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net: mscc: ocelot: fix race condition with TX timestamping

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The TX-timestampable skb is added late to the ocelot_port->tx_skbs. It
is in a race with the TX timestamp IRQ, which checks that queue trying
to match the timestamp with the skb by the ts_id. The skb should be
added to the queue before the IRQ can fire.

Fixes: 4e3b0468e6 ("net: mscc: PTP Hardware Clock (PHC) support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2020-09-18 04:07:23 +03:00 committed by David S. Miller
parent 5f6857e808
commit 9dda66acdd
1 changed files with 8 additions and 6 deletions
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14
drivers/net/ethernet/mscc/ocelot_net.c
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@ -330,6 +330,7 @@ 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))) ||
@ -344,10 +345,14 @@ 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)
if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
info.rew_op |= (ocelot_port->ts_id % 4) << 3;
ocelot_port->ts_id++;
}
}
ocelot_gen_ifh(ifh, &info);
@ -380,12 +385,9 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
if (!ocelot_port_add_txtstamp_skb(ocelot_port, skb)) {
ocelot_port->ts_id++;
return NETDEV_TX_OK;
}
if (!do_tstamp)
dev_kfree_skb_any(skb);
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}