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 <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/caif/cfpkt.h

···
  */
 void *cfpkt_tonative(struct cfpkt *pkt);
 
-
 /*
  * Returns packet information for a packet.
  * pkt Packet to get info from;
  * @return Packet information
  */
 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt);
+
+/** cfpkt_set_prio - set priority for a CAIF packet.
+ *
+ * @pkt: The CAIF packet to be adjusted.
+ * @prio: one of TC_PRIO_ constants.
+ */
+void cfpkt_set_prio(struct cfpkt *pkt, int prio);
+
 #endif				/* CFPKT_H_ */

net/caif/caif_socket.c

···
 #include <linux/uaccess.h>
 #include <linux/debugfs.h>
 #include <linux/caif/caif_socket.h>
-#include <linux/atomic.h>
+#include <linux/pkt_sched.h>
 #include <net/sock.h>
 #include <net/tcp_states.h>
 #include <net/caif/caif_layer.h>
···
 
 	pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 	memset(skb->cb, 0, sizeof(struct caif_payload_info));
+	cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 
 	if (cf_sk->layer.dn == NULL) {
 		kfree_skb(skb);
···
 	/* Store the protocol */
 	sk->sk_protocol = (unsigned char) protocol;
 
+	/* Initialize default priority for well-known cases */
+	switch (protocol) {
+	case CAIFPROTO_AT:
+		sk->sk_priority = TC_PRIO_CONTROL;
+		break;
+	case CAIFPROTO_RFM:
+		sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
+		break;
+	default:
+		sk->sk_priority = TC_PRIO_BESTEFFORT;
+	}
+
 	/*
 	 * Lock in order to try to stop someone from opening the socket
 	 * too early.
···
 	set_rx_flow_on(cf_sk);
 
 	/* Set default options on configuration */
-	cf_sk->sk.sk_priority = CAIF_PRIO_NORMAL;
 	cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
 	cf_sk->conn_req.protocol = protocol;
 	release_sock(&cf_sk->sk);

net/caif/cfctrl.c

···
 #include <linux/stddef.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
+#include <linux/pkt_sched.h>
 #include <net/caif/caif_layer.h>
 #include <net/caif/cfpkt.h>
 #include <net/caif/cfctrl.h>
···
 	cfctrl->serv.dev_info.id = physlinkid;
 	cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
 	cfpkt_addbdy(pkt, physlinkid);
+	cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 	dn->transmit(dn, pkt);
 }
 
···
 	 *	might arrive with the newly allocated channel ID.
 	 */
 	cfpkt_info(pkt)->dev_info->id = param->phyid;
+	cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 	ret =
 	    dn->transmit(dn, pkt);
 	if (ret < 0) {
···
 	cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
 	cfpkt_addbdy(pkt, channelid);
 	init_info(cfpkt_info(pkt), cfctrl);
+	cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 	ret =
 	    dn->transmit(dn, pkt);
 #ifndef CAIF_NO_LOOP

net/caif/cfpkt_skbuff.c

···
 	memcpy(skb2->data, split, len2nd);
 	skb2->tail += len2nd;
 	skb2->len += len2nd;
+	skb2->priority = skb->priority;
 	return skb_to_pkt(skb2);
 }
 
···
 	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);

net/caif/cfsrvl.c

···
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/pkt_sched.h>
 #include <net/caif/caif_layer.h>
 #include <net/caif/cfsrvl.h>
 #include <net/caif/cfpkt.h>
···
 			info->channel_id = service->layer.id;
 			info->hdr_len = 1;
 			info->dev_info = &service->dev_info;
+			cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 			return layr->dn->transmit(layr->dn, pkt);
 		}
 	case CAIF_MODEMCMD_FLOW_OFF_REQ:
···
 			info->channel_id = service->layer.id;
 			info->hdr_len = 1;
 			info->dev_info = &service->dev_info;
+			cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 			return layr->dn->transmit(layr->dn, pkt);
 		}
 	default: