IB/{rdmavt, hfi1, qib}: Remove AH refcount for UD QPs

Historically rdmavt destroy_ah() has returned an -EBUSY when the AH has a
non-zero reference count.  IBTA 11.2.2 notes no such return value or error
case:

	Output Modifiers:
	- Verb results:
	- Operation completed successfully.
	- Invalid HCA handle.
	- Invalid address handle.

ULPs never test for this error and this will leak memory.

The reference count exists to allow for driver independent progress
mechanisms to process UD SWQEs in parallel with post sends.  The SWQE will
hold a reference count until the UD SWQE completes and then drops the
reference.

Fix by removing need to reference count the AH.  Add a UD specific
allocation to each SWQE entry to cache the necessary information for
independent progress.  Copy the information during the post send
processing.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@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, 56 insertions, 8 deletions

diff --git a/drivers/infiniband/sw/rdmavt/ah.c b/drivers/infiniband/sw/rdmavt/ah.c
index 0e147b32cbe9..fe99da0ff060 100644
--- a/drivers/infiniband/sw/rdmavt/ah.c
+++ b/drivers/infiniband/sw/rdmavt/ah.c
@@ -1,5 +1,5 @@
 /*
- * Copyright(c) 2016 Intel Corporation.
+ * Copyright(c) 2016 - 2019 Intel Corporation.
  *
  * This file is provided under a dual BSD/GPLv2 license.  When using or
  * redistributing this file, you may do so under either license.
@@ -119,8 +119,6 @@ int rvt_create_ah(struct ib_ah *ibah, struct rdma_ah_attr *ah_attr,
 
 	rdma_copy_ah_attr(&ah->attr, ah_attr);
 
-	atomic_set(&ah->refcount, 0);
-
 	if (dev->driver_f.notify_new_ah)
 		dev->driver_f.notify_new_ah(ibah->device, ah_attr, ah);
 
@@ -141,8 +139,6 @@ void rvt_destroy_ah(struct ib_ah *ibah, u32 destroy_flags)
 	struct rvt_ah *ah = ibah_to_rvtah(ibah);
 	unsigned long flags;
 
-	WARN_ON_ONCE(atomic_read(&ah->refcount));
-
 	spin_lock_irqsave(&dev->n_ahs_lock, flags);
 	dev->n_ahs_allocated--;
 	spin_unlock_irqrestore(&dev->n_ahs_lock, flags);
diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index b9035d969057..de7d2edb9781 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -979,6 +979,51 @@ static u8 get_allowed_ops(enum ib_qp_type type)
 }
 
 /**
+ * free_ud_wq_attr - Clean up AH attribute cache for UD QPs
+ * @qp: Valid QP with allowed_ops set
+ *
+ * The rvt_swqe data structure being used is a union, so this is
+ * only valid for UD QPs.
+ */
+static void free_ud_wq_attr(struct rvt_qp *qp)
+{
+	struct rvt_swqe *wqe;
+	int i;
+
+	for (i = 0; qp->allowed_ops == IB_OPCODE_UD && i < qp->s_size; i++) {
+		wqe = rvt_get_swqe_ptr(qp, i);
+		kfree(wqe->ud_wr.attr);
+		wqe->ud_wr.attr = NULL;
+	}
+}
+
+/**
+ * alloc_ud_wq_attr - AH attribute cache for UD QPs
+ * @qp: Valid QP with allowed_ops set
+ * @node: Numa node for allocation
+ *
+ * The rvt_swqe data structure being used is a union, so this is
+ * only valid for UD QPs.
+ */
+static int alloc_ud_wq_attr(struct rvt_qp *qp, int node)
+{
+	struct rvt_swqe *wqe;
+	int i;
+
+	for (i = 0; qp->allowed_ops == IB_OPCODE_UD && i < qp->s_size; i++) {
+		wqe = rvt_get_swqe_ptr(qp, i);
+		wqe->ud_wr.attr = kzalloc_node(sizeof(*wqe->ud_wr.attr),
+					       GFP_KERNEL, node);
+		if (!wqe->ud_wr.attr) {
+			free_ud_wq_attr(qp);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+/**
  * rvt_create_qp - create a queue pair for a device
  * @ibpd: the protection domain who's device we create the queue pair for
  * @init_attr: the attributes of the queue pair
@@ -1124,6 +1169,11 @@ struct ib_qp *rvt_create_qp(struct ib_pd *ibpd,
 		qp->s_max_sge = init_attr->cap.max_send_sge;
 		if (init_attr->sq_sig_type == IB_SIGNAL_REQ_WR)
 			qp->s_flags = RVT_S_SIGNAL_REQ_WR;
+		err = alloc_ud_wq_attr(qp, rdi->dparms.node);
+		if (err) {
+			ret = (ERR_PTR(err));
+			goto bail_driver_priv;
+		}
 
 		err = alloc_qpn(rdi, &rdi->qp_dev->qpn_table,
 				init_attr->qp_type,
@@ -1227,6 +1277,7 @@ bail_qpn:
 
 bail_rq_wq:
 	rvt_free_rq(&qp->r_rq);
+	free_ud_wq_attr(qp);
 
 bail_driver_priv:
 	rdi->driver_f.qp_priv_free(rdi, qp);
@@ -1671,6 +1722,7 @@ int rvt_destroy_qp(struct ib_qp *ibqp, struct ib_udata *udata)
 	kfree(qp->s_ack_queue);
 	rdma_destroy_ah_attr(&qp->remote_ah_attr);
 	rdma_destroy_ah_attr(&qp->alt_ah_attr);
+	free_ud_wq_attr(qp);
 	vfree(qp->s_wq);
 	kfree(qp);
 	return 0;
@@ -2037,10 +2089,10 @@ static int rvt_post_one_wr(struct rvt_qp *qp,
 	 */
 	log_pmtu = qp->log_pmtu;
 	if (qp->allowed_ops == IB_OPCODE_UD) {
-		struct rvt_ah *ah = ibah_to_rvtah(wqe->ud_wr.ah);
+		struct rvt_ah *ah = ibah_to_rvtah(wqe->ud_wr.wr.ah);
 
 		log_pmtu = ah->log_pmtu;
-		atomic_inc(&ibah_to_rvtah(ud_wr(wr)->ah)->refcount);
+		rdma_copy_ah_attr(wqe->ud_wr.attr, &ah->attr);
 	}
 
 	if (rdi->post_parms[wr->opcode].flags & RVT_OPERATION_LOCAL) {
@@ -2085,7 +2137,7 @@ static int rvt_post_one_wr(struct rvt_qp *qp,
 
 bail_inval_free_ref:
 	if (qp->allowed_ops == IB_OPCODE_UD)
-		atomic_dec(&ibah_to_rvtah(ud_wr(wr)->ah)->refcount);
+		rdma_destroy_ah_attr(wqe->ud_wr.attr);
 bail_inval_free:
 	/* release mr holds */
 	while (j) {