_init(&dir->kobj, &class_dir_ktype);
@@ -1497,7 +1497,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
 	retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
 	if (retval < 0) {
 		kobject_put(&dir->kobj);
-		return NULL;
+		return ERR_PTR(retval);
 	}
 	return &dir->kobj;
 }
@@ -1804,6 +1804,10 @@ int device_add(struct device *dev)
 
 	parent = get_device(dev->parent);
 	kobj = get_device_parent(dev, parent);
+	if (IS_ERR(kobj)) {
+		error = PTR_ERR(kobj);
+		goto parent_error;
+	}
 	if (kobj)
 		dev->kobj.parent = kobj;
 
@@ -1902,6 +1906,7 @@ int device_add(struct device *dev)
 	kobject_del(&dev->kobj);
  Error:
 	cleanup_glue_dir(dev, glue_dir);
+parent_error:
 	put_device(parent);
 name_error:
 	kfree(dev->p);
@@ -2426,7 +2431,7 @@ static void device_create_release(struct device *dev)
 	kfree(dev);
 }
 
-static struct device *
+static __printf(6, 0) struct device *
 device_create_groups_vargs(struct class *class, struct device *parent,
 			   dev_t devt, void *drvdata,
 			   const struct attribute_group **groups,
@@ -2704,7 +2709,7 @@ static int device_move_class_links(struct device *dev,
 /**
  * device_move - moves a device to a new parent
  * @dev: the pointer to the struct device to be moved
- * @new_parent: the new parent of the device (can by NULL)
+ * @new_parent: the new parent of the device (can be NULL)
  * @dpm_order: how to reorder the dpm_list
  */
 int device_move(struct device *dev, struct device *new_parent,
@@ -2721,6 +2726,11 @@ int device_move(struct device *dev, struct device *new_parent,
 	device_pm_lock();
 	new_parent = get_device(new_parent);
 	new_parent_kobj = get_device_parent(dev, new_parent);
+	if (IS_ERR(new_parent_kobj)) {
+		error = PTR_ERR(new_parent_kobj);
+		put_device(new_parent);
+		goto out;
+	}
 
 	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
 		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");

drivers/base/dd.c

@@ -814,13 +814,13 @@ static int __driver_attach(struct device *dev, void *data)
 		return ret;
 	} /* ret > 0 means positive match */
 
-	if (dev->parent)	/* Needed for USB */
+	if (dev->parent && dev->bus->need_parent_lock)
 		device_lock(dev->parent);
 	device_lock(dev);
 	if (!dev->driver)
 		driver_probe_device(drv, dev);
 	device_unlock(dev);
-	if (dev->parent)
+	if (dev->parent && dev->bus->need_parent_lock)
 		device_unlock(dev->parent);
 
 	return 0;
@@ -916,15 +916,15 @@ void device_release_driver_internal(struct device *dev,
 				    struct device_driver *drv,
 				    struct device *parent)
 {
-	if (parent)
+	if (parent && dev->bus->need_parent_lock)
 		device_lock(parent);
 
 	device_lock(dev);
 	if (!drv || drv == dev->driver)
 		__device_release_driver(dev, parent);
 
 	device_unlock(dev);
-	if (parent)
+	if (parent && dev->bus->need_parent_lock)
 		device_unlock(parent);
 }
 

drivers/base/driver.c

@@ -148,7 +148,11 @@ int driver_register(struct device_driver *drv)
 	int ret;
 	struct device_driver *other;
 
-	BUG_ON(!drv->bus->p);
+	if (!drv->bus->p) {
+		pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
+			   drv->name, drv->bus->name);
+		return -EINVAL;
+	}
 
 	if ((drv->bus->probe && drv->probe) ||
 	    (drv->bus->remove && drv->remove) ||