Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 710 insertions, 0 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
new file mode 100644
index 000000000..9129fabed
--- /dev/null
+++ b/drivers/hid/hidraw.c
@@ -0,0 +1,710 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID raw devices, giving access to raw HID events.
+ *
+ * In comparison to hiddev, this device does not process the
+ * hid events at all (no parsing, no lookups). This lets applications
+ * to work on raw hid events as they want to, and avoids a need to
+ * use a transport-specific userspace libhid/libusb libraries.
+ *
+ *  Copyright (c) 2007-2014 Jiri Kosina
+ */
+
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+#include <linux/device.h>
+#include <linux/major.h>
+#include <linux/slab.h>
+#include <linux/hid.h>
+#include <linux/mutex.h>
+#include <linux/sched/signal.h>
+#include <linux/string.h>
+
+#include <linux/hidraw.h>
+
+static int hidraw_major;
+static struct cdev hidraw_cdev;
+static const struct class hidraw_class = {
+	.name = "hidraw",
+};
+static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
+static DECLARE_RWSEM(minors_rwsem);
+
+static inline bool hidraw_is_revoked(struct hidraw_list *list)
+{
+	return list->revoked;
+}
+
+static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
+{
+	struct hidraw_list *list = file->private_data;
+	int ret = 0, len;
+	DECLARE_WAITQUEUE(wait, current);
+
+	if (hidraw_is_revoked(list))
+		return -ENODEV;
+
+	mutex_lock(&list->read_mutex);
+
+	while (ret == 0) {
+		if (list->head == list->tail) {
+			add_wait_queue(&list->hidraw->wait, &wait);
+			set_current_state(TASK_INTERRUPTIBLE);
+
+			while (list->head == list->tail) {
+				if (signal_pending(current)) {
+					ret = -ERESTARTSYS;
+					break;
+				}
+				if (!list->hidraw->exist) {
+					ret = -EIO;
+					break;
+				}
+				if (file->f_flags & O_NONBLOCK) {
+					ret = -EAGAIN;
+					break;
+				}
+
+				/* allow O_NONBLOCK to work well from other threads */
+				mutex_unlock(&list->read_mutex);
+				schedule();
+				mutex_lock(&list->read_mutex);
+				set_current_state(TASK_INTERRUPTIBLE);
+			}
+
+			set_current_state(TASK_RUNNING);
+			remove_wait_queue(&list->hidraw->wait, &wait);
+		}
+
+		if (ret)
+			goto out;
+
+		len = list->buffer[list->tail].len > count ?
+			count : list->buffer[list->tail].len;
+
+		if (list->buffer[list->tail].value) {
+			if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
+				ret = -EFAULT;
+				goto out;
+			}
+			ret = len;
+		}
+
+		kfree(list->buffer[list->tail].value);
+		list->buffer[list->tail].value = NULL;
+		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
+	}
+out:
+	mutex_unlock(&list->read_mutex);
+	return ret;
+}
+
+/*
+ * The first byte of the report buffer is expected to be a report number.
+ */
+static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
+{
+	unsigned int minor = iminor(file_inode(file));
+	struct hid_device *dev;
+	__u8 *buf;
+	int ret = 0;
+
+	lockdep_assert_held(&minors_rwsem);
+
+	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	dev = hidraw_table[minor]->hid;
+
+	if (count > HID_MAX_BUFFER_SIZE) {
+		hid_warn(dev, "pid %d passed too large report\n",
+			 task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (count < 2) {
+		hid_warn(dev, "pid %d passed too short report\n",
+			 task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	buf = memdup_user(buffer, count);
+	if (IS_ERR(buf)) {
+		ret = PTR_ERR(buf);
+		goto out;
+	}
+
+	if ((report_type == HID_OUTPUT_REPORT) &&
+	    !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
+		ret = __hid_hw_output_report(dev, buf, count, (u64)(long)file, false);
+		/*
+		 * compatibility with old implementation of USB-HID and I2C-HID:
+		 * if the device does not support receiving output reports,
+		 * on an interrupt endpoint, fallback to SET_REPORT HID command.
+		 */
+		if (ret != -ENOSYS)
+			goto out_free;
+	}
+
+	ret = __hid_hw_raw_request(dev, buf[0], buf, count, report_type,
+				   HID_REQ_SET_REPORT, (u64)(long)file, false);
+
+out_free:
+	kfree(buf);
+out:
+	return ret;
+}
+
+static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+{
+	struct hidraw_list *list = file->private_data;
+	ssize_t ret;
+	down_read(&minors_rwsem);
+	if (hidraw_is_revoked(list))
+		ret = -ENODEV;
+	else
+		ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
+	up_read(&minors_rwsem);
+	return ret;
+}
+
+
+/*
+ * This function performs a Get_Report transfer over the control endpoint
+ * per section 7.2.1 of the HID specification, version 1.1.  The first byte
+ * of buffer is the report number to request, or 0x0 if the device does not
+ * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
+ * or HID_INPUT_REPORT.
