[PATCH net 2/5] net: lan966x: Fix usage of lan966x->mac_lock when entry is added

From: Horatiu Vultur
Date: Thu Jul 14 2022 - 15:37:09 EST

To add an entry to the MAC table, it is required first to setup the
entry and then issue a command for the MAC to learn the entry.
So if it happens for two threads to add simultaneously an entry in MAC
table then it would be a race condition.
Fix this by using lan966x->mac_lock to protect the HW access.

Fixes: fc0c3fe7486f2 ("net: lan966x: Add function lan966x_mac_ip_learn()")
Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
drivers/net/ethernet/microchip/lan966x/lan966x_mac.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 2d2b83c03796..4f8fd5cde950 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -75,6 +75,9 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
unsigned int vid,
enum macaccess_entry_type type)
+ int ret;
+ spin_lock(&lan966x->mac_lock);
lan966x_mac_select(lan966x, mac, vid);

/* Issue a write command */
@@ -86,7 +89,10 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
lan966x, ANA_MACACCESS);

- return lan966x_mac_wait_for_completion(lan966x);
+ ret = lan966x_mac_wait_for_completion(lan966x);
+ spin_unlock(&lan966x->mac_lock);
+ return ret;

/* The mask of the front ports is encoded inside the mac parameter via a call