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 <m.grzeschik@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/arcnet/arcdevice.h

@@ -269,6 +269,10 @@ struct arcnet_local {
 
 	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

@@ -51,6 +51,7 @@
 #include <net/arp.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
+#include <linux/errqueue.h>
 
 #include <linux/leds.h>
 
@@ -391,6 +392,52 @@ static void arcnet_timer(unsigned long data)
 	}
 }
 
+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;
@@ -401,6 +448,7 @@ struct net_device *alloc_arcdev(const char *name)
 	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;
@@ -436,6 +484,9 @@ int arcnet_open(struct net_device *dev)
 		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");
 
 	/* try to put the card in a defined state - if it fails the first
@@ -527,6 +578,8 @@ int arcnet_close(struct net_device *dev)
 	netif_stop_queue(dev);
 	netif_carrier_off(dev);
 
+	tasklet_kill(&lp->reply_tasklet);
+
 	/* flush TX and disable RX */
 	lp->hw.intmask(dev, 0);
 	lp->hw.command(dev, NOTXcmd);	/* stop transmit */
@@ -635,13 +688,13 @@ netdev_tx_t arcnet_send_packet(struct sk_buff *skb,
 		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;
@@ -842,8 +895,16 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 
 		/* 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);
 
@@ -866,18 +927,11 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 
 				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);