media: switch to fdget()

struct media_request *

media_request_get_by_fd(struct media_device *mdev, int request_fd)

{

	struct file *filp;

	struct fd f;

	struct media_request *req;

	if (!mdev || !mdev->ops ||

	    !mdev->ops->req_validate || !mdev->ops->req_queue)

		return ERR_PTR(-EACCES);

	filp = fget(request_fd);

	if (!filp)

	f = fdget(request_fd);

	if (!f.file)

		goto err_no_req_fd;

	if (filp->f_op != &request_fops)

	if (f.file->f_op != &request_fops)

		goto err_fput;

	req = filp->private_data;

	req = f.file->private_data;

	if (req->mdev != mdev)

		goto err_fput;

	/*

	 * Note: as long as someone has an open filehandle of the request,

	 * the request can never be released. The fget() above ensures that

	 * the request can never be released. The fdget() above ensures that

	 * even if userspace closes the request filehandle, the release()

	 * fop won't be called, so the media_request_get() always succeeds

	 * and there is no race condition where the request was released

	 * before media_request_get() is called.

	 */

	media_request_get(req);

	fput(filp);

	fdput(f);

	return req;

err_fput:

	fput(filp);

	fdput(f);

err_no_req_fd:

	dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);