V4L/DVB (12541): v4l: remove video_register_device_index

video_register_device_index is never actually called, instead the
stream index number is always calculated automatically.

This patch removes this function and simplifies the internal get_index
function since that can now always just return the first free index.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/video4linux/v4l2-framework.txt

@@ -500,17 +500,11 @@ first free number.
 Whenever a device node is created some attributes are also created for you.
 If you look in /sys/class/video4linux you see the devices. Go into e.g.
 video0 and you will see 'name' and 'index' attributes. The 'name' attribute
-is the 'name' field of the video_device struct. The 'index' attribute is
+is the 'name' field of the video_device struct.
-a device node index that can be assigned by the driver, or that is calculated
-for you.
 
-If you call video_register_device(), then the index is just increased by
+The 'index' attribute is the index of the device node: for each call to
-1 for each device node you register. The first video device node you register
+video_register_device() the index is just increased by 1. The first video
-always starts off with 0.
+device node you register always starts with index 0.
-
-Alternatively you can call video_register_device_index() which is identical
-to video_register_device(), but with an extra index argument. Here you can
-pass a specific index value (between 0 and 31) that should be used.
 
 Users can setup udev rules that utilize the index attribute to make fancy
 device names (e.g. 'mpegX' for MPEG video capture device nodes).
@@ -520,8 +514,7 @@ After the device was successfully registered, then you can use these fields:
 - vfl_type: the device type passed to video_register_device.
 - minor: the assigned device minor number.
 - num: the device kernel number (i.e. the X in videoX).
-- index: the device index number (calculated or set explicitly using
+- index: the device index number.
-  video_register_device_index).
 
 If the registration failed, then you need to call video_device_release()
 to free the allocated video_device struct, or free your own struct if the

drivers/media/video/v4l2-dev.c

@@ -299,32 +299,28 @@ static const struct file_operations v4l2_fops = {
 };
 
 /**
- * get_index - assign stream number based on parent device
+ * get_index - assign stream index number based on parent device
  * @vdev: video_device to assign index number to, vdev->parent should be assigned
- * @num:  -1 if auto assign, requested number otherwise
  *
  * Note that when this is called the new device has not yet been registered
- * in the video_device array.
+ * in the video_device array, but it was able to obtain a minor number.
  *
- * Returns -ENFILE if num is already in use, a free index number if
+ * This means that we can always obtain a free stream index number since
- * successful.
+ * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
+ * use of the video_device array.
+ *
+ * Returns a free index number.
  */
-static int get_index(struct video_device *vdev, int num)
+static int get_index(struct video_device *vdev)
 {
 	/* This can be static since this function is called with the global
 	   videodev_lock held. */
 	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
 	int i;
 
-	if (num >= VIDEO_NUM_DEVICES) {
+	/* Some drivers do not set the parent. In that case always return 0. */
-		printk(KERN_ERR "videodev: %s num is too large\n", __func__);
-		return -EINVAL;
-	}
-
-	/* Some drivers do not set the parent. In that case always return
-	   num or 0. */
 	if (vdev->parent == NULL)
-		return num >= 0 ? num : 0;
+		return 0;
 
 	bitmap_zero(used, VIDEO_NUM_DEVICES);
 
@@ -335,30 +331,15 @@ static int get_index(struct video_device *vdev, int num)
 		}
 	}
 
-	if (num >= 0) {
+	return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
-		if (test_bit(num, used))
-			return -ENFILE;
-		return num;
-	}
-
-	i = find_first_zero_bit(used, VIDEO_NUM_DEVICES);
-	return i == VIDEO_NUM_DEVICES ? -ENFILE : i;
 }
 
-int video_register_device(struct video_device *vdev, int type, int nr)
-{
-	return video_register_device_index(vdev, type, nr, -1);
-}
-EXPORT_SYMBOL(video_register_device);
-
 /**
- *	video_register_device_index - register video4linux devices
+ *	video_register_device - register video4linux devices
  *	@vdev: video device structure we want to register
  *	@type: type of device to register
  *	@nr:   which device number (0 == /dev/video0, 1 == /dev/video1, ...
  *             -1 == first free)
- *	@index: stream number based on parent device;
- *		-1 if auto assign, requested number otherwise
  *
  *	The registration code assigns minor numbers based on the type
  *	requested. -ENFILE is returned in all the device slots for this
@@ -377,8 +358,7 @@ EXPORT_SYMBOL(video_register_device);
  *
  *	%VFL_TYPE_RADIO - A radio card
  */
-int video_register_device_index(struct video_device *vdev, int type, int nr,
+int video_register_device(struct video_device *vdev, int type, int nr)
-					int index)
 {
 	int i = 0;
 	int ret;
@@ -481,14 +461,9 @@ int video_register_device_index(struct video_device *vdev, int type, int nr,
 	set_bit(nr, video_nums[type]);
 	/* Should not happen since we thought this minor was free */
 	WARN_ON(video_device[vdev->minor] != NULL);
-	ret = vdev->index = get_index(vdev, index);
+	vdev->index = get_index(vdev);
 	mutex_unlock(&videodev_lock);
 
-	if (ret < 0) {
-		printk(KERN_ERR "%s: get_index failed\n", __func__);
-		goto cleanup;
-	}
-
 	/* Part 3: Initialize the character device */
 	vdev->cdev = cdev_alloc();
 	if (vdev->cdev == NULL) {
@@ -543,7 +518,7 @@ int video_register_device_index(struct video_device *vdev, int type, int nr,
 	vdev->minor = -1;
 	return ret;
 }
-EXPORT_SYMBOL(video_register_device_index);
+EXPORT_SYMBOL(video_register_device);
 
 /**
  *	video_unregister_device - unregister a video4linux device

include/media/v4l2-dev.h

@@ -100,8 +100,6 @@ struct video_device
 
    Also note that vdev->minor is set to -1 if the registration failed. */
 int __must_check video_register_device(struct video_device *vdev, int type, int nr);
-int __must_check video_register_device_index(struct video_device *vdev,
-						int type, int nr, int index);
 
 /* Unregister video devices. Will do nothing if vdev == NULL or
    vdev->minor < 0. */