RDMA/rxe: Add a type flag to rxe_queue structs

To create optimal code only want to use smp_load_acquire() and
smp_store_release() for user indices in rxe_queue APIs since kernel
indices are protected by locks which also act as memory barriers. By
adding a type to the queues we can determine which indices need to be
protected.

Link: https://lore.kernel.org/r/20210527194748.662636-2-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

5 files changed, 28 insertions, 13 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_cq.c b/drivers/infiniband/sw/rxe/rxe_cq.c
index b315ebf041ac..1d4d8a31bc12 100644
--- a/drivers/infiniband/sw/rxe/rxe_cq.c
+++ b/drivers/infiniband/sw/rxe/rxe_cq.c
@@ -59,9 +59,11 @@ int rxe_cq_from_init(struct rxe_dev *rxe, struct rxe_cq *cq, int cqe,
 		     struct rxe_create_cq_resp __user *uresp)
 {
 	int err;
+	enum queue_type type;
 
+	type = uresp ? QUEUE_TYPE_TO_USER : QUEUE_TYPE_KERNEL;
 	cq->queue = rxe_queue_init(rxe, &cqe,
-				   sizeof(struct rxe_cqe));
+			sizeof(struct rxe_cqe), type);
 	if (!cq->queue) {
 		pr_warn("unable to create cq\n");
 		return -ENOMEM;
diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 34ae957a315c..9bd6bf8f9bd9 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -206,6 +206,7 @@ static int rxe_qp_init_req(struct rxe_dev *rxe, struct rxe_qp *qp,
 {
 	int err;
 	int wqe_size;
+	enum queue_type type;
 
 	err = sock_create_kern(&init_net, AF_INET, SOCK_DGRAM, 0, &qp->sk);
 	if (err < 0)
@@ -231,7 +232,9 @@ static int rxe_qp_init_req(struct rxe_dev *rxe, struct rxe_qp *qp,
 	qp->sq.max_inline = init->cap.max_inline_data = wqe_size;
 	wqe_size += sizeof(struct rxe_send_wqe);
 
-	qp->sq.queue = rxe_queue_init(rxe, &qp->sq.max_wr, wqe_size);
+	type = uresp ? QUEUE_TYPE_FROM_USER : QUEUE_TYPE_KERNEL;
+	qp->sq.queue = rxe_queue_init(rxe, &qp->sq.max_wr,
+				wqe_size, type);
 	if (!qp->sq.queue)
 		return -ENOMEM;
 
@@ -273,6 +276,7 @@ static int rxe_qp_init_resp(struct rxe_dev *rxe, struct rxe_qp *qp,
 {
 	int err;
 	int wqe_size;
+	enum queue_type type;
 
 	if (!qp->srq) {
 		qp->rq.max_wr		= init->cap.max_recv_wr;
@@ -283,9 +287,9 @@ static int rxe_qp_init_resp(struct rxe_dev *rxe, struct rxe_qp *qp,
 		pr_debug("qp#%d max_wr = %d, max_sge = %d, wqe_size = %d\n",
 			 qp_num(qp), qp->rq.max_wr, qp->rq.max_sge, wqe_size);
 
-		qp->rq.queue = rxe_queue_init(rxe,
-					      &qp->rq.max_wr,
-					      wqe_size);
+		type = uresp ? QUEUE_TYPE_FROM_USER : QUEUE_TYPE_KERNEL;
+		qp->rq.queue = rxe_queue_init(rxe, &qp->rq.max_wr,
+					wqe_size, type);
 		if (!qp->rq.queue)
 			return -ENOMEM;
 
diff --git a/drivers/infiniband/sw/rxe/rxe_queue.c b/drivers/infiniband/sw/rxe/rxe_queue.c
index fa69241b1187..8f844d0b9e77 100644
--- a/drivers/infiniband/sw/rxe/rxe_queue.c
+++ b/drivers/infiniband/sw/rxe/rxe_queue.c
@@ -52,9 +52,8 @@ inline void rxe_queue_reset(struct rxe_queue *q)
 	memset(q->buf->data, 0, q->buf_size - sizeof(struct rxe_queue_buf));
 }
 
-struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
-				 int *num_elem,
-				 unsigned int elem_size)
+struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe, int *num_elem,
+			unsigned int elem_size, enum queue_type type)
 {
 	struct rxe_queue *q;
 	size_t buf_size;
@@ -69,6 +68,7 @@ struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
 		goto err1;
 
 	q->rxe = rxe;
+	q->type = type;
 
 	/* used in resize, only need to copy used part of queue */
 	q->elem_size = elem_size;
@@ -136,7 +136,7 @@ int rxe_queue_resize(struct rxe_queue *q, unsigned int *num_elem_p,
 	int err;
 	unsigned long flags = 0, flags1;
 
-	new_q = rxe_queue_init(q->rxe, &num_elem, elem_size);
+	new_q = rxe_queue_init(q->rxe, &num_elem, elem_size, q->type);
 	if (!new_q)
 		return -ENOMEM;
 
diff --git a/drivers/infiniband/sw/rxe/rxe_queue.h b/drivers/infiniband/sw/rxe/rxe_queue.h
index 2902ca7b288c..4512745419f8 100644
--- a/drivers/infiniband/sw/rxe/rxe_queue.h
+++ b/drivers/infiniband/sw/rxe/rxe_queue.h
@@ -19,6 +19,13 @@
  * of the queue is one less than the number of element slots
  */
 
+/* type of queue */
+enum queue_type {
+	QUEUE_TYPE_KERNEL,
+	QUEUE_TYPE_TO_USER,
+	QUEUE_TYPE_FROM_USER,
+};
+
 struct rxe_queue {
 	struct rxe_dev		*rxe;
 	struct rxe_queue_buf	*buf;
@@ -27,6 +34,7 @@ struct rxe_queue {
 	size_t			elem_size;
 	unsigned int		log2_elem_size;
 	u32			index_mask;
+	enum queue_type		type;
 };
 
 int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
@@ -35,9 +43,8 @@ int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
 
 void rxe_queue_reset(struct rxe_queue *q);
 
-struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
-				 int *num_elem,
-				 unsigned int elem_size);
+struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe, int *num_elem,
+			unsigned int elem_size, enum queue_type type);
 
 int rxe_queue_resize(struct rxe_queue *q, unsigned int *num_elem_p,
 		     unsigned int elem_size, struct ib_udata *udata,
diff --git a/drivers/infiniband/sw/rxe/rxe_srq.c b/drivers/infiniband/sw/rxe/rxe_srq.c
index 41b0d1e11baf..52c5593741ec 100644
--- a/drivers/infiniband/sw/rxe/rxe_srq.c
+++ b/drivers/infiniband/sw/rxe/rxe_srq.c
@@ -78,6 +78,7 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq *srq,
 	int err;
 	int srq_wqe_size;
 	struct rxe_queue *q;
+	enum queue_type type;
 
 	srq->ibsrq.event_handler	= init->event_handler;
 	srq->ibsrq.srq_context		= init->srq_context;
@@ -91,8 +92,9 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq *srq,
 	spin_lock_init(&srq->rq.producer_lock);
 	spin_lock_init(&srq->rq.consumer_lock);
 
+	type = uresp ? QUEUE_TYPE_FROM_USER : QUEUE_TYPE_KERNEL;
 	q = rxe_queue_init(rxe, &srq->rq.max_wr,
-			   srq_wqe_size);
+			srq_wqe_size, type);
 	if (!q) {
 		pr_warn("unable to allocate queue for srq\n");
 		return -ENOMEM;