On Mon, Apr 9, 2018 at 11:21 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Add media_request_object_find to find a request object inside a
> request based on ops and/or priv values.
> Objects of the same type (vb2 buffer, control handler) will have
> the same ops value. And objects that refer to the same 'parent'
> object (e.g. the v4l2_ctrl_handler that has the current driver
> state) will have the same priv value.
> The caller has to call media_request_object_put() for the returned
> object since this function increments the refcount.
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/media-request.c | 26 ++++++++++++++++++++++++++
> include/media/media-request.h | 25 +++++++++++++++++++++++++
> 2 files changed, 51 insertions(+)
> diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
> index 02b620c81de5..415f7e31019d 100644
> --- a/drivers/media/media-request.c
> +++ b/drivers/media/media-request.c
> @@ -322,6 +322,32 @@ static void media_request_object_release(struct kref
*kref)
> obj->ops->release(obj);
> }
> +struct media_request_object *
> +media_request_object_find(struct media_request *req,
> + const struct media_request_object_ops *ops,
> + void *priv)
> +{
> + struct media_request_object *obj;
> + struct media_request_object *found = NULL;
> + unsigned long flags;
> +
> + if (!ops && !priv)
> + return NULL;
> +
> + spin_lock_irqsave(&req->lock, flags);
> + list_for_each_entry(obj, &req->objects, list) {
> + if ((!ops || obj->ops == ops) &&
> + (!priv || obj->priv == priv)) {
> + media_request_object_get(obj);
> + found = obj;
> + break;
> + }
> + }
> + spin_unlock_irqrestore(&req->lock, flags);
> + return found;
> +}
> +EXPORT_SYMBOL_GPL(media_request_object_find);
> +
> void media_request_object_put(struct media_request_object *obj)
> {
> kref_put(&obj->kref, media_request_object_release);
> diff --git a/include/media/media-request.h b/include/media/media-request.h
> index 033697d493cd..ea990c8f76bc 100644
> --- a/include/media/media-request.h
> +++ b/include/media/media-request.h
> @@ -130,6 +130,23 @@ static inline void media_request_object_get(struct
media_request_object *obj)
> */
> void media_request_object_put(struct media_request_object *obj);
> +/**
> + * media_request_object_find - Find an object in a request
> + *
> + * @ops: Find an object with this ops value, may be NULL.
> + * @priv: Find an object with this priv value, may be NULL.
> + *
> + * At least one of @ops and @priv must be non-NULL. If one of
> + * these is NULL, then skip checking for that field.
> + *
> + * Returns NULL if not found or the object (the refcount is increased
> + * in that case).
> + */
> +struct media_request_object *
> +media_request_object_find(struct media_request *req,
> + const struct media_request_object_ops *ops,
> + void *priv);
Mm, that signature is weird. I don't yet know how this function is going to
be
called, but wouldn't priv be enough? If we look for ops, this means we are
looking for the first object of a given class (IIUC the class/objects
mechanism
here), and I cannot see where we would want to do that.
> +
> /**
> * media_request_object_init - Initialise a media request object
> *
> @@ -162,6 +179,14 @@ static inline void media_request_object_put(struct
media_request_object *obj)
> {
> }
> +static inline struct media_request_object *
> +media_request_object_find(struct media_request *req,
> + const struct media_request_object_ops *ops,
> + void *priv)
> +{
> + return NULL;
> +}
> +
> static inline void media_request_object_init(struct media_request_object
*obj)
> {
> obj->ops = NULL;
> --
> 2.16.3
