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V4L/DVB (9668): em28xx: fix a race condition with hald
Newer versions of hald tries to open it to call QUERYCAP. Due to the lack of a proper locking, it is possible to open the device before it finishes initialization. This patch adds a lock to avoid this risk, and to protect the list of em28xx devices. While here, remove the uneeded BKL lock. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
cce257109f
commit
818a557eeb
@ -73,6 +73,7 @@ MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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static LIST_HEAD(em28xx_devlist);
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static DEFINE_MUTEX(em28xx_devlist_mutex);
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static unsigned int card[] = {[0 ... (EM28XX_MAXBOARDS - 1)] = UNSET };
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static unsigned int video_nr[] = {[0 ... (EM28XX_MAXBOARDS - 1)] = UNSET };
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@ -1519,7 +1520,7 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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struct em28xx_fh *fh;
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enum v4l2_buf_type fh_type = 0;
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lock_kernel();
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mutex_lock(&em28xx_devlist_mutex);
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list_for_each_entry(h, &em28xx_devlist, devlist) {
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if (h->vdev->minor == minor) {
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dev = h;
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@ -1535,10 +1536,11 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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dev = h;
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}
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}
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if (NULL == dev) {
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unlock_kernel();
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mutex_unlock(&em28xx_devlist_mutex);
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if (NULL == dev)
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return -ENODEV;
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}
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mutex_lock(&dev->lock);
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em28xx_videodbg("open minor=%d type=%s users=%d\n",
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minor, v4l2_type_names[fh_type], dev->users);
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@ -1547,10 +1549,9 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL);
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if (!fh) {
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em28xx_errdev("em28xx-video.c: Out of memory?!\n");
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unlock_kernel();
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mutex_unlock(&dev->lock);
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return -ENOMEM;
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}
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mutex_lock(&dev->lock);
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fh->dev = dev;
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fh->radio = radio;
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fh->type = fh_type;
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@ -1584,7 +1585,6 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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sizeof(struct em28xx_buffer), fh);
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mutex_unlock(&dev->lock);
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unlock_kernel();
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return errCode;
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}
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@ -1871,6 +1871,7 @@ int em28xx_register_extension(struct em28xx_ops *ops)
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{
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struct em28xx *dev = NULL;
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mutex_lock(&em28xx_devlist_mutex);
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mutex_lock(&em28xx_extension_devlist_lock);
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list_add_tail(&ops->next, &em28xx_extension_devlist);
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list_for_each_entry(dev, &em28xx_devlist, devlist) {
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@ -1879,6 +1880,7 @@ int em28xx_register_extension(struct em28xx_ops *ops)
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}
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printk(KERN_INFO "Em28xx: Initialized (%s) extension\n", ops->name);
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mutex_unlock(&em28xx_extension_devlist_lock);
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mutex_unlock(&em28xx_devlist_mutex);
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return 0;
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}
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EXPORT_SYMBOL(em28xx_register_extension);
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@ -1887,6 +1889,7 @@ void em28xx_unregister_extension(struct em28xx_ops *ops)
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{
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struct em28xx *dev = NULL;
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mutex_lock(&em28xx_devlist_mutex);
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list_for_each_entry(dev, &em28xx_devlist, devlist) {
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if (dev)
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ops->fini(dev);
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@ -1896,6 +1899,7 @@ void em28xx_unregister_extension(struct em28xx_ops *ops)
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printk(KERN_INFO "Em28xx: Removed (%s) extension\n", ops->name);
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list_del(&ops->next);
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mutex_unlock(&em28xx_extension_devlist_lock);
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mutex_unlock(&em28xx_devlist_mutex);
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}
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EXPORT_SYMBOL(em28xx_unregister_extension);
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@ -1921,6 +1925,60 @@ static struct video_device *em28xx_vdev_init(struct em28xx *dev,
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}
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static int register_analog_devices(struct em28xx *dev)
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{
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int ret;
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/* allocate and fill video video_device struct */
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dev->vdev = em28xx_vdev_init(dev, &em28xx_video_template, "video");
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if (!dev->vdev) {
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em28xx_errdev("cannot allocate video_device.\n");
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return -ENODEV;
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}
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/* register v4l2 video video_device */
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ret = video_register_device(dev->vdev, VFL_TYPE_GRABBER,
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video_nr[dev->devno]);
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if (ret) {
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em28xx_errdev("unable to register video device (error=%i).\n",
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ret);
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return ret;
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}
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/* Allocate and fill vbi video_device struct */
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dev->vbi_dev = em28xx_vdev_init(dev, &em28xx_video_template, "vbi");
