IB/{hfi1, qib, rdmavt}: Schedule multi RC/UC packets instead of posting

The post_send() path determines if it should post directly or, schedule
the post for later.  The current logic is:

  if the swqe ring is empty or (for hfi1) wqe->length <= piothreshold
    post the send
  else
    schedule

This can allow large requests to call the send engine directly.  Large
requests can potentially produce a large number of packets prior to
returning to the caller, blocking the caller from posting more requests,
and allowing better parallel processing.

Allow the driver(s) more say in this logic (pass call_send to the driver,
rather than examining a return value).

Update hfi1/qib logic to schedule the send engine if an RC or UC message
is larger than the QP MTU size.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

2 files changed, 9 insertions, 11 deletions

diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 344e401915f7..a81905df2d0f 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -378,25 +378,22 @@ void qib_flush_qp_waiters(struct rvt_qp *qp)
  * qib_check_send_wqe - validate wr/wqe
  * @qp - The qp
  * @wqe - The built wqe
+ * @call_send - Determine if the send should be posted or scheduled
  *
- * validate wr/wqe.  This is called
- * prior to inserting the wqe into
- * the ring but after the wqe has been
- * setup.
- *
- * Returns 1 to force direct progress, 0 otherwise, -EINVAL on failure
+ * Returns 0 on success, -EINVAL on failure
  */
 int qib_check_send_wqe(struct rvt_qp *qp,
-		       struct rvt_swqe *wqe)
+		       struct rvt_swqe *wqe, bool *call_send)
 {
 	struct rvt_ah *ah;
-	int ret = 0;
 
 	switch (qp->ibqp.qp_type) {
 	case IB_QPT_RC:
 	case IB_QPT_UC:
 		if (wqe->length > 0x80000000U)
 			return -EINVAL;
+		if (wqe->length > qp->pmtu)
+			*call_send = false;
 		break;
 	case IB_QPT_SMI:
 	case IB_QPT_GSI:
@@ -405,12 +402,12 @@ int qib_check_send_wqe(struct rvt_qp *qp,
 		if (wqe->length > (1 << ah->log_pmtu))
 			return -EINVAL;
 		/* progress hint */
-		ret = 1;
+		*call_send = true;
 		break;
 	default:
 		break;
 	}
-	return ret;
+	return 0;
 }
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/drivers/infiniband/hw/qib/qib_verbs.h b/drivers/infiniband/hw/qib/qib_verbs.h
index 666613eef88f..3d7b744ae8fb 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.h
+++ b/drivers/infiniband/hw/qib/qib_verbs.h
@@ -303,7 +303,8 @@ void qib_rc_rcv(struct qib_ctxtdata *rcd, struct ib_header *hdr,
 
 int qib_check_ah(struct ib_device *ibdev, struct rdma_ah_attr *ah_attr);
 
-int qib_check_send_wqe(struct rvt_qp *qp, struct rvt_swqe *wqe);
+int qib_check_send_wqe(struct rvt_qp *qp, struct rvt_swqe *wqe,
+		       bool *call_send);
 
 struct ib_ah *qib_create_qp0_ah(struct qib_ibport *ibp, u16 dlid);