If the FIFO of the card is small, many short messages are queued up to the upper layers and the userspace. This change allows the applications to set a minimum datalen they want from the drivers. Create a common control function to avoid code duplication in each driver. Signed-off-by: Karsten Keil <kkeil@linux-pingi.de> Signed-off-by: David S. Miller <davem@davemloft.net>