[PATCH 5.18 086/158] net: lan966x: Fix usage of lan966x->mac_lock when entry is removed

Greg Kroah-Hartman
2022-07-27T17:37:58Z

From: Horatiu Vultur <horatiu.vultur@microchip.com>

[ Upstream commit 99343cfa4f7560abf933fff7ab3ea58a6905c917 ]

To remove an entry to the MAC table, it is required first to setup the
entry and then issue a command for the MAC to forget the entry.
So if it happens for two threads to remove 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: e18aba8941b40 ("net: lan966x: add mactable support")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../ethernet/microchip/lan966x/lan966x_mac.c | 24 +++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 4f8fd5cde950..d0b8eba0a66d 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -119,11 +119,13 @@ int lan966x_mac_learn(struct lan966x *lan966x, int port,
return __lan966x_mac_learn(lan966x, port, false, mac, vid, type);
}

-int lan966x_mac_forget(struct lan966x *lan966x,
- const unsigned char mac[ETH_ALEN],
- unsigned int vid,
- enum macaccess_entry_type type)
+static int lan966x_mac_forget_locked(struct lan966x *lan966x,
+ const unsigned char mac[ETH_ALEN],
+ unsigned int vid,
+ enum macaccess_entry_type type)
{
+ lockdep_assert_held(&lan966x->mac_lock);
+
lan966x_mac_select(lan966x, mac, vid);

/* Issue a forget command */
@@ -134,6 +136,20 @@ int lan966x_mac_forget(struct lan966x *lan966x,
return lan966x_mac_wait_for_completion(lan966x);
}

+int lan966x_mac_forget(struct lan966x *lan966x,
+ const unsigned char mac[ETH_ALEN],
+ unsigned int vid,
+ enum macaccess_entry_type type)
+{
+ int ret;
+
+ spin_lock(&lan966x->mac_lock);
+ ret = lan966x_mac_forget_locked(lan966x, mac, vid, type);
+ spin_unlock(&lan966x->mac_lock);
+
+ return ret;
+}
+
int lan966x_mac_cpu_learn(struct lan966x *lan966x, const char *addr, u16 vid)
{
return lan966x_mac_learn(lan966x, PGID_CPU, addr, vid, ENTRYTYPE_LOCKED);
--
2.35.1