net: lan966x: Fix usage of lan966x->mac_lock when entry is removed

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>

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 4f8fd5c..d0b8eba 100644 (file)
--- 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);