net/rds: Assign the correct service level

Commit 2bbf615 ("net/rds: remove the RDS specific path record
caching") has changed the service level (SL) to TOS mapping to be
1:1. Nevertheless, it has assigned the SL to be a 8-bit value even though
IB specification section 7.7.3 mentioned that the SL is only a 4-bit
field. Thus, this patch assigns the SL correctly.

Orabug: 27607211

Signed-off-by: Wei Lin Guay <[email protected]>
Reported-by: Håkon Bugge <[email protected]>
Reviewed-by: Yuval Shaia <[email protected]>
Signed-off-by: Somasundaram Krishnasamy <[email protected]>

Orabug: 33590097

UEK6 => UEK7

(cherry picked from commit 42eca82)
cherry-pick-repo=UEK/production/linux-uek.git

Signed-off-by: Gerd Rausch <[email protected]>
Reviewed-by: William Kucharski <[email protected]>

Orabug: 33590087

UEK7 => LUCI

(cherry picked from commit 31d0359)
cherry-pick-repo=UEK/production/linux-uek.git

Signed-off-by: Gerd Rausch <[email protected]>
Reviewed-by: William Kucharski <[email protected]>

Author: Wei Lin Guay

net/rds/rdma_transport.c

@@ -162,7 +162,7 @@ int rds_rdma_cm_event_handler_cmn(struct rdma_cm_id *cm_id,
 				 * needs to update the sl manually. As for now, RDS is assuming
 				 * that it is a 1:1 in tos to sl mapping.
 				 */
-				cm_id->route.path_rec[0].sl = conn->c_tos;
+				cm_id->route.path_rec[0].sl = TOS_TO_SL(conn->c_tos);
 				cm_id->route.path_rec[0].qos_class = conn->c_tos;
 				ret = trans->cm_initiate_connect(cm_id, isv6);
 			} else {

net/rds/rdma_transport.h

@@ -7,6 +7,9 @@
 
 #define RDS_RDMA_RESOLVE_TIMEOUT_MS     5000
 
+/* Per IB specification 7.7.3, service level is a 4-bit field. */
+#define TOS_TO_SL(tos)	((tos) & 0xF)
+
 int rds_rdma_conn_connect(struct rds_connection *conn);
 int rds_rdma_cm_event_handler(struct rdma_cm_id *cm_id,
 			      struct rdma_cm_event *event);