From 2a7a85487e5432424eef7a394ed26ef1d8f0d192 Mon Sep 17 00:00:00 2001 From: Andrew Boyer Date: Wed, 23 Nov 2016 12:39:19 -0500 Subject: IB/rxe: Don't update the response PSN unless it's going forwards A client might post a read followed by a send. The partner receives and acknowledges both transactions, posting an RCQ entry for the send, but something goes wrong with the read ACK. When the client retries the read, the partner's responder processes the duplicate read but incorrectly resets the PSN to the value preceding the original send. When the duplicate send arrives, the responder cannot tell that it is a duplicate, so the responder generates a duplicate RCQ entry, confusing the client. Signed-off-by: Andrew Boyer Reviewed-by: Yonatan Cohen Signed-off-by: Doug Ledford --- drivers/infiniband/sw/rxe/rxe_resp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index dd3d88adc003..cb3fd4cb0daa 100644 --- a/drivers/infiniband/sw/rxe/rxe_resp.c +++ b/drivers/infiniband/sw/rxe/rxe_resp.c @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct rxe_qp *qp, } else { qp->resp.res = NULL; qp->resp.opcode = -1; - qp->resp.psn = res->cur_psn; + if (psn_compare(res->cur_psn, qp->resp.psn) >= 0) + qp->resp.psn = res->cur_psn; state = RESPST_CLEANUP; } -- cgit v1.2.3-59-g8ed1b