HID: hiddev cleanup -- handle all error conditions properly
This is a cleanup of hiddev and fixes the following issues: - thread safety by locking in read & ioctl, introducing a per device mutex - race between ioctl and disconnect, introducing a flag and locking in form of a per low level device mutex - race between open and other methods, making sure only successfully opened devices are put on the list, changing order of events - range checking both upper and lower limits of the minor range - make sure further calls to open fail for unplugged devices even if the device still has opened files - error checking for low level open - possible loss of wakeup events, using standard waiting macros - race in initialisation by moving registration after full initialisation Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Oliver Neukum
Jiri Kosina
parent
42859e0bd2
commit
079034073f
@ -49,6 +49,7 @@
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struct hiddev {
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int exist;
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int open;
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struct mutex existancelock;
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wait_queue_head_t wait;
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struct hid_device *hid;
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struct list_head list;
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@ -63,6 +64,7 @@ struct hiddev_list {
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struct fasync_struct *fasync;
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struct hiddev *hiddev;
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struct list_head node;
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struct mutex thread_lock;
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};
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static struct hiddev *hiddev_table[HIDDEV_MINORS];
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@ -264,29 +266,48 @@ static int hiddev_release(struct inode * inode, struct file * file)
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static int hiddev_open(struct inode *inode, struct file *file)
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{
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struct hiddev_list *list;
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unsigned long flags;
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int res;
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int i = iminor(inode) - HIDDEV_MINOR_BASE;
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if (i >= HIDDEV_MINORS || !hiddev_table[i])
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if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
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return -ENODEV;
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if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
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return -ENOMEM;
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mutex_init(&list->thread_lock);
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list->hiddev = hiddev_table[i];
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spin_lock_irqsave(&list->hiddev->list_lock, flags);
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list_add_tail(&list->node, &hiddev_table[i]->list);
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spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
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file->private_data = list;
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if (!list->hiddev->open++)
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if (list->hiddev->exist)
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usbhid_open(hiddev_table[i]->hid);
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/*
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* no need for locking because the USB major number
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* is shared which usbcore guards against disconnect
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*/
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if (list->hiddev->exist) {
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if (!list->hiddev->open++) {
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res = usbhid_open(hiddev_table[i]->hid);
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if (res < 0) {
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res = -EIO;
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goto bail;
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}
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}
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} else {
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res = -ENODEV;
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goto bail;
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}
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spin_lock_irq(&list->hiddev->list_lock);
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list_add_tail(&list->node, &hiddev_table[i]->list);
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spin_unlock_irq(&list->hiddev->list_lock);
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return 0;
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bail:
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file->private_data = NULL;
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kfree(list->hiddev);
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return res;
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}
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/*
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@ -305,7 +326,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
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DECLARE_WAITQUEUE(wait, current);
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struct hiddev_list *list = file->private_data;
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int event_size;
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int retval = 0;
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int retval;
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event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
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sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
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@ -313,10 +334,14 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
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if (count < event_size)
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return 0;
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/* lock against other threads */
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retval = mutex_lock_interruptible(&list->thread_lock);
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if (retval)
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return -ERESTARTSYS;
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while (retval == 0) {
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if (list->head == list->tail) {
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add_wait_queue(&list->hiddev->wait, &wait);
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set_current_state(TASK_INTERRUPTIBLE);
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prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
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while (list->head == list->tail) {
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if (file->f_flags & O_NONBLOCK) {
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@ -332,35 +357,45 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
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break;
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}
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/* let O_NONBLOCK tasks run */
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mutex_unlock(&list->thread_lock);
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schedule();
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if (mutex_lock_interruptible(&list->thread_lock))
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return -EINTR;
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set_current_state(TASK_INTERRUPTIBLE);
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}
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finish_wait(&list->hiddev->wait, &wait);
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&list->hiddev->wait, &wait);
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}
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if (retval)
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if (retval) {
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mutex_unlock(&list->thread_lock);
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return retval;
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}
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while (list->head != list->tail &&
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retval + event_size <= count) {
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if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
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if (list->buffer[list->tail].field_index !=
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HID_FIELD_INDEX_NONE) {
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if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
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struct hiddev_event event;
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event.hid = list->buffer[list->tail].usage_code;
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event.value = list->buffer[list->tail].value;
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if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event)))
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if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
