mlx4: Add ref counting to port MAC table for RoCE

The IB side of RoCE requires the MAC table index of the
MAC address used by its QPs.

To obtain the real MAC index, the IB side registers the
MAC (increasing its ref count, and also returning the
real MAC index) during the modify-qp sequence.

This protects against the ETH side deleting or modifying
that MAC table entry while the QP is active.

Note that until the modify-qp command returns success,
the MAC and VLAN information only has "candidate" status.
If the modify-qp succeeds, the "candidate" info is promoted
to the operational MAC/VLAN info for the qp. If the modify fails,
the candidate MAC/VLAN is unregistered, and the old qp info
is preserved.

The patch is a bit complex, because there are multiple qp
transitions where the primary-path information may be
modified:  INIT-to-RTR, and SQD-to-SQD.

Similarly for the alternate path information.

Therefore the code must handle cases where path information
has already been entered into the QP context by previous
qp transitions.

For the MAC address, the success logic is as follows:
1. If there was no previous MAC, simply move the candidate
   MAC information to the operational information, and reset
   the candidate MAC info.
2. If there was a previous MAC, unregister it.  Then move
   the MAC information from candidate to operational, and
   reset the candidate info (as in 1. above).

The MAC address failure logic is the same for all cases:
 - Unregister the candidate MAC, and reset the candidate MAC info.

For Vlan registration, the logic is similar.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h b/drivers/infiniband/hw/mlx4/mlx4_ib.h
index a230683af94..febc8f9bc59 100644
--- a/drivers/infiniband/hw/mlx4/mlx4_ib.h
+++ b/drivers/infiniband/hw/mlx4/mlx4_ib.h
@@ -241,6 +241,22 @@ struct mlx4_ib_proxy_sqp_hdr {
 	struct mlx4_rcv_tunnel_hdr tun;
 }  __packed;
 
+struct mlx4_roce_smac_vlan_info {
+	u64 smac;
+	int smac_index;
+	int smac_port;
+	u64 candidate_smac;
+	int candidate_smac_index;
+	int candidate_smac_port;
+	u16 vid;
+	int vlan_index;
+	int vlan_port;
+	u16 candidate_vid;
+	int candidate_vlan_index;
+	int candidate_vlan_port;
+	int update_vid;
+};
+
 struct mlx4_ib_qp {
 	struct ib_qp		ibqp;
 	struct mlx4_qp		mqp;
@@ -273,8 +289,9 @@ struct mlx4_ib_qp {
 	struct list_head	gid_list;
 	struct list_head	steering_rules;
 	struct mlx4_ib_buf	*sqp_proxy_rcv;
+	struct mlx4_roce_smac_vlan_info pri;
+	struct mlx4_roce_smac_vlan_info alt;
 	u64			reg_id;
-
 };
 
 struct mlx4_ib_srq {