mlx4: Fix vlan table overflow

Prevent overflow when trying to register more Vlans then the Vlan table in
HW is configured to.
Need to take into acount that the first 2 entries are reserved.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/port.c b/drivers/net/ethernet/mellanox/mlx4/port.c
index 609e0ec14ce..163a314c148 100644
--- a/drivers/net/ethernet/mellanox/mlx4/port.c
+++ b/drivers/net/ethernet/mellanox/mlx4/port.c
@@ -65,7 +65,7 @@ void mlx4_init_vlan_table(struct mlx4_dev *dev, struct mlx4_vlan_table *table)
                 table->entries[i] = 0;
                 table->refs[i]   = 0;
         }
-        table->max   = 1 << dev->caps.log_num_vlans;
+        table->max   = (1 << dev->caps.log_num_vlans) - MLX4_VLAN_REGULAR;
         table->total = 0;
 }
 
@@ -354,6 +354,13 @@ int mlx4_register_vlan(struct mlx4_dev *dev, u8 port, u16 vlan, int *index)
         int free = -1;
 
         mutex_lock(&table->mutex);
+
+        if (table->total == table->max) {
+                /* No free vlan entries */
+                err = -ENOSPC;
+                goto out;
+        }
+
         for (i = MLX4_VLAN_REGULAR; i < MLX4_MAX_VLAN_NUM; i++) {
                 if (free < 0 && (table->refs[i] == 0)) {
                         free = i;
@@ -375,12 +382,6 @@ int mlx4_register_vlan(struct mlx4_dev *dev, u8 port, u16 vlan, int *index)
                 goto out;
         }
 
-        if (table->total == table->max) {
-                /* No free vlan entries */
-                err = -ENOSPC;
-                goto out;
-        }
-
         /* Register new MAC */
         table->refs[free] = 1;
         table->entries[free] = cpu_to_be32(vlan | MLX4_VLAN_VALID);