IB/hfi1: Add additional checks when handling TID RDMA READ RESP packet

In a congested fabric with adaptive routing enabled, traces show that
packets could be delivered out of order, which could cause incorrect
processing of stale packets. For stale TID RDMA READ RESP packets that
cause KDETH EFLAGS errors, this patch adds additional checks before
processing the packets.

Fixes: 9905bf06e8 ("IB/hfi1: Add functions to receive TID RDMA READ response")
Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Link: https://lore.kernel.org/r/20190815192045.105923.59813.stgit@awfm-01.aw.intel.com
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/tid_rdma.c

@@ -2740,9 +2740,12 @@ static bool handle_read_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 
 		wqe = do_rc_completion(qp, wqe, ibp);
 		if (qp->s_acked == qp->s_tail)
-			break;
+			goto s_unlock;
 	}
 
+	if (qp->s_acked == qp->s_tail)
+		goto s_unlock;
+
 	/* Handle the eflags for the request */
 	if (wqe->wr.opcode != IB_WR_TID_RDMA_READ)
 		goto s_unlock;