[v5,02/12] media: uvcvideo: Allow more that one asyc_ctrl

The current implementation allocates memory for only one async_control.
If we get a second event before we have processed the previous one, the
old one gets lost.

Introduce a dynamic memory allocation and a list to handle the
async_controls.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 49 ++++++++++++++++++++++++++------
 drivers/media/usb/uvc/uvcvideo.h | 19 ++++++++-----
 2 files changed, 52 insertions(+), 16 deletions(-)

Hi Ricardo,

Thank you for the patch.

On Mon, Dec 21, 2020 at 05:48:09PM +0100, Ricardo Ribalda wrote:
> The current implementation allocates memory for only one async_control.

> If we get a second event before we have processed the previous one, the

> old one gets lost.

> 

> Introduce a dynamic memory allocation and a list to handle the

> async_controls.


Thinking some more about this, do we need to go through the work queue
at all for GPIO-based events ? Could the part of
uvc_ctrl_status_event_work() before the URB resubmission be moved to
another function, which would be called directly by the GPIO threaded
IRQ handler ?

> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

> ---

>  drivers/media/usb/uvc/uvc_ctrl.c | 49 ++++++++++++++++++++++++++------

>  drivers/media/usb/uvc/uvcvideo.h | 19 ++++++++-----

>  2 files changed, 52 insertions(+), 16 deletions(-)

> 

> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c

> index aa18dcdf8165..69b2fc6ce12c 100644

> --- a/drivers/media/usb/uvc/uvc_ctrl.c

> +++ b/drivers/media/usb/uvc/uvc_ctrl.c

> @@ -1275,11 +1275,9 @@ static void uvc_ctrl_send_slave_event(struct uvc_video_chain *chain,

>  	uvc_ctrl_send_event(chain, handle, ctrl, mapping, val, changes);

>  }

>  

> -static void uvc_ctrl_status_event_work(struct work_struct *work)

> +static void __uvc_ctrl_status_event_work(struct uvc_device *dev,

> +					 struct uvc_ctrl_work *w)

>  {

> -	struct uvc_device *dev = container_of(work, struct uvc_device,

> -					      async_ctrl.work);

> -	struct uvc_ctrl_work *w = &dev->async_ctrl;

>  	struct uvc_video_chain *chain = w->chain;

>  	struct uvc_control_mapping *mapping;

>  	struct uvc_control *ctrl = w->ctrl;

> @@ -1321,23 +1319,54 @@ static void uvc_ctrl_status_event_work(struct work_struct *work)

>  			   ret);

>  }

>  

> +static void uvc_ctrl_status_event_work(struct work_struct *work)

> +{

> +	struct uvc_device *dev = container_of(work, struct uvc_device,

> +					      async_ctrl_work);

> +	struct uvc_ctrl_work *w;

> +

> +	do {

> +		mutex_lock(&dev->async_ctrl_lock);

> +		w = list_first_entry_or_null(&dev->async_ctrl_list,

> +					     struct uvc_ctrl_work,

> +					     list);

> +		if (w)

> +			list_del(&w->list);

> +		mutex_unlock(&dev->async_ctrl_lock);

> +

> +		if (!w)

> +			return;

> +

> +		__uvc_ctrl_status_event_work(dev, w);

> +		kfree(w);

> +	} while (w);

> +}

> +

>  bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain,

>  			   struct uvc_control *ctrl, const u8 *data)

>  {

>  	struct uvc_device *dev = chain->dev;

> -	struct uvc_ctrl_work *w = &dev->async_ctrl;

> +	struct uvc_ctrl_work *w;

>  

>  	if (list_empty(&ctrl->info.mappings)) {

>  		ctrl->handle = NULL;

>  		return false;

>  	}

>  

> +	w = kzalloc(sizeof(*w), GFP_KERNEL);

> +	if (WARN(!w, "Not enough memory to trigger uvc event"))

> +		return false;

> +

>  	memcpy(w->data, data, ctrl->info.size);

>  	w->urb = urb;

>  	w->chain = chain;

>  	w->ctrl = ctrl;

>  

> -	schedule_work(&w->work);

> +	mutex_lock(&dev->async_ctrl_lock);

> +	list_add_tail(&w->list, &dev->async_ctrl_list);

> +	mutex_unlock(&dev->async_ctrl_lock);

> +

> +	schedule_work(&dev->async_ctrl_work);

>  

>  	return true;

>  }

> @@ -2277,7 +2306,9 @@ int uvc_ctrl_init_device(struct uvc_device *dev)

>  	struct uvc_entity *entity;

>  	unsigned int i;

>  

> -	INIT_WORK(&dev->async_ctrl.work, uvc_ctrl_status_event_work);

> +	INIT_WORK(&dev->async_ctrl_work, uvc_ctrl_status_event_work);

> +	mutex_init(&dev->async_ctrl_lock);

> +	INIT_LIST_HEAD(&dev->async_ctrl_list);

>  

>  	/* Walk the entities list and instantiate controls */

>  	list_for_each_entry(entity, &dev->entities, list) {

> @@ -2348,8 +2379,8 @@ void uvc_ctrl_cleanup_device(struct uvc_device *dev)

>  	unsigned int i;

>  

>  	/* Can be uninitialized if we are aborting on probe error. */

> -	if (dev->async_ctrl.work.func)

> -		cancel_work_sync(&dev->async_ctrl.work);

> +	if (dev->async_ctrl_work.func)

> +		cancel_work_sync(&dev->async_ctrl_work);

>  

>  	/* Free controls and control mappings for all entities. */

>  	list_for_each_entry(entity, &dev->entities, list) {

> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h

> index 0db6c2e0bd98..afcaf49fad1a 100644

> --- a/drivers/media/usb/uvc/uvcvideo.h

> +++ b/drivers/media/usb/uvc/uvcvideo.h

> @@ -637,6 +637,14 @@ struct uvc_device_info {

>  	u32	meta_format;

>  };

>  

> +struct uvc_ctrl_work {

> +	struct list_head list;

> +	struct urb *urb;

> +	struct uvc_video_chain *chain;

> +	struct uvc_control *ctrl;

> +	u8 data[UVC_MAX_STATUS_SIZE];

> +};

> +

>  struct uvc_device {

>  	struct usb_device *udev;

>  	struct usb_interface *intf;

> @@ -673,13 +681,10 @@ struct uvc_device {

>  	struct input_dev *input;

>  	char input_phys[64];

>  

> -	struct uvc_ctrl_work {

> -		struct work_struct work;

> -		struct urb *urb;

> -		struct uvc_video_chain *chain;

> -		struct uvc_control *ctrl;

> -		u8 data[UVC_MAX_STATUS_SIZE];

> -	} async_ctrl;

> +	/* Async control */

> +	struct work_struct async_ctrl_work;

> +	struct list_head async_ctrl_list;

> +	struct mutex async_ctrl_lock;

>  };

>  

>  enum uvc_handle_state {


-- 
Regards,

Laurent Pinchart