+ */
+static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
+{
+	unsigned int minor = iminor(file_inode(file));
+	struct hid_device *dev;
+	__u8 *buf;
+	int ret = 0, len;
+	unsigned char report_number;
+
+	lockdep_assert_held(&minors_rwsem);
+
+	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	dev = hidraw_table[minor]->hid;
+
+	if (!dev->ll_driver->raw_request) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (count > HID_MAX_BUFFER_SIZE) {
+		hid_warn(dev, "pid %d passed too large report\n",
+			task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (count < 2) {
+		hid_warn(dev, "pid %d passed too short report\n",
+			task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	buf = kmalloc(count, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Read the first byte from the user. This is the report number,
+	 * which is passed to hid_hw_raw_request().
+	 */
+	if (copy_from_user(&report_number, buffer, 1)) {
+		ret = -EFAULT;
+		goto out_free;
+	}
+
+	ret = __hid_hw_raw_request(dev, report_number, buf, count, report_type,
+				   HID_REQ_GET_REPORT, (u64)(long)file, false);
+
+	if (ret < 0)
+		goto out_free;
+
+	len = (ret < count) ? ret : count;
+
+	if (copy_to_user(buffer, buf, len)) {
+		ret = -EFAULT;
+		goto out_free;
+	}
+
+	ret = len;
+
+out_free:
+	kfree(buf);
+out:
+	return ret;
+}
+
+static __poll_t hidraw_poll(struct file *file, poll_table *wait)
+{
+	struct hidraw_list *list = file->private_data;
+	__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
+
+	poll_wait(file, &list->hidraw->wait, wait);
+	if (list->head != list->tail)
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (!list->hidraw->exist || hidraw_is_revoked(list))
+		mask |= EPOLLERR | EPOLLHUP;
+	return mask;
+}
+
+static int hidraw_open(struct inode *inode, struct file *file)
+{
+	unsigned int minor = iminor(inode);
+	struct hidraw *dev;
+	struct hidraw_list *list;
+	unsigned long flags;
+	int err = 0;
+
+	if (!(list = kzalloc_obj(struct hidraw_list))) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Technically not writing to the hidraw_table but a write lock is
+	 * required to protect the device refcount. This is symmetrical to
+	 * hidraw_release().
+	 */
+	down_write(&minors_rwsem);
+	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+		err = -ENODEV;
+		goto out_unlock;
+	}
+
+	dev = hidraw_table[minor];
+	if (!dev->open++) {
+		err = hid_hw_power(dev->hid, PM_HINT_FULLON);
+		if (err < 0) {
+			dev->open--;
+			goto out_unlock;
+		}
+
+		err = hid_hw_open(dev->hid);
+		if (err < 0) {
+			hid_hw_power(dev->hid, PM_HINT_NORMAL);
+			dev->open--;
+			goto out_unlock;
+		}
+	}
+
+	list->hidraw = hidraw_table[minor];
+	mutex_init(&list->read_mutex);
+	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
+	list_add_tail(&list->node, &hidraw_table[minor]->list);
+	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
+	file->private_data = list;
+out_unlock:
+	up_write(&minors_rwsem);
+out:
+	if (err < 0)
+		kfree(list);
+	return err;
+
+}
+
+static int hidraw_fasync(int fd, struct file *file, int on)
+{
+	struct hidraw_list *list = file->private_data;
+
+	if (hidraw_is_revoked(list))
+		return -ENODEV;
+
+	return fasync_helper(fd, file, on, &list->fasync);
+}
+
+static void drop_ref(struct hidraw *hidraw, int exists_bit)
+{
+	if (exists_bit) {
+		hidraw->exist = 0;
+		if (hidraw->open) {
+			hid_hw_close(hidraw->hid);
+			wake_up_interruptible(&hidraw->wait);
+		}
+		device_destroy(&hidraw_class,
+			       MKDEV(hidraw_major, hidraw->minor));
+	} else {
+		--hidraw->open;
+	}
+	if (!hidraw->open) {
+		if (!hidraw->exist) {
+			hidraw_table[hidraw->minor] = NULL;
+			kfree(hidraw);
+		} else {
+			/* close device for last reader */
+			hid_hw_close(hidraw->hid);
+			hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
+		}
+	}
+}
+
+static int hidraw_release(struct inode * inode, struct file * file)
+{
+	unsigned int minor = iminor(inode);
