net: lan966x: Fix usage of lan966x->mac_lock when used by FDB

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>

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 69e343b..5893770 100644 (file)
--- 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);