From 269e9d1ed4336e53776adaf92c98dfc6e192b861 Mon Sep 17 00:00:00 2001 From: Andrew Boyer Date: Wed, 23 Nov 2016 12:39:19 -0500 Subject: [PATCH] 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 dd3d88adc0030..cb3fd4cb0daa6 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; } -- 2.39.5