Hi Hans,
On Fri, Jul 24, 2015 at 12:21:32PM +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Add new helper functions that report back if this was the first open
> or last close.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
...
> @@ -65,11 +65,23 @@ void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
> */
> bool v4l2_fh_add(struct v4l2_fh *fh);
> /*
> + * It allocates a v4l2_fh and inits and adds it to the video_device associated
> + * with the file pointer. In addition it returns true if this was the first
> + * open and false otherwise. The error code is returned in *err.
> + */
> +bool v4l2_fh_open_is_first(struct file *filp, int *err);
The new interface functions look a tad clumsy to me.
What would you think of returning the singularity value from v4l2_fh_open()
straight away? Negative integers are errors, so zero and positive values are
free.
A few drivers just check if the value is non-zero and then return that
value, but there are just a handful of those.
> +/*
> * Can be used as the open() op of v4l2_file_operations.
> * It allocates a v4l2_fh and inits and adds it to the video_device associated
> * with the file pointer.
> */
> -int v4l2_fh_open(struct file *filp);
> +static inline int v4l2_fh_open(struct file *filp)
> +{
> + int err;
> +
> + v4l2_fh_open_is_first(filp, &err);
> + return err;
> +}
> /*
> * Remove file handle from the list of file handles. Must be called in
> * v4l2_file_operations->release() handler if the driver uses v4l2_fh.
> @@ -86,12 +98,23 @@ bool v4l2_fh_del(struct v4l2_fh *fh);
> */
> void v4l2_fh_exit(struct v4l2_fh *fh);
> /*
> + * It deletes and exits the v4l2_fh associated with the file pointer and
> + * frees it. It will do nothing if filp->private_data (the pointer to the
> + * v4l2_fh struct) is NULL. This function returns true if this was the
> + * last open file handle and false otherwise.
> + */
> +bool v4l2_fh_release_is_last(struct file *filp);
> +/*
> * Can be used as the release() op of v4l2_file_operations.
> * It deletes and exits the v4l2_fh associated with the file pointer and
> * frees it. It will do nothing if filp->private_data (the pointer to the
> * v4l2_fh struct) is NULL. This function always returns 0.
> */
> -int v4l2_fh_release(struct file *filp);
> +static inline int v4l2_fh_release(struct file *filp)
> +{
> + v4l2_fh_release_is_last(filp);
> + return 0;
> +}
> /*
> * Returns true if this filehandle is the only filehandle opened for the
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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