[media] uvcvideo: Return all buffers to vb2 at stream stop and start failure

videobuf2 requires drivers to give back ownership of all queue buffers
in the stop_streaming operation, as well as in the start_streaming
operation in case of failure. Mark all queued buffers as done in the
error or queued state.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index c295c5c..cc96072 100644 (file)
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -42,6 +42,28 @@ uvc_queue_to_stream(struct uvc_video_queue *queue)
        return container_of(queue, struct uvc_streaming, queue);
 }
 
+/*
+ * Return all queued buffers to videobuf2 in the requested state.
+ *
+ * This function must be called with the queue spinlock held.
+ */
+static void uvc_queue_return_buffers(struct uvc_video_queue *queue,
+                              enum uvc_buffer_state state)
+{
+       enum vb2_buffer_state vb2_state = state == UVC_BUF_STATE_ERROR
+                                       ? VB2_BUF_STATE_ERROR
+                                       : VB2_BUF_STATE_QUEUED;
+
+       while (!list_empty(&queue->irqqueue)) {
+               struct uvc_buffer *buf = list_first_entry(&queue->irqqueue,
+                                                         struct uvc_buffer,
+                                                         queue);
+               list_del(&buf->queue);
+               buf->state = state;
+               vb2_buffer_done(&buf->buf, vb2_state);
+       }
+}
+
 /* -----------------------------------------------------------------------------
  * videobuf2 queue operations
  */
@@ -139,10 +161,20 @@ static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
 {
        struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
        struct uvc_streaming *stream = uvc_queue_to_stream(queue);
+       unsigned long flags;
+       int ret;
 
        queue->buf_used = 0;
 
-       return uvc_video_enable(stream, 1);
+       ret = uvc_video_enable(stream, 1);
+       if (ret == 0)
+               return 0;
+
+       spin_lock_irqsave(&queue->irqlock, flags);
+       uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
+       spin_unlock_irqrestore(&queue->irqlock, flags);
+
+       return ret;
 }
 
 static void uvc_stop_streaming(struct vb2_queue *vq)
@@ -154,7 +186,7 @@ static void uvc_stop_streaming(struct vb2_queue *vq)
        uvc_video_enable(stream, 0);
 
        spin_lock_irqsave(&queue->irqlock, flags);
-       INIT_LIST_HEAD(&queue->irqqueue);
+       uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
        spin_unlock_irqrestore(&queue->irqlock, flags);
 }
 
@@ -353,17 +385,10 @@ int uvc_queue_allocated(struct uvc_video_queue *queue)
  */
 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 {
-       struct uvc_buffer *buf;
        unsigned long flags;
 
        spin_lock_irqsave(&queue->irqlock, flags);
-       while (!list_empty(&queue->irqqueue)) {
-               buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
-                                      queue);
-               list_del(&buf->queue);
-               buf->state = UVC_BUF_STATE_ERROR;
-               vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
-       }
+       uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
        /* This must be protected by the irqlock spinlock to avoid race
         * conditions between uvc_buffer_queue and the disconnection event that
         * could result in an interruptible wait in uvc_dequeue_buffer. Do not