6bfbfcfc58
The tty line disciplines don't expect tty_operations::write_room to return negative values. Fix the five drivers which violate this. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210302062214.29627-44-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>