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From:   Ricardo Ribalda <ribalda@chromium.org>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Ricardo Ribalda <ribalda@chromium.org>
Subject: [PATCH v5 02/12] media: uvcvideo: Allow more that one asyc_ctrl
Date:   Mon, 21 Dec 2020 17:48:09 +0100
Message-Id: <20201221164819.792019-3-ribalda@chromium.org>
In-Reply-To: <20201221164819.792019-1-ribalda@chromium.org>
References: <20201221164819.792019-1-ribalda@chromium.org>
MIME-Version: 1.0
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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(-)

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 {
-- 
2.29.2.684.gfbc64c5ab5-goog