On 04/10/18 13:07, Mauro Carvalho Chehab wrote: > Em Mon, 9 Apr 2018 16:20:04 +0200 > Hans Verkuil <hverkuil@xxxxxxxxx> escreveu: > >> 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); > > Huh? The spin lock were used before only to protect the req->state, > while the mutex is the one that protects the request itself. > > So, here, it should be doing mutex_lock/unlock() instead. The mutex only serializes the actual queuing operation where you queue a request (and will likely have to sleep etc.). The spinlock is for the the other fields of the media_request struct. Regards, Hans > >> + 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. > > @req ? > >> + * >> + * 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; > > > > Thanks, > Mauro >