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author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2020-09-18 04:07:24 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2020-09-18 23:52:33 +0300 |
commit | 6565243c0677aa2befa5a953cf11bc7b4a6f0a47 (patch) | |
tree | 2b57ec438bfe55b8e25f47f4a7df5e7aae959545 /scripts | |
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 'scripts')
0 files changed, 0 insertions, 0 deletions