+static int frame_ready_nolock(struct gspca_dev *gspca_dev, struct file *file,
+ enum v4l2_memory memory)
+{
+ if (!gspca_dev->present)
+ return -ENODEV;
+ if (gspca_dev->capt_file != file || gspca_dev->memory != memory ||
+ !gspca_dev->streaming)
+ return -EINVAL;
+
+ /* check if a frame is ready */
+ return gspca_dev->fr_o != atomic_read(&gspca_dev->fr_i);
+}
+
+static int frame_ready(struct gspca_dev *gspca_dev, struct file *file,
+ enum v4l2_memory memory)
+{
+ int ret;
+
+ if (mutex_lock_interruptible(&gspca_dev->queue_lock))
+ return -ERESTARTSYS;
+ ret = frame_ready_nolock(gspca_dev, file, memory);
+ mutex_unlock(&gspca_dev->queue_lock);
+ return ret;
+}
+