RDMA/cxgb4: Only allow kernel db ringing for T4 devs

The whole db drop avoidance stuff is for T4 only.  So we cannot allow
that to be enabled for T5 devices.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
index f18ef34e8184..086f62f5dc9e 100644
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -1777,11 +1777,15 @@ int c4iw_ib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
         /*
          * Use SQ_PSN and RQ_PSN to pass in IDX_INC values for
          * ringing the queue db when we're in DB_FULL mode.
+         * Only allow this on T4 devices.
          */
         attrs.sq_db_inc = attr->sq_psn;
         attrs.rq_db_inc = attr->rq_psn;
         mask |= (attr_mask & IB_QP_SQ_PSN) ? C4IW_QP_ATTR_SQ_DB : 0;
         mask |= (attr_mask & IB_QP_RQ_PSN) ? C4IW_QP_ATTR_RQ_DB : 0;
+        if (is_t5(to_c4iw_qp(ibqp)->rhp->rdev.lldi.adapter_type) &&
+            (mask & (C4IW_QP_ATTR_SQ_DB|C4IW_QP_ATTR_RQ_DB)))
+                return -EINVAL;
 
         return c4iw_modify_qp(rhp, qhp, mask, &attrs, 0);
 }