diff mbox series

[v4,25/26] media: mc: Enforce one-time registration

Message ID 20240610100530.1107771-26-sakari.ailus@linux.intel.com (mailing list archive)
State New
Headers
Series Media device lifetime management |

Commit Message

Sakari Ailus June 10, 2024, 10:05 a.m. UTC 
  A media devnode may be registered only once. Enforce this by setting the
minor to -1 in init.

Registration initialises the character device and sets up the device name.
These should take place only once during the lifetime of the media device.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/mc/mc-devnode.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Hans Verkuil June 17, 2024, 10:42 a.m. UTC | #1 
On 10/06/2024 12:05, Sakari Ailus wrote:
> A media devnode may be registered only once. Enforce this by setting the
> minor to -1 in init.
> 
> Registration initialises the character device and sets up the device name.
> These should take place only once during the lifetime of the media device.

This has nothing to do with patch 23/26, right?

I would move this to before that patch.

> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Regards,

	Hans

> ---
>  drivers/media/mc/mc-devnode.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
> index 8cb4e0eec17f..758971f310c3 100644
> --- a/drivers/media/mc/mc-devnode.c
> +++ b/drivers/media/mc/mc-devnode.c
> @@ -240,6 +240,7 @@ void media_devnode_init(struct media_devnode *devnode)
>  {
>  	device_initialize(&devnode->dev);
>  	devnode->dev.release = media_devnode_release;
> +	devnode->minor = -1;
>  }
>  
>  int __must_check media_devnode_register(struct media_devnode *devnode,
> @@ -251,6 +252,9 @@ 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);
Sakari Ailus June 18, 2024, 6:39 a.m. UTC | #2 
Hi Hans,

On Mon, Jun 17, 2024 at 12:42:02PM +0200, Hans Verkuil wrote:
> On 10/06/2024 12:05, Sakari Ailus wrote:
> > A media devnode may be registered only once. Enforce this by setting the
> > minor to -1 in init.
> > 
> > Registration initialises the character device and sets up the device name.
> > These should take place only once during the lifetime of the media device.
> 
> This has nothing to do with patch 23/26, right?
> 
> I would move this to before that patch.

Sounds good.

> 
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> 
> Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Thanks!
diff mbox series

Patch

diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index 8cb4e0eec17f..758971f310c3 100644
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -240,6 +240,7 @@  void media_devnode_init(struct media_devnode *devnode)
 {
 	device_initialize(&devnode->dev);
 	devnode->dev.release = media_devnode_release;
+	devnode->minor = -1;
 }
 
 int __must_check media_devnode_register(struct media_devnode *devnode,
@@ -251,6 +252,9 @@  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);