From: =?UTF-8?q?H=C3=A5kon=20Bugge?= <haakon.bugge@oracle.com>
Date: Wed, 4 Jul 2018 12:48:01 +0200
Subject: IB/cm: Remove unused and erroneous msg sequence encoding
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Content-Transfer-Encoding: 8bit
Patch-mainline: v4.19-rc1
Git-commit: 87a37ce9e400e40daee537ff95343e3c94743c6d
References: bsc#1103992 FATE#326009

In cm_form_tid(), a two bit message sequence number is OR'ed into bit
31-30 of the lower TID value.

After commit f06d26537559 ("IB/cm: Randomize starting comm ID"), the
local_id is XOR'ed with a 32-bit random value. Hence, bit 31-30 in the
lower TID now has an arbitrarily value and it makes no sense to OR in
the message sequence number.

Adding to that, the evolution in use of IDR routines in cm_alloc_id()
has always had the possibility of returning a value with bit 30 set.

In addition, said bits are never checked.

Hence, remove the encoding and the corresponding enum.

Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/cm.c      |   14 ++++++--------
 drivers/infiniband/core/cm_msgs.h |    7 -------
 2 files changed, 6 insertions(+), 15 deletions(-)

--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -1256,14 +1256,12 @@ new_id:
 }
 EXPORT_SYMBOL(ib_cm_insert_listen);
 
-static __be64 cm_form_tid(struct cm_id_private *cm_id_priv,
-			  enum cm_msg_sequence msg_seq)
+static __be64 cm_form_tid(struct cm_id_private *cm_id_priv)
 {
 	u64 hi_tid, low_tid;
 
 	hi_tid   = ((u64) cm_id_priv->av.port->mad_agent->hi_tid) << 32;
-	low_tid  = (u64) ((__force u32)cm_id_priv->id.local_id |
-			  (msg_seq << 30));
+	low_tid  = (u64)cm_id_priv->id.local_id;
 	return cpu_to_be64(hi_tid | low_tid);
 }
 
@@ -1291,7 +1289,7 @@ static void cm_format_req(struct cm_req_
 					      pri_path->opa.slid);
 
 	cm_format_mad_hdr(&req_msg->hdr, CM_REQ_ATTR_ID,
-			  cm_form_tid(cm_id_priv, CM_MSG_SEQUENCE_REQ));
+			  cm_form_tid(cm_id_priv));
 
 	req_msg->local_comm_id = cm_id_priv->id.local_id;
 	req_msg->service_id = param->service_id;
@@ -2465,7 +2463,7 @@ static void cm_format_dreq(struct cm_dre
 			  u8 private_data_len)
 {
 	cm_format_mad_hdr(&dreq_msg->hdr, CM_DREQ_ATTR_ID,
-			  cm_form_tid(cm_id_priv, CM_MSG_SEQUENCE_DREQ));
+			  cm_form_tid(cm_id_priv));
 	dreq_msg->local_comm_id = cm_id_priv->id.local_id;
 	dreq_msg->remote_comm_id = cm_id_priv->id.remote_id;
 	cm_dreq_set_remote_qpn(dreq_msg, cm_id_priv->remote_qpn);
@@ -3096,7 +3094,7 @@ static void cm_format_lap(struct cm_lap_
 		alt_ext = opa_is_extended_lid(alternate_path->opa.dlid,
 					      alternate_path->opa.slid);
 	cm_format_mad_hdr(&lap_msg->hdr, CM_LAP_ATTR_ID,
-			  cm_form_tid(cm_id_priv, CM_MSG_SEQUENCE_LAP));
+			  cm_form_tid(cm_id_priv));
 	lap_msg->local_comm_id = cm_id_priv->id.local_id;
 	lap_msg->remote_comm_id = cm_id_priv->id.remote_id;
 	cm_lap_set_remote_qpn(lap_msg, cm_id_priv->remote_qpn);
@@ -3472,7 +3470,7 @@ static void cm_format_sidr_req(struct cm
 			       struct ib_cm_sidr_req_param *param)
 {
 	cm_format_mad_hdr(&sidr_req_msg->hdr, CM_SIDR_REQ_ATTR_ID,
-			  cm_form_tid(cm_id_priv, CM_MSG_SEQUENCE_SIDR));
+			  cm_form_tid(cm_id_priv));
 	sidr_req_msg->request_id = cm_id_priv->id.local_id;
 	sidr_req_msg->pkey = param->path->pkey;
 	sidr_req_msg->service_id = param->service_id;
--- a/drivers/infiniband/core/cm_msgs.h
+++ b/drivers/infiniband/core/cm_msgs.h
@@ -44,13 +44,6 @@
 
 #define IB_CM_CLASS_VERSION	2 /* IB specification 1.2 */
 
-enum cm_msg_sequence {
-	CM_MSG_SEQUENCE_REQ,
-	CM_MSG_SEQUENCE_LAP,
-	CM_MSG_SEQUENCE_DREQ,
-	CM_MSG_SEQUENCE_SIDR
-};
-
 struct cm_req_msg {
 	struct ib_mad_hdr hdr;