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| author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2020-09-18 04:07:24 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-09-18 23:52:33 +0300 |
| commit | 6565243c0677aa2befa5a953cf11bc7b4a6f0a47 (patch) | |
| tree | 2b57ec438bfe55b8e25f47f4a7df5e7aae959545 /net | |
| parent | 9dda66acddcbcd5c9e94a1292c679738ba999345 (diff) | |
| download | linux-6565243c0677aa2befa5a953cf11bc7b4a6f0a47.tar.xz | |
net: mscc: ocelot: add locking for the port TX timestamp ID
The ocelot_port->ts_id is used to:
(a) populate skb->cb[0] for matching the TX timestamp in the PTP IRQ
with an skb.
(b) populate the REW_OP from the injection header of the ongoing skb.
Only then is ocelot_port->ts_id incremented.
This is a problem because, at least theoretically, another timestampable
skb might use the same ocelot_port->ts_id before that is incremented.
Normally all transmit calls are serialized by the netdev transmit
spinlock, but in this case, ocelot_port_add_txtstamp_skb() is also
called by DSA, which has started declaring the NETIF_F_LLTX feature
since commit 2b86cb829976 ("net: dsa: declare lockless TX feature for
slave ports"). So the logic of using and incrementing the timestamp id
should be atomic per port.
The solution is to use the global ocelot_port->ts_id only while
protected by the associated ocelot_port->ts_id_lock. That's where we
populate skb->cb[0]. Note that for ocelot, ocelot_port_add_txtstamp_skb
is called for the actual skb, but for felix, it is called for the skb's
clone. That is something which will also be changed in the future.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/dsa/tag_ocelot.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c index 42f327c06dca..b4fc05cafaa6 100644 --- a/net/dsa/tag_ocelot.c +++ b/net/dsa/tag_ocelot.c @@ -160,11 +160,14 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb, 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; + rew_op = ocelot_port->ptp_cmd; - if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) { - rew_op |= (ocelot_port->ts_id % 4) << 3; - ocelot_port->ts_id++; - } + /* Retrieve timestamp ID populated inside skb->cb[0] of the + * clone by ocelot_port_add_txtstamp_skb + */ + if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) + rew_op |= clone->cb[0] << 3; packing(injection, &rew_op, 125, 117, OCELOT_TAG_LEN, PACK, 0); } |