mlxsw: spectrum: Fix incorrect reuse of MID entries

In the device, a MID entry represents a group of local ports, which can
later be bound to a MDB entry.

The lookup of an existing MID entry is currently done using the provided
MC MAC address and VID, from the Linux bridge. However, this can result
in an incorrect reuse of the same MID index in different VLAN-unaware
bridges (same IP MC group and VID 0).

Fix this by performing the lookup based on FID instead of VID, which is
unique across different bridges.

Fixes: 3a49b4fd ("mlxsw: Adding layer 2 multicast support")
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NElad Raz <eladr@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -115,7 +115,7 @@ struct mlxsw_sp_rif {
 struct mlxsw_sp_mid {
 	struct list_head list;
 	unsigned char addr[ETH_ALEN];
-	u16 vid;
+	u16 fid;
 	u16 mid;
 	unsigned int ref_count;
 };

drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c

@@ -929,12 +929,12 @@ static int mlxsw_sp_port_smid_set(struct mlxsw_sp_port *mlxsw_sp_port, u16 mid,
 
 static struct mlxsw_sp_mid *__mlxsw_sp_mc_get(struct mlxsw_sp *mlxsw_sp,
 					      const unsigned char *addr,
-					      u16 vid)
+					      u16 fid)
 {
 	struct mlxsw_sp_mid *mid;
 
 	list_for_each_entry(mid, &mlxsw_sp->br_mids.list, list) {
-		if (ether_addr_equal(mid->addr, addr) && mid->vid == vid)
+		if (ether_addr_equal(mid->addr, addr) && mid->fid == fid)
 			return mid;
 	}
 	return NULL;
@@ -942,7 +942,7 @@ static struct mlxsw_sp_mid *__mlxsw_sp_mc_get(struct mlxsw_sp *mlxsw_sp,
 
 static struct mlxsw_sp_mid *__mlxsw_sp_mc_alloc(struct mlxsw_sp *mlxsw_sp,
 						const unsigned char *addr,
-						u16 vid)
+						u16 fid)
 {
 	struct mlxsw_sp_mid *mid;
 	u16 mid_idx;
@@ -958,7 +958,7 @@ static struct mlxsw_sp_mid *__mlxsw_sp_mc_alloc(struct mlxsw_sp *mlxsw_sp,
 
 	set_bit(mid_idx, mlxsw_sp->br_mids.mapped);
 	ether_addr_copy(mid->addr, addr);
-	mid->vid = vid;
+	mid->fid = fid;
 	mid->mid = mid_idx;
 	mid->ref_count = 0;
 	list_add_tail(&mid->list, &mlxsw_sp->br_mids.list);
@@ -991,9 +991,9 @@ static int mlxsw_sp_port_mdb_add(struct mlxsw_sp_port *mlxsw_sp_port,
 	if (switchdev_trans_ph_prepare(trans))
 		return 0;
 
-	mid = __mlxsw_sp_mc_get(mlxsw_sp, mdb->addr, mdb->vid);
+	mid = __mlxsw_sp_mc_get(mlxsw_sp, mdb->addr, fid);
 	if (!mid) {
-		mid = __mlxsw_sp_mc_alloc(mlxsw_sp, mdb->addr, mdb->vid);
+		mid = __mlxsw_sp_mc_alloc(mlxsw_sp, mdb->addr, fid);
 		if (!mid) {
 			netdev_err(dev, "Unable to allocate MC group\n");
 			return -ENOMEM;
@@ -1137,7 +1137,7 @@ static int mlxsw_sp_port_mdb_del(struct mlxsw_sp_port *mlxsw_sp_port,
 	u16 mid_idx;
 	int err = 0;
 
-	mid = __mlxsw_sp_mc_get(mlxsw_sp, mdb->addr, mdb->vid);
+	mid = __mlxsw_sp_mc_get(mlxsw_sp, mdb->addr, fid);
 	if (!mid) {
 		netdev_err(dev, "Unable to remove port from MC DB\n");
 		return -EINVAL;