+	struct hidraw_list *list = file->private_data;
+	unsigned long flags;
+
+	down_write(&minors_rwsem);
+
+	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
+	while (list->tail != list->head) {
+		kfree(list->buffer[list->tail].value);
+		list->buffer[list->tail].value = NULL;
+		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
+	}
+	list_del(&list->node);
+	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
+	kfree(list);
+
+	drop_ref(hidraw_table[minor], 0);
+
+	up_write(&minors_rwsem);
+	return 0;
+}
+
+static int hidraw_revoke(struct hidraw_list *list)
+{
+	list->revoked = true;
+
+	return 0;
+}
+
+static long hidraw_fixed_size_ioctl(struct file *file, struct hidraw *dev, unsigned int cmd,
+				    void __user *arg)
+{
+	struct hid_device *hid = dev->hid;
+
+	switch (cmd) {
+		case HIDIOCGRDESCSIZE:
+			if (put_user(hid->rsize, (int __user *)arg))
+				return -EFAULT;
+			break;
+
+		case HIDIOCGRDESC:
+			{
+				__u32 len;
+
+				if (get_user(len, (int __user *)arg))
+					return -EFAULT;
+
+				if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
+					return -EINVAL;
+
+				if (copy_to_user(arg + offsetof(
+				    struct hidraw_report_descriptor,
+				    value[0]),
+				    hid->rdesc,
+				    min(hid->rsize, len)))
+					return -EFAULT;
+
+				break;
+			}
+		case HIDIOCGRAWINFO:
+			{
+				struct hidraw_devinfo dinfo;
+
+				dinfo.bustype = hid->bus;
+				dinfo.vendor = hid->vendor;
+				dinfo.product = hid->product;
+				if (copy_to_user(arg, &dinfo, sizeof(dinfo)))
+					return -EFAULT;
+				break;
+			}
+		case HIDIOCREVOKE:
+			{
+				struct hidraw_list *list = file->private_data;
+
+				if (arg)
+					return -EINVAL;
+
+				return hidraw_revoke(list);
+			}
+		default:
+			/*
+			 * None of the above ioctls can return -EAGAIN, so
+			 * use it as a marker that we need to check variable
+			 * length ioctls.
+			 */
+			return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static long hidraw_rw_variable_size_ioctl(struct file *file, struct hidraw *dev, unsigned int cmd,
+					  void __user *user_arg)
+{
+	int len = _IOC_SIZE(cmd);
+
+	switch (cmd & ~IOCSIZE_MASK) {
+	case HIDIOCSFEATURE(0):
+		return hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
+	case HIDIOCGFEATURE(0):
+		return hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
+	case HIDIOCSINPUT(0):
+		return hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT);
+	case HIDIOCGINPUT(0):
+		return hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT);
+	case HIDIOCSOUTPUT(0):
+		return hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT);
+	case HIDIOCGOUTPUT(0):
+		return hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT);
+	}
+
+	return -EINVAL;
+}
+
+static long hidraw_ro_variable_size_ioctl(struct file *file, struct hidraw *dev, unsigned int cmd,
+					  void __user *user_arg)
+{
+	struct hid_device *hid = dev->hid;
+	int len = _IOC_SIZE(cmd);
+	int field_len;
+
+	switch (cmd & ~IOCSIZE_MASK) {
+	case HIDIOCGRAWNAME(0):
+		field_len = strlen(hid->name) + 1;
+		if (len > field_len)
+			len = field_len;
+		return copy_to_user(user_arg, hid->name, len) ?  -EFAULT : len;
+	case HIDIOCGRAWPHYS(0):
+		field_len = strlen(hid->phys) + 1;
+		if (len > field_len)
+			len = field_len;
+		return copy_to_user(user_arg, hid->phys, len) ?  -EFAULT : len;
+	case HIDIOCGRAWUNIQ(0):
+		field_len = strlen(hid->uniq) + 1;
+		if (len > field_len)
+			len = field_len;
+		return copy_to_user(user_arg, hid->uniq, len) ?  -EFAULT : len;
+	}
+
+	return -EINVAL;
+}
+
+static long hidraw_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(file);
+	unsigned int minor = iminor(inode);
+	struct hidraw *dev;
+	struct hidraw_list *list = file->private_data;
+	void __user *user_arg = (void __user *)arg;
+	int ret;
+
+	down_read(&minors_rwsem);
+	dev = hidraw_table[minor];
