1 files changed, 20 insertions, 15 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/port.c b/drivers/net/ethernet/mellanox/mlx4/port.c
index cfcad26ed40f..b5b3549b0c8d 100644
--- a/drivers/net/ethernet/mellanox/mlx4/port.c
+++ b/drivers/net/ethernet/mellanox/mlx4/port.c
@@ -1106,6 +1106,9 @@ int mlx4_get_slave_from_roce_gid(struct mlx4_dev *dev, int port, u8 *gid,
         }
 
         if (found_ix >= 0) {
+                /* Calculate a slave_gid which is the slave number in the gid
+                 * table and not a globally unique slave number.
+                 */
                 if (found_ix < MLX4_ROCE_PF_GIDS)
                         slave_gid = 0;
                 else if (found_ix < MLX4_ROCE_PF_GIDS + (vf_gids % num_vfs) *
@@ -1118,41 +1121,43 @@ int mlx4_get_slave_from_roce_gid(struct mlx4_dev *dev, int port, u8 *gid,
                           ((vf_gids % num_vfs) * ((vf_gids / num_vfs + 1)))) /
                          (vf_gids / num_vfs)) + vf_gids % num_vfs + 1;
 
+                /* Calculate the globally unique slave id */
                 if (slave_gid) {
                         struct mlx4_active_ports exclusive_ports;
                         struct mlx4_active_ports actv_ports;
                         struct mlx4_slaves_pport slaves_pport_actv;
                         unsigned max_port_p_one;
-                        int num_slaves_before = 1;
+                        int num_vfs_before = 0;
+                        int candidate_slave_gid;
 
+                        /* Calculate how many VFs are on the previous port, if exists */
                         for (i = 1; i < port; i++) {
                                 bitmap_zero(exclusive_ports.ports, dev->caps.num_ports);
-                                set_bit(i, exclusive_ports.ports);
+                                set_bit(i - 1, exclusive_ports.ports);
                                 slaves_pport_actv =
                                         mlx4_phys_to_slaves_pport_actv(
                                                         dev, &exclusive_ports);
-                                num_slaves_before += bitmap_weight(
+                                num_vfs_before += bitmap_weight(
                                                 slaves_pport_actv.slaves,
                                                 dev->num_vfs + 1);
                         }
 
-                        if (slave_gid < num_slaves_before) {
-                                bitmap_zero(exclusive_ports.ports, dev->caps.num_ports);
-                                set_bit(port - 1, exclusive_ports.ports);
-                                slaves_pport_actv =
-                                        mlx4_phys_to_slaves_pport_actv(
-                                                        dev, &exclusive_ports);
-                                slave_gid += bitmap_weight(
-                                                slaves_pport_actv.slaves,
-                                                dev->num_vfs + 1) -
-                                                num_slaves_before;
-                        }
-                        actv_ports = mlx4_get_active_ports(dev, slave_gid);
+                        /* candidate_slave_gid isn't necessarily the correct slave, but
+                         * it has the same number of ports and is assigned to the same
+                         * ports as the real slave we're looking for. On dual port VF,
+                         * slave_gid = [single port VFs on port <port>] +
+                         * [offset of the current slave from the first dual port VF] +
+                         * 1 (for the PF).
+                         */
+                        candidate_slave_gid = slave_gid + num_vfs_before;
+
+                        actv_ports = mlx4_get_active_ports(dev, candidate_slave_gid);
                         max_port_p_one = find_first_bit(
                                 actv_ports.ports, dev->caps.num_ports) +
                                 bitmap_weight(actv_ports.ports,
                                               dev->caps.num_ports) + 1;
 
+                        /* Calculate the real slave number */
                         for (i = 1; i < max_port_p_one; i++) {
                                 if (i == port)
                                         continue;