[PATCH 5.18 088/158] net: lan966x: Fix usage of lan966x->mac_lock when used by FDB

Greg Kroah-Hartman
2022-07-27T17:39:01Z

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

[ Upstream commit 675c807ae26b267233b97cd5006979a6bb8d54d4 ]

When the SW bridge was trying to add/remove entries to/from HW, the
access to HW was not protected by any lock. In this way, it was
possible to have race conditions.
Fix this by using the lan966x->mac_lock to protect parallel access to HW
for this cases.

Fixes: 25ee9561ec622 ("net: lan966x: More MAC table functionality")
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 | 34 +++++++++++++------
1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 69e343b7f4af..5893770bfd94 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -201,7 +201,6 @@ static struct lan966x_mac_entry *lan966x_mac_find_entry(struct lan966x *lan966x,
struct lan966x_mac_entry *res = NULL;
struct lan966x_mac_entry *mac_entry;

- spin_lock(&lan966x->mac_lock);
list_for_each_entry(mac_entry, &lan966x->mac_entries, list) {
if (mac_entry->vid == vid &&
ether_addr_equal(mac, mac_entry->mac) &&
@@ -210,7 +209,6 @@ static struct lan966x_mac_entry *lan966x_mac_find_entry(struct lan966x *lan966x,
break;
}
}
- spin_unlock(&lan966x->mac_lock);

return res;
}
@@ -253,8 +251,11 @@ int lan966x_mac_add_entry(struct lan966x *lan966x, struct lan966x_port *port,
{
struct lan966x_mac_entry *mac_entry;

- if (lan966x_mac_lookup(lan966x, addr, vid, ENTRYTYPE_NORMAL))
+ spin_lock(&lan966x->mac_lock);
+ if (lan966x_mac_lookup(lan966x, addr, vid, ENTRYTYPE_NORMAL)) {
+ spin_unlock(&lan966x->mac_lock);
return 0;
+ }

/* In case the entry already exists, don't add it again to SW,
* just update HW, but we need to look in the actual HW because
@@ -263,21 +264,25 @@ int lan966x_mac_add_entry(struct lan966x *lan966x, struct lan966x_port *port,
* add the entry but without the extern_learn flag.
*/
mac_entry = lan966x_mac_find_entry(lan966x, addr, vid, port->chip_port);
- if (mac_entry)
- return lan966x_mac_learn(lan966x, port->chip_port,
- addr, vid, ENTRYTYPE_LOCKED);
+ if (mac_entry) {
+ spin_unlock(&lan966x->mac_lock);
+ goto mac_learn;
+ }

mac_entry = lan966x_mac_alloc_entry(addr, vid, port->chip_port);
- if (!mac_entry)
+ if (!mac_entry) {
+ spin_unlock(&lan966x->mac_lock);
return -ENOMEM;
+ }

- spin_lock(&lan966x->mac_lock);
list_add_tail(&mac_entry->list, &lan966x->mac_entries);
spin_unlock(&lan966x->mac_lock);

- lan966x_mac_learn(lan966x, port->chip_port, addr, vid, ENTRYTYPE_LOCKED);
lan966x_fdb_call_notifiers(SWITCHDEV_FDB_OFFLOADED, addr, vid, port->dev);

+mac_learn:
+ lan966x_mac_learn(lan966x, port->chip_port, addr, vid, ENTRYTYPE_LOCKED);
+
return 0;
}

@@ -291,8 +296,9 @@ int lan966x_mac_del_entry(struct lan966x *lan966x, const unsigned char *addr,
list) {
if (mac_entry->vid == vid &&
ether_addr_equal(addr, mac_entry->mac)) {
- lan966x_mac_forget(lan966x, mac_entry->mac, mac_entry->vid,
- ENTRYTYPE_LOCKED);
+ lan966x_mac_forget_locked(lan966x, mac_entry->mac,
+ mac_entry->vid,
+ ENTRYTYPE_LOCKED);

list_del(&mac_entry->list);
kfree(mac_entry);
@@ -428,6 +434,12 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
continue;

spin_lock(&lan966x->mac_lock);
+ mac_entry = lan966x_mac_find_entry(lan966x, mac, vid, dest_idx);
+ if (mac_entry) {
+ spin_unlock(&lan966x->mac_lock);
+ continue;
+ }
+
mac_entry = lan966x_mac_alloc_entry(mac, vid, dest_idx);
if (!mac_entry) {
spin_unlock(&lan966x->mac_lock);
--
2.35.1