caif: set traffic class for caif packets

Set traffic class for CAIF packets, based on socket
priority, CAIF protocol type, or type of message.

Traffic class mapping for different packet types:
 - control:       TC_PRIO_CONTROL;
 - flow control:  TC_PRIO_CONTROL;
 - at:            TC_PRIO_CONTROL;
 - rfm:           TC_PRIO_INTERACTIVE_BULK;
 - other sockets: equals to socket's TC;
 - network data:  no change.

Signed-off-by: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
index e335ba8..863dedd 100644
--- a/net/caif/cfpkt_skbuff.c
+++ b/net/caif/cfpkt_skbuff.c
@@ -381,6 +381,7 @@
 	memcpy(skb2->data, split, len2nd);
 	skb2->tail += len2nd;
 	skb2->len += len2nd;
+	skb2->priority = skb->priority;
 	return skb_to_pkt(skb2);
 }
 
@@ -394,3 +395,9 @@
 	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
 }
 EXPORT_SYMBOL(cfpkt_info);
+
+void cfpkt_set_prio(struct cfpkt *pkt, int prio)
+{
+	pkt_to_skb(pkt)->priority = prio;
+}
+EXPORT_SYMBOL(cfpkt_set_prio);