arcnet: add err_skb package for package status feedback

We need to track the status of our queued packages. This way the driving
process knows if failed packages need to be retransmitted. For this
purpose we queue the transferred/failed packages back into the err_skb
message queue added with some status information.

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

drivers/net/arcnet/arcdevice.h

···
 
 	struct timer_list	timer;
 
+	struct net_device *dev;
+	int reply_status;
+	struct tasklet_struct reply_tasklet;
+
 	/*
 	 * Buffer management: an ARCnet card has 4 x 512-byte buffers, each of
 	 * which can be used for either sending or receiving.  The new dynamic

drivers/net/arcnet/arcnet.c

···
 #include <net/arp.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
+#include <linux/errqueue.h>
 
 #include <linux/leds.h>
 
···
 	}
 }
 
+static void arcnet_reply_tasklet(unsigned long data)
+{
+	struct arcnet_local *lp = (struct arcnet_local *)data;
+
+	struct sk_buff *ackskb, *skb;
+	struct sock_exterr_skb *serr;
+	struct sock *sk;
+	int ret;
+
+	local_irq_disable();
+	skb = lp->outgoing.skb;
+	if (!skb || !skb->sk) {
+		local_irq_enable();
+		return;
+	}
+
+	sock_hold(skb->sk);
+	sk = skb->sk;
+	ackskb = skb_clone_sk(skb);
+	sock_put(skb->sk);
+
+	if (!ackskb) {
+		local_irq_enable();
+		return;
+	}
+
+	serr = SKB_EXT_ERR(ackskb);
+	memset(serr, 0, sizeof(*serr));
+	serr->ee.ee_errno = ENOMSG;
+	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
+	serr->ee.ee_data = skb_shinfo(skb)->tskey;
+	serr->ee.ee_info = lp->reply_status;
+
+	/* finally erasing outgoing skb */
+	dev_kfree_skb(lp->outgoing.skb);
+	lp->outgoing.skb = NULL;
+
+	ackskb->dev = lp->dev;
+
+	ret = sock_queue_err_skb(sk, ackskb);
+	if (ret)
+		kfree_skb(ackskb);
+
+	local_irq_enable();
+};
+
 struct net_device *alloc_arcdev(const char *name)
 {
 	struct net_device *dev;
···
 	if (dev) {
 		struct arcnet_local *lp = netdev_priv(dev);
 
+		lp->dev = dev;
 		spin_lock_init(&lp->lock);
 		init_timer(&lp->timer);
 		lp->timer.data = (unsigned long) dev;
···
 			arc_cont(D_PROTO, "%c", arc_proto_map[count]->suffix);
 		arc_cont(D_PROTO, "\n");
 	}
+
+	tasklet_init(&lp->reply_tasklet, arcnet_reply_tasklet,
+		     (unsigned long)lp);
 
 	arc_printk(D_INIT, dev, "arcnet_open: resetting card.\n");
 
···
 
 	netif_stop_queue(dev);
 	netif_carrier_off(dev);
+
+	tasklet_kill(&lp->reply_tasklet);
 
 	/* flush TX and disable RX */
 	lp->hw.intmask(dev, 0);
···
 		txbuf = -1;
 
 	if (txbuf != -1) {
+		lp->outgoing.skb = skb;
 		if (proto->prepare_tx(dev, pkt, skb->len, txbuf) &&
 		    !proto->ack_tx) {
 			/* done right away and we don't want to acknowledge
 			 *  the package later - forget about it now
 			 */
 			dev->stats.tx_bytes += skb->len;
-			dev_kfree_skb(skb);
 		} else {
 			/* do it the 'split' way */
 			lp->outgoing.proto = proto;
···
 
 		/* a transmit finished, and we're interested in it. */
 		if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {
+			int ackstatus;
 			lp->intmask &= ~(TXFREEflag | EXCNAKflag);
+
+			if (status & TXACKflag)
+				ackstatus = 2;
+			else if (lp->excnak_pending)
+				ackstatus = 1;
+			else
+				ackstatus = 0;
 
 			arc_printk(D_DURING, dev, "TX IRQ (stat=%Xh)\n",
 				   status);
···
 
 				if (lp->outgoing.proto &&
 				    lp->outgoing.proto->ack_tx) {
-					int ackstatus;
-
-					if (status & TXACKflag)
-						ackstatus = 2;
-					else if (lp->excnak_pending)
-						ackstatus = 1;
-					else
-						ackstatus = 0;
-
 					lp->outgoing.proto
 						->ack_tx(dev, ackstatus);
 				}
+				lp->reply_status = ackstatus;
+				tasklet_hi_schedule(&lp->reply_tasklet);
 			}
 			if (lp->cur_tx != -1)
 				release_arcbuf(dev, lp->cur_tx);