From: Bob Pearson <rpearsonhpe@gmail.com>
Date: Mon, 18 Apr 2022 12:41:04 -0500
Subject: RDMA/rxe: Recheck the MR in when generating a READ reply
Patch-mainline: v5.18-rc6
Git-commit: 570a4bf7440e9fb2a4164244a6bf60a46362b627
References: jsc#PED-1111

The rping benchmark fails on long runs. The root cause of this failure has
been traced to a failure to compute a nonzero value of mr in rare
situations.

Fix this failure by correctly handling the computation of mr in
read_reply() in rxe_resp.c in the replay flow.

Fixes: 8a1a0be894da ("RDMA/rxe: Replace mr by rkey in responder resources")
Link: https://lore.kernel.org/r/20220418174103.3040-1-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/sw/rxe/rxe_resp.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -745,8 +745,14 @@ static enum resp_states read_reply(struc
 	}
 
 	if (res->state == rdatm_res_state_new) {
-		mr = qp->resp.mr;
-		qp->resp.mr = NULL;
+		if (!res->replay) {
+			mr = qp->resp.mr;
+			qp->resp.mr = NULL;
+		} else {
+			mr = rxe_recheck_mr(qp, res->read.rkey);
+			if (!mr)
+				return RESPST_ERR_RKEY_VIOLATION;
+		}
 
 		if (res->read.resid <= mtu)
 			opcode = IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY;