net: dsa: no longer clone skb in core driver

It was a waste to clone skb directly in dsa_skb_tx_timestamp().
For one-step timestamping, a clone was not needed. For any failure of
port_txtstamp (this may usually happen), the skb clone had to be freed.

So this patch moves skb cloning for tx timestamp out of dsa core, and
let drivers clone skb in port_txtstamp if they really need.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Tested-by: Kurt Kanzenbach <kurt@linutronix.de>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c

@@ -373,31 +373,38 @@ long hellcreek_hwtstamp_work(struct ptp_clock_info *ptp)
 	return restart ? 1 : -1;
 }
 
-bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone)
+void hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb)
 {
 	struct hellcreek *hellcreek = ds->priv;
 	struct hellcreek_port_hwtstamp *ps;
 	struct ptp_header *hdr;
+	struct sk_buff *clone;
 	unsigned int type;
 
 	ps = &hellcreek->ports[port].port_hwtstamp;
 
-	type = ptp_classify_raw(clone);
+	type = ptp_classify_raw(skb);
 	if (type == PTP_CLASS_NONE)
-		return false;
+		return;
 
 	/* Make sure the message is a PTP message that needs to be timestamped
 	 * and the interaction with the HW timestamping is enabled. If not, stop
 	 * here
 	 */
-	hdr = hellcreek_should_tstamp(hellcreek, port, clone, type);
+	hdr = hellcreek_should_tstamp(hellcreek, port, skb, type);
 	if (!hdr)
-		return false;
+		return;
+
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
 
 	if (test_and_set_bit_lock(HELLCREEK_HWTSTAMP_TX_IN_PROGRESS,
-				  &ps->state))
-		return false;
+				  &ps->state)) {
+		kfree_skb(clone);
+		return;
+	}
 
 	ps->tx_skb = clone;
 
@@ -407,8 +414,6 @@ bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
 	ps->tx_tstamp_start = jiffies;
 
 	ptp_schedule_worker(hellcreek->ptp_clock, 0);
-
-	return true;
 }
 
 bool hellcreek_port_rxtstamp(struct dsa_switch *ds, int port,

drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h

@@ -44,8 +44,8 @@ int hellcreek_port_hwtstamp_get(struct dsa_switch *ds, int port,
 
 bool hellcreek_port_rxtstamp(struct dsa_switch *ds, int port,
 			     struct sk_buff *clone, unsigned int type);
-bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone);
+void hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb);
 
 int hellcreek_get_ts_info(struct dsa_switch *ds, int port,
 			  struct ethtool_ts_info *info);

drivers/net/dsa/mv88e6xxx/hwtstamp.c

@@ -468,32 +468,38 @@ long mv88e6xxx_hwtstamp_work(struct ptp_clock_info *ptp)
 	return restart ? 1 : -1;
 }
 
-bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone)
+void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
 	struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
 	struct ptp_header *hdr;
+	struct sk_buff *clone;
 	unsigned int type;
 
-	type = ptp_classify_raw(clone);
+	type = ptp_classify_raw(skb);
 	if (type == PTP_CLASS_NONE)
-		return false;
+		return;
 
-	hdr = mv88e6xxx_should_tstamp(chip, port, clone, type);
+	hdr = mv88e6xxx_should_tstamp(chip, port, skb, type);
 	if (!hdr)
-		return false;
+		return;
+
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
 
 	if (test_and_set_bit_lock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS,
-				  &ps->state))
-		return false;
+				  &ps->state)) {
+		kfree_skb(clone);
+		return;
+	}
 
 	ps->tx_skb = clone;
 	ps->tx_tstamp_start = jiffies;
 	ps->tx_seq_id = be16_to_cpu(hdr->sequence_id);
 
 	ptp_schedule_worker(chip->ptp_clock, 0);
-	return true;
 }
 
 int mv88e6165_global_disable(struct mv88e6xxx_chip *chip)

drivers/net/dsa/mv88e6xxx/hwtstamp.h

@@ -117,8 +117,8 @@ int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
 
 bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
 			     struct sk_buff *clone, unsigned int type);
-bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-			     struct sk_buff *clone);
+void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+			     struct sk_buff *skb);
 
 int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,
 			  struct ethtool_ts_info *info);
@@ -151,10 +151,9 @@ static inline bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
 	return false;
 }
 