+	if (!dev || !dev->exist || hidraw_is_revoked(list)) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (_IOC_TYPE(cmd) != 'H') {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (_IOC_NR(cmd) > HIDIOCTL_LAST || _IOC_NR(cmd) == 0) {
+		ret = -ENOTTY;
+		goto out;
+	}
+
+	ret = hidraw_fixed_size_ioctl(file, dev, cmd, user_arg);
+	if (ret != -EAGAIN)
+		goto out;
+
+	switch (_IOC_DIR(cmd)) {
+	case (_IOC_READ | _IOC_WRITE):
+		ret = hidraw_rw_variable_size_ioctl(file, dev, cmd, user_arg);
+		break;
+	case _IOC_READ:
+		ret = hidraw_ro_variable_size_ioctl(file, dev, cmd, user_arg);
+		break;
+	default:
+		/* Any other IOC_DIR is wrong */
+		ret = -EINVAL;
+	}
+
+out:
+	up_read(&minors_rwsem);
+	return ret;
+}
+
+static const struct file_operations hidraw_ops = {
+	.owner =        THIS_MODULE,
+	.read =         hidraw_read,
+	.write =        hidraw_write,
+	.poll =         hidraw_poll,
+	.open =         hidraw_open,
+	.release =      hidraw_release,
+	.unlocked_ioctl = hidraw_ioctl,
+	.fasync =	hidraw_fasync,
+	.compat_ioctl   = compat_ptr_ioctl,
+	.llseek =	noop_llseek,
+};
+
+int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
+{
+	struct hidraw *dev = hid->hidraw;
+	struct hidraw_list *list;
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->list_lock, flags);
+	list_for_each_entry(list, &dev->list, node) {
+		int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
+
+		if (hidraw_is_revoked(list) || new_head == list->tail)
+			continue;
+
+		if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
+			ret = -ENOMEM;
+			break;
+		}
+		list->buffer[list->head].len = len;
+		list->head = new_head;
+		kill_fasync(&list->fasync, SIGIO, POLL_IN);
+	}
+	spin_unlock_irqrestore(&dev->list_lock, flags);
+
+	wake_up_interruptible(&dev->wait);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hidraw_report_event);
+
+int hidraw_connect(struct hid_device *hid)
+{
+	int minor, result;
+	struct hidraw *dev;
+
+	/* we accept any HID device, all applications */
+
+	dev = kzalloc_obj(struct hidraw);
+	if (!dev)
+		return -ENOMEM;
+
+	result = -EINVAL;
+
+	down_write(&minors_rwsem);
+
+	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
+		if (hidraw_table[minor])
+			continue;
+		hidraw_table[minor] = dev;
+		result = 0;
+		break;
+	}
+
+	if (result) {
+		up_write(&minors_rwsem);
+		kfree(dev);
+		goto out;
+	}
+
+	dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
+				 NULL, "%s%d", "hidraw", minor);
+
+	if (IS_ERR(dev->dev)) {
+		hidraw_table[minor] = NULL;
+		up_write(&minors_rwsem);
+		result = PTR_ERR(dev->dev);
+		kfree(dev);
+		goto out;
+	}
+
+	init_waitqueue_head(&dev->wait);
+	spin_lock_init(&dev->list_lock);
+	INIT_LIST_HEAD(&dev->list);
+
+	dev->hid = hid;
+	dev->minor = minor;
+
+	dev->exist = 1;
+	hid->hidraw = dev;
+
+	up_write(&minors_rwsem);
+out:
+	return result;
+
+}
+EXPORT_SYMBOL_GPL(hidraw_connect);
+
+void hidraw_disconnect(struct hid_device *hid)
+{
+	struct hidraw *hidraw = hid->hidraw;
+
+	down_write(&minors_rwsem);
+
+	drop_ref(hidraw, 1);
+
+	up_write(&minors_rwsem);
+}
+EXPORT_SYMBOL_GPL(hidraw_disconnect);
+
+int __init hidraw_init(void)
+{
+	int result;
+	dev_t dev_id;
+
+	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
+			HIDRAW_MAX_DEVICES, "hidraw");
+	if (result < 0) {
+		pr_warn("can't get major number\n");
+		goto out;
+	}
+
+	hidraw_major = MAJOR(dev_id);
+
+	result = class_register(&hidraw_class);
+	if (result)
+		goto error_cdev;
+
+        cdev_init(&hidraw_cdev, &hidraw_ops);
+	result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
+	if (result < 0)
+		goto error_class;
+
+	pr_info("raw HID events driver (C) Jiri Kosina\n");
+out:
+	return result;
+
+error_class:
+	class_unregister(&hidraw_class);
+error_cdev:
+	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
+	goto out;
+}
+
+void hidraw_exit(void)
+{
+	dev_t dev_id = MKDEV(hidraw_major, 0);
+
+	cdev_del(&hidraw_cdev);
+	class_unregister(&hidraw_class);
+	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
+
+}