With the inital implementation we missed to implement a skb backlog
queue . The result is that socket receive processing tossed packets.
Since AF_IUCV connections are working synchronously it leads to
connection hangs. Problems with read, close and select also occured.

Using a skb backlog queue is fixing all of these problems .
Signed-off-by: NJennifer Hunt <jenhunt@us.ibm.com>
Signed-off-by: NFrank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Jennifer Hunt <jenhunt@us.ibm.com>

This patch adds AF_IUCV socket support.
Signed-off-by: NFrank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>