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authorVladimir Oltean <vladimir.oltean@nxp.com>2020-09-18 04:07:24 +0300
committerDavid S. Miller <davem@davemloft.net>2020-09-18 13:52:33 -0700
commit6565243c0677aa2befa5a953cf11bc7b4a6f0a47 (patch)
tree2b57ec438bfe55b8e25f47f4a7df5e7aae959545 /include
parent9dda66acddcbcd5c9e94a1292c679738ba999345 (diff)
downloadlinux-6565243c0677aa2befa5a953cf11bc7b4a6f0a47.tar.bz2
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 'include')
-rw-r--r--include/soc/mscc/ocelot.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index da369b12005f..4521dd602ddc 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -566,6 +566,7 @@ struct ocelot_port {
u8 ptp_cmd;
struct sk_buff_head tx_skbs;
u8 ts_id;
+ spinlock_t ts_id_lock;
phy_interface_t phy_mode;