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mutex_unlock(&list->thread_lock);
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return -EFAULT;
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}
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retval += sizeof(struct hiddev_event);
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}
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} else {
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if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
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(list->flags & HIDDEV_FLAG_REPORT) != 0) {
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if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref)))
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if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
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mutex_unlock(&list->thread_lock);
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return -EFAULT;
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}
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retval += sizeof(struct hiddev_usage_ref);
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}
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}
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@ -368,6 +403,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
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}
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}
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mutex_unlock(&list->thread_lock);
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return retval;
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}
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@ -555,7 +591,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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struct hid_field *field;
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struct usbhid_device *usbhid = hid->driver_data;
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void __user *user_arg = (void __user *)arg;
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int i;
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int i, r;
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/* Called without BKL by compat methods so no BKL taken */
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@ -619,10 +655,22 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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}
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case HIDIOCGSTRING:
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return hiddev_ioctl_string(hiddev, cmd, user_arg);
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mutex_lock(&hiddev->existancelock);
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if (!hiddev->exist)
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r = hiddev_ioctl_string(hiddev, cmd, user_arg);
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else
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r = -ENODEV;
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mutex_unlock(&hiddev->existancelock);
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return r;
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case HIDIOCINITREPORT:
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mutex_lock(&hiddev->existancelock);
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if (!hiddev->exist) {
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mutex_unlock(&hiddev->existancelock);
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return -ENODEV;
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}
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usbhid_init_reports(hid);
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mutex_unlock(&hiddev->existancelock);
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return 0;
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@ -636,8 +684,12 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
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return -EINVAL;
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usbhid_submit_report(hid, report, USB_DIR_IN);
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usbhid_wait_io(hid);
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mutex_lock(&hiddev->existancelock);
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if (hiddev->exist) {
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usbhid_submit_report(hid, report, USB_DIR_IN);
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usbhid_wait_io(hid);
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}
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mutex_unlock(&hiddev->existancelock);
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return 0;
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@ -651,8 +703,12 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
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return -EINVAL;
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usbhid_submit_report(hid, report, USB_DIR_OUT);
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usbhid_wait_io(hid);
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mutex_lock(&hiddev->existancelock);
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if (hiddev->exist) {
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usbhid_submit_report(hid, report, USB_DIR_OUT);
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usbhid_wait_io(hid);
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}
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mutex_unlock(&hiddev->existancelock);
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return 0;
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@ -710,7 +766,13 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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case HIDIOCGUSAGES:
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case HIDIOCSUSAGES:
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case HIDIOCGCOLLECTIONINDEX:
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return hiddev_ioctl_usage(hiddev, cmd, user_arg);
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mutex_lock(&hiddev->existancelock);
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if (hiddev->exist)
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r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
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else
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r = -ENODEV;
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mutex_unlock(&hiddev->existancelock);
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return r;
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case HIDIOCGCOLLECTIONINFO:
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if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
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@ -808,24 +870,23 @@ int hiddev_connect(struct hid_device *hid, unsigned int force)
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if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
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return -1;
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init_waitqueue_head(&hiddev->wait);
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INIT_LIST_HEAD(&hiddev->list);
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spin_lock_init(&hiddev->list_lock);
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mutex_init(&hiddev->existancelock);
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hiddev->hid = hid;
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hiddev->exist = 1;
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retval = usb_register_dev(usbhid->intf, &hiddev_class);
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if (retval) {
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err_hid("Not able to get a minor for this device.");
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kfree(hiddev);
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return -1;
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} else {
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hid->minor = usbhid->intf->minor;
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hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
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}
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init_waitqueue_head(&hiddev->wait);
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INIT_LIST_HEAD(&hiddev->list);
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spin_lock_init(&hiddev->list_lock);
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hiddev->hid = hid;
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hiddev->exist = 1;
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hid->minor = usbhid->intf->minor;
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hid->hiddev = hiddev;
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hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
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return 0;
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}
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@ -839,7 +900,9 @@ void hiddev_disconnect(struct hid_device *hid)
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struct hiddev *hiddev = hid->hiddev;
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struct usbhid_device *usbhid = hid->driver_data;
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mutex_lock(&hiddev->existancelock);
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hiddev->exist = 0;
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mutex_unlock(&hiddev->existancelock);
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hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
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usb_deregister_dev(usbhid->intf, &hiddev_class);
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