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/* register v4l2 vbi video_device */
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ret = video_register_device(dev->vbi_dev, VFL_TYPE_VBI,
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vbi_nr[dev->devno]);
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if (ret < 0) {
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em28xx_errdev("unable to register vbi device\n");
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return ret;
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}
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if (em28xx_boards[dev->model].radio.type == EM28XX_RADIO) {
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dev->radio_dev = em28xx_vdev_init(dev, &em28xx_radio_template, "radio");
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if (!dev->radio_dev) {
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em28xx_errdev("cannot allocate video_device.\n");
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return -ENODEV;
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}
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ret = video_register_device(dev->radio_dev, VFL_TYPE_RADIO,
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radio_nr[dev->devno]);
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if (ret < 0) {
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em28xx_errdev("can't register radio device\n");
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return ret;
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}
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em28xx_info("Registered radio device as /dev/radio%d\n",
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dev->radio_dev->num);
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}
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em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",
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dev->vdev->num, dev->vbi_dev->num);
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return 0;
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}
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/*
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* em28xx_init_dev()
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* allocates and inits the device structs, registers i2c bus and v4l device
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@ -2000,50 +2058,6 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
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return errCode;
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}
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list_add_tail(&dev->devlist, &em28xx_devlist);
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/* allocate and fill video video_device struct */
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dev->vdev = em28xx_vdev_init(dev, &em28xx_video_template, "video");
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if (NULL == dev->vdev) {
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em28xx_errdev("cannot allocate video_device.\n");
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goto fail_unreg;
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}
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/* register v4l2 video video_device */
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retval = video_register_device(dev->vdev, VFL_TYPE_GRABBER,
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video_nr[dev->devno]);
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if (retval) {
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em28xx_errdev("unable to register video device (error=%i).\n",
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retval);
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goto fail_unreg;
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}
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/* Allocate and fill vbi video_device struct */
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dev->vbi_dev = em28xx_vdev_init(dev, &em28xx_video_template, "vbi");
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/* register v4l2 vbi video_device */
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if (video_register_device(dev->vbi_dev, VFL_TYPE_VBI,
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vbi_nr[dev->devno]) < 0) {
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em28xx_errdev("unable to register vbi device\n");
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retval = -ENODEV;
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goto fail_unreg;
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}
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if (em28xx_boards[dev->model].radio.type == EM28XX_RADIO) {
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dev->radio_dev = em28xx_vdev_init(dev, &em28xx_radio_template, "radio");
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if (NULL == dev->radio_dev) {
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em28xx_errdev("cannot allocate video_device.\n");
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goto fail_unreg;
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}
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retval = video_register_device(dev->radio_dev, VFL_TYPE_RADIO,
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radio_nr[dev->devno]);
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if (retval < 0) {
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em28xx_errdev("can't register radio device\n");
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goto fail_unreg;
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}
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em28xx_info("Registered radio device as /dev/radio%d\n",
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dev->radio_dev->num);
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}
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/* init video dma queues */
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INIT_LIST_HEAD(&dev->vidq.active);
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INIT_LIST_HEAD(&dev->vidq.queued);
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@ -2070,8 +2084,14 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
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video_mux(dev, 0);
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em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",
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dev->vdev->num, dev->vbi_dev->num);
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mutex_lock(&em28xx_devlist_mutex);
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list_add_tail(&dev->devlist, &em28xx_devlist);
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retval = register_analog_devices(dev);
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if (retval < 0) {
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em28xx_release_resources(dev);
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mutex_unlock(&em28xx_devlist_mutex);
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goto fail_reg_devices;
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}
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mutex_lock(&em28xx_extension_devlist_lock);
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if (!list_empty(&em28xx_extension_devlist)) {
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@ -2081,11 +2101,13 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
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}
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}
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mutex_unlock(&em28xx_extension_devlist_lock);
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mutex_unlock(&em28xx_devlist_mutex);
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return 0;
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fail_unreg:
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em28xx_release_resources(dev);
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fail_reg_devices:
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mutex_unlock(&dev->lock);
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return retval;
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}
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