Re: [PATCH v2 11/16] media: utilize new cdev_device_add helper function

Hans Verkuil
2017-02-27T09:02:11Z

On 02/26/2017 07:38 AM, Logan Gunthorpe wrote:
> Replace the open coded registration of the cdev and dev with the
> new device_add_cdev() helper. The helper replaces a common pattern by
> taking the proper reference against the parent device and adding both
> the cdev and the device.
>
> Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>

Acked-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

FYI: this patch series didn't turn up at the linux-media mailinglist for some
reason.

Regards,

Hans

> ---
> drivers/media/cec/cec-core.c | 16 ++++------------
> drivers/media/media-devnode.c | 20 +++++---------------
> 2 files changed, 9 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
> index aca3ab8..3e93c1a 100644
> --- a/drivers/media/cec/cec-core.c
> +++ b/drivers/media/cec/cec-core.c
> @@ -137,24 +137,17 @@ static int __must_check cec_devnode_register(struct cec_devnode *devnode,
>
> /* Part 2: Initialize and register the character device */
> cdev_init(&devnode->cdev, &cec_devnode_fops);
> - devnode->cdev.kobj.parent = &devnode->dev.kobj;
> devnode->cdev.owner = owner;
>
> - ret = cdev_add(&devnode->cdev, devnode->dev.devt, 1);
> - if (ret < 0) {
> - pr_err("%s: cdev_add failed\n", __func__);
> + ret = cdev_device_add(&devnode->cdev, &devnode->dev);
> + if (ret) {
> + pr_err("%s: cdev_device_add failed\n", __func__);
> goto clr_bit;
> }
>
> - ret = device_add(&devnode->dev);
> - if (ret)
> - goto cdev_del;
> -
> devnode->registered = true;
> return 0;
>
> -cdev_del:
> - cdev_del(&devnode->cdev);
> clr_bit:
> mutex_lock(&cec_devnode_lock);
> clear_bit(devnode->minor, cec_devnode_nums);
> @@ -190,8 +183,7 @@ static void cec_devnode_unregister(struct cec_devnode *devnode)
> devnode->unregistered = true;
> mutex_unlock(&devnode->lock);
>
> - device_del(&devnode->dev);
> - cdev_del(&devnode->cdev);
> + cdev_device_del(&devnode->cdev, &devnode->dev);
> put_device(&devnode->dev);
> }
>
> diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c
> index f2772ba..fafe520 100644
> --- a/drivers/media/media-devnode.c
> +++ b/drivers/media/media-devnode.c
> @@ -252,31 +252,22 @@ int __must_check media_devnode_register(struct media_device *mdev,
> dev_set_name(&devnode->dev, "media%d", devnode->minor);
> device_initialize(&devnode->dev);
>
> - /* Part 2: Initialize and register the character device */
> + /* Part 2: Initialize the character device */
> cdev_init(&devnode->cdev, &media_devnode_fops);
> devnode->cdev.owner = owner;
> - devnode->cdev.kobj.parent = &devnode->dev.kobj;
>
> - ret = cdev_add(&devnode->cdev, MKDEV(MAJOR(media_dev_t), devnode->minor), 1);
> + /* Part 3: Add the media and char device */
> + ret = cdev_device_add(&devnode->cdev, &devnode->dev);
> if (ret < 0) {
> - pr_err("%s: cdev_add failed\n", __func__);
> + pr_err("%s: cdev_device_add failed\n", __func__);
> goto cdev_add_error;
> }
>
> - /* Part 3: Add the media device */
> - ret = device_add(&devnode->dev);
> - if (ret < 0) {
> - pr_err("%s: device_add failed\n", __func__);
> - goto device_add_error;
> - }
> -
> /* Part 4: Activate this minor. The char device can now be used. */
> set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
>
> return 0;
>
> -device_add_error:
> - cdev_del(&devnode->cdev);
> cdev_add_error:
> mutex_lock(&media_devnode_lock);
> clear_bit(devnode->minor, media_devnode_nums);
> @@ -302,9 +293,8 @@ void media_devnode_unregister(struct media_devnode *devnode)
> {
> mutex_lock(&media_devnode_lock);
> /* Delete the cdev on this minor as well */
> - cdev_del(&devnode->cdev);
> + cdev_device_del(&devnode->cdev, &devnode->dev);
> mutex_unlock(&media_devnode_lock);
> - device_del(&devnode->dev);
> devnode->media_dev = NULL;
> put_device(&devnode->dev);
> }
>

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