From: Ganesh Goudar <ganeshgr@chelsio.com>
Date: Wed, 21 Jun 2017 19:55:43 +0530
Subject: iw_cxgb4: don't use WR keys/addrs for 0 byte reads
Patch-mainline: v4.13-rc2
Git-commit: 720336c42e41a917002fcae3aa14e30f5022bbb7
References: bsc#1046543

Only use the read sge lkey/addr and the remote rkey/addr if the
length of the read is not zero. Otherwise the read response might
be treated as the RTR read response and not delivered to the
application. Or worse Terminator hardware will fail a 0B read
if the STAG is 0 even if the read length is 0.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/cxgb4/qp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -569,7 +569,7 @@ static int build_rdma_read(union t4_wr *
 {
 	if (wr->num_sge > 1)
 		return -EINVAL;
-	if (wr->num_sge) {
+	if (wr->num_sge && wr->sg_list[0].length) {
 		wqe->read.stag_src = cpu_to_be32(rdma_wr(wr)->rkey);
 		wqe->read.to_src_hi = cpu_to_be32((u32)(rdma_wr(wr)->remote_addr
 							>> 32));