-static inline bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
-					   struct sk_buff *clone)
+static inline void mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
+					   struct sk_buff *skb)
 {
-	return false;
 }
 
 static inline int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,

drivers/net/dsa/ocelot/felix.c

@@ -1395,18 +1395,21 @@ static bool felix_rxtstamp(struct dsa_switch *ds, int port,
 	return false;
 }
 
-static bool felix_txtstamp(struct dsa_switch *ds, int port,
-			   struct sk_buff *clone)
+static void felix_txtstamp(struct dsa_switch *ds, int port,
+			   struct sk_buff *skb)
 {
 	struct ocelot *ocelot = ds->priv;
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
+	struct sk_buff *clone;
 
 	if (ocelot->ptp && ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
+		clone = skb_clone_sk(skb);
+		if (!clone)
+			return;
+
 		ocelot_port_add_txtstamp_skb(ocelot, port, clone);
-		return true;
+		DSA_SKB_CB(skb)->clone = clone;
 	}
-
-	return false;
 }
 
 static int felix_change_mtu(struct dsa_switch *ds, int port, int new_mtu)

drivers/net/dsa/sja1105/sja1105_ptp.c

@@ -431,19 +431,24 @@ bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
 	return true;
 }
 
-/* Called from dsa_skb_tx_timestamp. This callback is just to make DSA clone
+/* Called from dsa_skb_tx_timestamp. This callback is just to clone
  * the skb and have it available in DSA_SKB_CB in the .port_deferred_xmit
  * callback, where we will timestamp it synchronously.
  */
-bool sja1105_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
+void sja1105_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
 {
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_port *sp = &priv->ports[port];
+	struct sk_buff *clone;
 
 	if (!sp->hwts_tx_en)
-		return false;
+		return;
 
-	return true;
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
+
+	DSA_SKB_CB(skb)->clone = clone;
 }
 
 static int sja1105_ptp_reset(struct dsa_switch *ds)

drivers/net/dsa/sja1105/sja1105_ptp.h

@@ -104,7 +104,7 @@ void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
 bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
 			   struct sk_buff *skb, unsigned int type);
 
-bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
+void sja1105_port_txtstamp(struct dsa_switch *ds, int port,
 			   struct sk_buff *skb);
 
 int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);

include/net/dsa.h

@@ -740,8 +740,8 @@ struct dsa_switch_ops {
 				     struct ifreq *ifr);
 	int	(*port_hwtstamp_set)(struct dsa_switch *ds, int port,
 				     struct ifreq *ifr);
-	bool	(*port_txtstamp)(struct dsa_switch *ds, int port,
-				 struct sk_buff *clone);
+	void	(*port_txtstamp)(struct dsa_switch *ds, int port,
+				 struct sk_buff *skb);
 	bool	(*port_rxtstamp)(struct dsa_switch *ds, int port,
 				 struct sk_buff *skb, unsigned int type);
 

net/dsa/slave.c

@@ -555,7 +555,6 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
 				 struct sk_buff *skb)
 {
 	struct dsa_switch *ds = p->dp->ds;
-	struct sk_buff *clone;
 
 	if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
 		return;
@@ -563,16 +562,7 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
 	if (!ds->ops->port_txtstamp)
 		return;
 
-	clone = skb_clone_sk(skb);
-	if (!clone)
-		return;
-
-	if (ds->ops->port_txtstamp(ds, p->dp->index, clone)) {
-		DSA_SKB_CB(skb)->clone = clone;
-		return;
-	}
-
-	kfree_skb(clone);
+	ds->ops->port_txtstamp(ds, p->dp->index, skb);
 }
 
 netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)