net: mscc: ocelot: always pass skb clone to ocelot_port_add_txtstamp_skb

Currently, ocelot switchdev passes the skb directly to the function that
enqueues it to the list of skb's awaiting a TX timestamp. Whereas the
felix DSA driver first clones the skb, then passes the clone to this
queue.

This matters because in the case of felix, the common IRQ handler, which
is ocelot_get_txtstamp(), currently clones the clone, and frees the
original clone. This is useless and can be simplified by using
skb_complete_tx_timestamp() instead of skb_tstamp_tx().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/ocelot/felix.c

@@ -669,8 +669,11 @@ static bool felix_txtstamp(struct dsa_switch *ds, int port,
 	struct ocelot *ocelot = ds->priv;
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
 
-	if (!ocelot_port_add_txtstamp_skb(ocelot_port, clone))
+	if (ocelot->ptp && (skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP) &&
+	    ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
+		ocelot_port_add_txtstamp_skb(ocelot, port, clone);
 		return true;
+	}
 
 	return false;
 }

drivers/net/ethernet/mscc/ocelot.c

@@ -413,26 +413,20 @@ void ocelot_port_disable(struct ocelot *ocelot, int port)
 }
 EXPORT_SYMBOL(ocelot_port_disable);
 
-int ocelot_port_add_txtstamp_skb(struct ocelot_port *ocelot_port,
-				 struct sk_buff *skb)
+void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
+				  struct sk_buff *clone)
 {
-	struct skb_shared_info *shinfo = skb_shinfo(skb);
-	struct ocelot *ocelot = ocelot_port->ocelot;
+	struct ocelot_port *ocelot_port = ocelot->ports[port];
 
-	if (ocelot->ptp && shinfo->tx_flags & SKBTX_HW_TSTAMP &&
-	    ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
-		spin_lock(&ocelot_port->ts_id_lock);
+	spin_lock(&ocelot_port->ts_id_lock);
 
-		shinfo->tx_flags |= SKBTX_IN_PROGRESS;
-		/* Store timestamp ID in cb[0] of sk_buff */
-		skb->cb[0] = ocelot_port->ts_id;
-		ocelot_port->ts_id = (ocelot_port->ts_id + 1) % 4;
-		skb_queue_tail(&ocelot_port->tx_skbs, skb);
+	skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;
+	/* Store timestamp ID in cb[0] of sk_buff */
+	clone->cb[0] = ocelot_port->ts_id;
+	ocelot_port->ts_id = (ocelot_port->ts_id + 1) % 4;
+	skb_queue_tail(&ocelot_port->tx_skbs, clone);
 
-		spin_unlock(&ocelot_port->ts_id_lock);
-		return 0;
-	}
-	return -ENODATA;
+	spin_unlock(&ocelot_port->ts_id_lock);
 }
 EXPORT_SYMBOL(ocelot_port_add_txtstamp_skb);
 
@@ -511,9 +505,7 @@ void ocelot_get_txtstamp(struct ocelot *ocelot)
 		/* Set the timestamp into the skb */
 		memset(&shhwtstamps, 0, sizeof(shhwtstamps));
 		shhwtstamps.hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
-		skb_tstamp_tx(skb_match, &shhwtstamps);
-
-		dev_kfree_skb_any(skb_match);
+		skb_complete_tx_timestamp(skb_match, &shhwtstamps);
 
 		/* Next ts */
 		ocelot_write(ocelot, SYS_PTP_NXT_PTP_NXT, SYS_PTP_NXT);

drivers/net/ethernet/mscc/ocelot_net.c

@@ -330,7 +330,6 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 	u8 grp = 0; /* Send everything on CPU group 0 */
 	unsigned int i, count, last;
 	int port = priv->chip_port;
-	bool do_tstamp;
 
 	val = ocelot_read(ocelot, QS_INJ_STATUS);
 	if (!(val & QS_INJ_STATUS_FIFO_RDY(BIT(grp))) ||
@@ -345,7 +344,23 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 	info.vid = skb_vlan_tag_get(skb);
 
 	/* Check if timestamping is needed */
-	do_tstamp = (ocelot_port_add_txtstamp_skb(ocelot_port, skb) == 0);
+	if (ocelot->ptp && (shinfo->tx_flags & SKBTX_HW_TSTAMP)) {
+		info.rew_op = ocelot_port->ptp_cmd;
+
+		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
+			struct sk_buff *clone;
+
+			clone = skb_clone_sk(skb);
+			if (!clone) {
+				kfree_skb(skb);
+				return NETDEV_TX_OK;
+			}
+
+			ocelot_port_add_txtstamp_skb(ocelot, port, clone);
+
+			info.rew_op |= clone->cb[0] << 3;
+		}
+	}
 
 	if (ocelot->ptp && shinfo->tx_flags & SKBTX_HW_TSTAMP) {
 		info.rew_op = ocelot_port->ptp_cmd;
@@ -383,8 +398,7 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;
 
-	if (!do_tstamp)
-		dev_kfree_skb_any(skb);
+	kfree_skb(skb);
 
 	return NETDEV_TX_OK;
 }

include/soc/mscc/ocelot.h

@@ -710,8 +710,8 @@ int ocelot_vlan_add(struct ocelot *ocelot, int port, u16 vid, bool pvid,
 int ocelot_vlan_del(struct ocelot *ocelot, int port, u16 vid);
 int ocelot_hwstamp_get(struct ocelot *ocelot, int port, struct ifreq *ifr);
 int ocelot_hwstamp_set(struct ocelot *ocelot, int port, struct ifreq *ifr);
-int ocelot_port_add_txtstamp_skb(struct ocelot_port *ocelot_port,
-				 struct sk_buff *skb);
+void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,
+				  struct sk_buff *clone);
 void ocelot_get_txtstamp(struct ocelot *ocelot);
 void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu);
 int ocelot_get_max_mtu(struct ocelot *ocelot, int port);

net/dsa/tag_ocelot.c

@@ -137,6 +137,7 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 				   struct net_device *netdev)
 {
 	struct dsa_port *dp = dsa_slave_to_port(netdev);
+	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
 	struct dsa_switch *ds = dp->ds;
 	struct ocelot *ocelot = ds->priv;
 	struct ocelot_port *ocelot_port;
@@ -159,9 +160,8 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	qos_class = skb->priority;
 	packing(injection, &qos_class, 19,  17, OCELOT_TAG_LEN, PACK, 0);
 
-	if (ocelot->ptp && (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
-		struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
-
+	/* TX timestamping was requested */
+	if (clone) {
 		rew_op = ocelot_port->ptp_cmd;
 		/* Retrieve timestamp ID populated inside skb->cb[0] of the
 		 * clone by ocelot_port_add_txtstamp_skb