On 04/12/2018 02:23 PM, Sakari Ailus wrote:
> Hi Hans,
>
> On Mon, Apr 09, 2018 at 04:20:04PM +0200, Hans Verkuil 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)) {
>
> I think I may have given the similar comment on an earlier version but I
> don't remember a reply to that at least --- is there a case where the
> object wouldn't be uniquely identified by req together with priv?
>
> It'd be still prudent to check that ops match, but failing that check, I'd
> add WARN_ON() because it's a sign something is wrong.
Currently both ops and priv are always non-NULL, so I've made that the
requirement and call WARN_ON if either is NULL.
Regards,
Hans
>
>> + 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);
>> +
>> /**
>> * 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;
>
