[PATCH v2 15/29] media: mc: Unassign minor only if it has been assigned

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

Assign the media device minor to -1 if it has not been previously
assigned. There's no dependence to this yes but it will be required by
patch "media: mc: Implement best effort media device removal safety sans
refcount" soon.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
 drivers/media/mc/mc-devnode.c | 9 ++++++++-
 include/media/media-devnode.h | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index 717408791a7c..5057c48f8870 100644
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -59,7 +59,8 @@ static void media_devnode_release(struct device *cd)
 {
 	struct media_devnode *devnode = to_media_devnode(cd);
 
-	media_devnode_free_minor(devnode->minor);
+	if (devnode->minor != -1)
+		media_devnode_free_minor(devnode->minor);
 
 	/* Release media_devnode and perform other cleanups as needed. */
 	if (devnode->release)
@@ -212,6 +213,7 @@ static const struct file_operations media_devnode_fops = {
 void media_devnode_init(struct media_devnode *devnode)
 {
 	device_initialize(&devnode->dev);
+	devnode->minor = -1;
 }
 
 int __must_check media_devnode_register(struct media_devnode *devnode,
@@ -220,6 +222,9 @@ int __must_check media_devnode_register(struct media_devnode *devnode,
 	int minor;
 	int ret;
 
+	if (devnode->minor != -1)
+		return -EINVAL;
+
 	/* Part 1: Find a free minor number */
 	mutex_lock(&media_devnode_lock);
 	minor = find_first_zero_bit(media_devnode_nums, MEDIA_NUM_DEVICES);
@@ -261,6 +266,8 @@ int __must_check media_devnode_register(struct media_devnode *devnode,
 cdev_add_error:
 	media_devnode_free_minor(devnode->minor);
 
+	devnode->minor = -1;
+
 	return ret;
 }
 
diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
index 6d46c658be21..d050f54f252a 100644
--- a/include/media/media-devnode.h
+++ b/include/media/media-devnode.h
@@ -60,7 +60,7 @@ struct media_file_operations {
  * @dev:	pointer to struct &device containing the media controller device
  * @cdev:	struct cdev pointer character device
  * @parent:	parent device
- * @minor:	device node minor number
+ * @minor:	device node minor number, -1 if unassigned
  * @flags:	flags, combination of the ``MEDIA_FLAG_*`` constants
  * @release:	release callback called at the end of ``media_devnode_release()``
  *		routine at media-device.c.
-- 
2.39.2