[PATCH AUTOSEL for 4.9 049/100] IB/rxe: increment msn only when completing a request

From: alexander . levin
Date: Tue Dec 12 2017 - 21:40:04 EST


From: David Marchand <david.marchand@xxxxxxxxx>

[ Upstream commit 9fcd67d1772c43d2f23e8fca56acc7219e991676 ]

According to C9-147, MSN should only be incremented when the last packet of
a multi packet request has been received.

"Logically, the requester associates a sequential Send Sequence Number
(SSN) with each WQE posted to the send queue. The SSN bears a one-
to-one relationship to the MSN returned by the responder in each re-
sponse packet. Therefore, when the requester receives a response, it in-
terprets the MSN as representing the SSN of the most recent request
completed by the responder to determine which send WQE(s) can be
completed."

Fixes: 8700e3e7c485 ("Soft RoCE driver")

Signed-off-by: David Marchand <david.marchand@xxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 7705820cdac6..8c0ddd7165ae 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -799,18 +799,17 @@ static enum resp_states execute(struct rxe_qp *qp, struct rxe_pkt_info *pkt)
/* Unreachable */
WARN_ON(1);

- /* We successfully processed this new request. */
- qp->resp.msn++;
-
/* next expected psn, read handles this separately */
qp->resp.psn = (pkt->psn + 1) & BTH_PSN_MASK;

qp->resp.opcode = pkt->opcode;
qp->resp.status = IB_WC_SUCCESS;

- if (pkt->mask & RXE_COMP_MASK)
+ if (pkt->mask & RXE_COMP_MASK) {
+ /* We successfully processed this new request. */
+ qp->resp.msn++;
return RESPST_COMPLETE;
- else if (qp_type(qp) == IB_QPT_RC)
+ } else if (qp_type(qp) == IB_QPT_RC)
return RESPST_ACKNOWLEDGE;
else
return RESPST_CLEANUP;
--
2.11.0