Merge "USB: f_mtp: Avoid queuing of receive_file_work for 0 length"

	 * in kernel context, which is necessary for vfs_read and

	 * vfs_write to use our buffers in the kernel address space.

	 */

	dev->xfer_result = 0;

	if (dev->xfer_file_length) {

		queue_work(dev->wq, work);

		/* wait for operation to complete */

		flush_workqueue(dev->wq);

	fput(filp);

		/* read the result */

		smp_rmb();

	}

	ret = dev->xfer_result;

	fput(filp);

fail:

	spin_lock_irq(&dev->lock);