1 files changed, 24 insertions, 17 deletions

diff --git a/drivers/infiniband/sw/rdmavt/rc.c b/drivers/infiniband/sw/rdmavt/rc.c
index 09f0cf538be6..890d7b760d2e 100644
--- a/drivers/infiniband/sw/rdmavt/rc.c
+++ b/drivers/infiniband/sw/rdmavt/rc.c
@@ -104,26 +104,33 @@ __be32 rvt_compute_aeth(struct rvt_qp *qp)
 	} else {
 		u32 min, max, x;
 		u32 credits;
-		struct rvt_rwq *wq = qp->r_rq.wq;
 		u32 head;
 		u32 tail;
 
-		/* sanity check pointers before trusting them */
-		head = wq->head;
-		if (head >= qp->r_rq.size)
-			head = 0;
-		tail = wq->tail;
-		if (tail >= qp->r_rq.size)
-			tail = 0;
-		/*
-		 * Compute the number of credits available (RWQEs).
-		 * There is a small chance that the pair of reads are
-		 * not atomic, which is OK, since the fuzziness is
-		 * resolved as further ACKs go out.
-		 */
-		credits = head - tail;
-		if ((int)credits < 0)
-			credits += qp->r_rq.size;
+		credits = READ_ONCE(qp->r_rq.kwq->count);
+		if (credits == 0) {
+			/* sanity check pointers before trusting them */
+			if (qp->ip) {
+				head = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->head);
+				tail = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->tail);
+			} else {
+				head = READ_ONCE(qp->r_rq.kwq->head);
+				tail = READ_ONCE(qp->r_rq.kwq->tail);
+			}
+			if (head >= qp->r_rq.size)
+				head = 0;
+			if (tail >= qp->r_rq.size)
+				tail = 0;
+			/*
+			 * Compute the number of credits available (RWQEs).
+			 * There is a small chance that the pair of reads are
+			 * not atomic, which is OK, since the fuzziness is
+			 * resolved as further ACKs go out.
+			 */
+			credits = head - tail;
+			if ((int)credits < 0)
+				credits += qp->r_rq.size;
+		}
 		/*
 		 * Binary search the credit table to find the code to
 		 * use.