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X-CSE-ConnectionGUID: kVvLDWavQbSbaHL4xCrBEA== X-CSE-MsgGUID: YzlEtEPBRL2CRiQZTfjSZQ== X-IronPort-AV: E=McAfee;i="6800,10657,11454"; a="62262541" X-IronPort-AV: E=Sophos;i="6.16,211,1744095600"; d="scan'208";a="62262541" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2025 23:51:07 -0700 X-CSE-ConnectionGUID: xu2tSk4iTv2MRpKjasZFEA== X-CSE-MsgGUID: oJ/ST0IjQoWa8lS+Ksbi+A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,211,1744095600"; d="scan'208";a="150569068" Received: from cpetruta-mobl1.ger.corp.intel.com (HELO kekkonen.fi.intel.com) ([10.245.244.16]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2025 23:51:03 -0700 Received: from kekkonen.localdomain (localhost [127.0.0.1]) by kekkonen.fi.intel.com (Postfix) with ESMTP id 8AECE12023B; Thu, 5 Jun 2025 09:51:00 +0300 (EEST) Date: Thu, 5 Jun 2025 06:51:00 +0000 Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo From: Sakari Ailus To: Nicolas Dufresne Cc: Laurent Pinchart , Mauro Carvalho Chehab , Hans Verkuil , Tiffany Lin , Andrew-CT Chen , Yunfei Dong , Matthias Brugger , AngeloGioacchino Del Regno , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, kernel@collabora.com, linux-media@vger.kernel.org, Sebastian Fricke Subject: Re: [PATCH v3 1/5] media: mc: add manual request completion Message-ID: References: <20250604-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v3-0-603db4749d90@collabora.com> <20250604-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v3-1-603db4749d90@collabora.com> <1ccaaec7f782afc71bae5c3b0f60a786a907555c.camel@collabora.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1ccaaec7f782afc71bae5c3b0f60a786a907555c.camel@collabora.com> Hi Nicolas, On Wed, Jun 04, 2025 at 07:19:27PM -0400, Nicolas Dufresne wrote: > Le mercredi 04 juin 2025 à 21:04 +0000, Sakari Ailus a écrit : > > Hi Nicolas, > > > > Thanks for the update. > > > > On Wed, Jun 04, 2025 at 04:09:35PM -0400, Nicolas Dufresne wrote: > > > From: Hans Verkuil > > > > > > By default when the last request object is completed, the whole > > > request completes as well. > > > > > > But sometimes you want to delay this completion to an arbitrary point in > > > time so add a manual complete mode for this. > > > > > > In req_queue the driver marks the request for manual completion by > > > calling media_request_mark_manual_completion, and when the driver > > > wants to manually complete the request it calls > > > media_request_manual_complete(). > > > > > > Signed-off-by: Hans Verkuil > > > Signed-off-by: Nicolas Dufresne > > > --- > > >  drivers/media/mc/mc-request.c | 38 ++++++++++++++++++++++++++++++++++++-- > > >  include/media/media-request.h | 38 +++++++++++++++++++++++++++++++++++++- > > >  2 files changed, 73 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c > > > index 5edfc2791ce7c7485def5db675bbf53ee223d837..398d0806d1d274eb8c454fc5c37b77476abe1e74 100644 > > > --- a/drivers/media/mc/mc-request.c > > > +++ b/drivers/media/mc/mc-request.c > > > @@ -54,6 +54,7 @@ static void media_request_clean(struct media_request *req) > > >   req->access_count = 0; > > >   WARN_ON(req->num_incomplete_objects); > > >   req->num_incomplete_objects = 0; > > > + req->manual_completion = false; > > >   wake_up_interruptible_all(&req->poll_wait); > > >  } > > >   > > > @@ -313,6 +314,7 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd) > > >   req->mdev = mdev; > > >   req->state = MEDIA_REQUEST_STATE_IDLE; > > >   req->num_incomplete_objects = 0; > > > + req->manual_completion = false; > > >   kref_init(&req->kref); > > >   INIT_LIST_HEAD(&req->objects); > > >   spin_lock_init(&req->lock); > > > @@ -459,7 +461,7 @@ void media_request_object_unbind(struct media_request_object *obj) > > >   > > >   req->num_incomplete_objects--; > > >   if (req->state == MEDIA_REQUEST_STATE_QUEUED && > > > -     !req->num_incomplete_objects) { > > > +     !req->num_incomplete_objects && !req->manual_completion) { > > >   req->state = MEDIA_REQUEST_STATE_COMPLETE; > > >   completed = true; > > >   wake_up_interruptible_all(&req->poll_wait); > > > @@ -488,7 +490,7 @@ void media_request_object_complete(struct media_request_object *obj) > > >       WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED)) > > >   goto unlock; > > >   > > > - if (!--req->num_incomplete_objects) { > > > + if (!