RDMA/rxe: Protext kernel index from user space

In order to prevent user space from modifying the index that belongs to
the kernel for shared queues let the kernel use a local copy of the index
and copy any new values of that index to the shared rxe_queue_bus struct.

This adds more switch statements which decreases the performance of the
queue API. Move the type into the parameter list for these functions so
that the compiler can optimize out the switch statements when the explicit
type is known. Modify all the calls in the driver on performance paths to
pass in the explicit queue type.

Link: https://lore.kernel.org/r/20210527194748.662636-4-rpearsonhpe@gmail.com
Link: https://lore.kernel.org/linux-rdma/20210526165239.GP1002214@@nvidia.com/
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 34 insertions, 10 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 2b220659bddb..08f04222dd0d 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -293,13 +293,17 @@ static enum resp_states get_srq_wqe(struct rxe_qp *qp)
 	struct rxe_queue *q = srq->rq.queue;
 	struct rxe_recv_wqe *wqe;
 	struct ib_event ev;
+	unsigned int count;
 
 	if (srq->error)
 		return RESPST_ERR_RNR;
 
 	spin_lock_bh(&srq->rq.consumer_lock);
 
-	wqe = queue_head(q);
+	if (qp->is_user)
+		wqe = queue_head(q, QUEUE_TYPE_FROM_USER);
+	else
+		wqe = queue_head(q, QUEUE_TYPE_KERNEL);
 	if (!wqe) {
 		spin_unlock_bh(&srq->rq.consumer_lock);
 		return RESPST_ERR_RNR;
@@ -309,10 +313,15 @@ static enum resp_states get_srq_wqe(struct rxe_qp *qp)
 	memcpy(&qp->resp.srq_wqe, wqe, sizeof(qp->resp.srq_wqe));
 
 	qp->resp.wqe = &qp->resp.srq_wqe.wqe;
-	advance_consumer(q);
+	if (qp->is_user) {
+		advance_consumer(q, QUEUE_TYPE_FROM_USER);
+		count = queue_count(q, QUEUE_TYPE_FROM_USER);
+	} else {
+		advance_consumer(q, QUEUE_TYPE_KERNEL);
+		count = queue_count(q, QUEUE_TYPE_KERNEL);
+	}
 
-	if (srq->limit && srq->ibsrq.event_handler &&
-	    (queue_count(q) < srq->limit)) {
+	if (srq->limit && srq->ibsrq.event_handler && (count < srq->limit)) {
 		srq->limit = 0;
 		goto event;
 	}
@@ -339,7 +348,12 @@ static enum resp_states check_resource(struct rxe_qp *qp,
 			qp->resp.status = IB_WC_WR_FLUSH_ERR;
 			return RESPST_COMPLETE;
 		} else if (!srq) {
-			qp->resp.wqe = queue_head(qp->rq.queue);
+			if (qp->is_user)
+				qp->resp.wqe = queue_head(qp->rq.queue,
+						QUEUE_TYPE_FROM_USER);
+			else
+				qp->resp.wqe = queue_head(qp->rq.queue,
+						QUEUE_TYPE_KERNEL);
 			if (qp->resp.wqe) {
 				qp->resp.status = IB_WC_WR_FLUSH_ERR;
 				return RESPST_COMPLETE;
@@ -366,7 +380,12 @@ static enum resp_states check_resource(struct rxe_qp *qp,
 		if (srq)
 			return get_srq_wqe(qp);
 
-		qp->resp.wqe = queue_head(qp->rq.queue);
+		if (qp->is_user)
+			qp->resp.wqe = queue_head(qp->rq.queue,
+					QUEUE_TYPE_FROM_USER);
+		else
+			qp->resp.wqe = queue_head(qp->rq.queue,
+					QUEUE_TYPE_KERNEL);
 		return (qp->resp.wqe) ? RESPST_CHK_LENGTH : RESPST_ERR_RNR;
 	}
 
@@ -909,8 +928,12 @@ static enum resp_states do_complete(struct rxe_qp *qp,
 	}
 
 	/* have copy for srq and reference for !srq */
-	if (!qp->srq)
-		advance_consumer(qp->rq.queue);
+	if (!qp->srq) {
+		if (qp->is_user)
+			advance_consumer(qp->rq.queue, QUEUE_TYPE_FROM_USER);
+		else
+			advance_consumer(qp->rq.queue, QUEUE_TYPE_KERNEL);
+	}
 
 	qp->resp.wqe = NULL;
 
@@ -1176,6 +1199,7 @@ static enum resp_states do_class_d1e_error(struct rxe_qp *qp)
 static void rxe_drain_req_pkts(struct rxe_qp *qp, bool notify)
 {
 	struct sk_buff *skb;
+	struct rxe_queue *q = qp->rq.queue;
 
 	while ((skb = skb_dequeue(&qp->req_pkts))) {
 		rxe_drop_ref(qp);
@@ -1186,8 +1210,8 @@ static void rxe_drain_req_pkts(struct rxe_qp *qp, bool notify)
 	if (notify)
 		return;
 
-	while (!qp->srq && qp->rq.queue && queue_head(qp->rq.queue))
-		advance_consumer(qp->rq.queue);
+	while (!qp->srq && q && queue_head(q, q->type))
+		advance_consumer(q, q->type);
 }
 
 int rxe_responder(void *arg)