--req->num_incomplete_objects && !req->manual_completion) { > > >   req->state = MEDIA_REQUEST_STATE_COMPLETE; > > >   wake_up_interruptible_all(&req->poll_wait); > > >   completed = true; > > > @@ -499,3 +501,35 @@ void media_request_object_complete(struct media_request_object *obj) > > >   media_request_put(req); > > >  } > > >  EXPORT_SYMBOL_GPL(media_request_object_complete); > > > + > > > +void media_request_manual_complete(struct media_request *req) > > > +{ > > > + unsigned long flags; > > > > I'd declare flags as last. > > > > > + bool completed = false; > > > + > > > + if (WARN_ON(!req)) > > > + return; > > > + if (WARN_ON(!req->manual_completion)) > > > + return; > > > > I think I'd use WARN_ON_ONCE() consistently: this is a driver (or > > framework) bug and telling once about it is very probably enough. > > Just to be sure, you only mean for the two checks above ? Or did > you mean for the entire function ? For the entire function. I thought that if this is user-triggerable, the amount of data ending up in logs could be very large. > > > > > > + > > > + spin_lock_irqsave(&req->lock, flags); > > In practice, if you call this specific function from two places at the same > time you have a bug, but I realize that moving the the warning on the check > manual_completion inside that lock would massively help detect that case. > > What do you think ? Seems reasonable to me. > > > > + if (WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED)) > > > + goto unlock; > > > + > > > + req->manual_completion = false; > > > + /* > > > + * It is expected that all other objects in this request are > > > + * completed when this function is called. WARN if that is > > > + * not the case. > > > + */ > > > + if (!WARN_ON(req->num_incomplete_objects)) { > > > + req->state = MEDIA_REQUEST_STATE_COMPLETE; > > > + wake_up_interruptible_all(&req->poll_wait); > > > + completed = true; > > > + } > > > > A newline would be nice here. > > > > > +unlock: > > > + spin_unlock_irqrestore(&req->lock, flags); > > > + if (completed) > > > + media_request_put(req); > > > +} > > > +EXPORT_SYMBOL_GPL(media_request_manual_complete); > > > diff --git a/include/media/media-request.h b/include/media/media-request.h > > > index d4ac557678a78372222704400c8c96cf3150b9d9..7f9af68ef19ac6de0184bbb0c0827dc59777c6dc 100644 > > > --- a/include/media/media-request.h > > > +++ b/include/media/media-request.h > > > @@ -56,6 +56,9 @@ struct media_request_object; > > >   * @access_count: count the number of request accesses that are in progress > > >   * @objects: List of @struct media_request_object request objects > > >   * @num_incomplete_objects: The number of incomplete objects in the request > > > + * @manual_completion: if true, then the request won't be marked as completed > > > + * when @num_incomplete_objects reaches 0. Call media_request_manual_complete() > > > + * to complete the request after @num_incomplete_objects == 0. > > >   * @poll_wait: Wait queue for poll > > >   * @lock: Serializes access to this struct > > >   */ > > > @@ -68,6 +71,7 @@ struct media_request { > > >   unsigned int access_count; > > >   struct list_head objects; > > >   unsigned int num_incomplete_objects; > > > + bool manual_completion; > > >   wait_queue_head_t poll_wait; > > >   spinlock_t lock; > > >  }; > > > @@ -218,6 +222,38 @@ media_request_get_by_fd(struct media_device *mdev, int request_fd); > > >  int media_request_alloc(struct media_device *mdev, > > >   int *alloc_fd); > > >   > > > +/** > > > + * media_request_mark_manual_completion - Enable manual completion > > > + * > > > + * @req: The request > > > + * > > > + * Mark that the request has to be manually completed by calling > > > + * media_request_manual_complete(). > > > + * > > > + * This function shall be called in the req_queue callback. > > > + */ > > > +static inline void > > > +media_request_mark_manual_completion(struct media_request *req) > > > +{ > > > + req->manual_completion = true; > > > +} > > > + > > > +/** > > > + * media_request_manual_complete - Mark the request as completed > > > + * > > > + * @req: The request > > > + * > > > + * This function completes a request that was marked for manual completion by an > > > + * earlier call to media_request_mark_manual_completion(). The request's > > > + * @manual_completion flag is reset to false. > > > > s/flag/field/ > > > > > + * > > > + * All objects contained in the request must have been completed previously. It > > > + * is an error to call this function otherwise. If such an error occurred, the > > > + * function will WARN and the object completion will be delayed until > > > + * @num_incomplete_objects is 0. > > > + */ > > > +void media_request_manual_complete(struct media_request *req); > > > + > > >  #else > > >   > > >  static inline void media_request_get(struct media_request *req) > > > @@ -336,7 +372,7 @@ void media_request_object_init(struct media_request_object *obj); > > >   * @req: The media request > > >   * @ops: The object ops for this object > > >   * @priv: A driver-specific priv pointer associated with this object > > > - * @is_buffer: Set to true if the object a buffer object. > > > + * @is_buffer: Set to true if the object is a buffer object. > > >   * @obj: The object > > >   * > > >   * Bind this object to the request and set the ops and priv values of > > > -- Kind regards, Sakari Ailus