From: Lijun Ou <oulijun@huawei.com>
Date: Mon, 24 Jun 2019 19:47:49 +0800
Subject: RDMA/hns: Bugfix for calculating qp buffer size
Patch-mainline: v5.3-rc1
Git-commit: e0222d18d628ce96f0def790ea26b6b7b3c18f78
References: bsc#1104427 FATE#326416

The buffer size of qp which used to allocate qp buffer space for storing
sqwqe and rqwqe will be the length of buffer space. The kernel driver will
use the buffer address and the same size to get the user memory. The same
size named buff_size of qp. According the algorithm of calculating, The
size of the two is not equal when users set the max sge of sq.

Fixes: b28ca7cceff8 ("RDMA/hns: Limit extend sq sge num")
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/hns/hns_roce_qp.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/hw/hns/hns_roce_qp.c
+++ b/drivers/infiniband/hw/hns/hns_roce_qp.c
@@ -407,8 +407,8 @@ static int hns_roce_set_user_sq_size(str
 					     hr_qp->sq.wqe_shift), PAGE_SIZE);
 	} else {
 		page_size = 1 << (hr_dev->caps.mtt_buf_pg_sz + PAGE_SHIFT);
-		hr_qp->sge.sge_cnt =
-		       max(page_size / (1 << hr_qp->sge.sge_shift), ex_sge_num);
+		hr_qp->sge.sge_cnt = ex_sge_num ?
+		   max(page_size / (1 << hr_qp->sge.sge_shift), ex_sge_num) : 0;
 		hr_qp->buff_size = HNS_ROCE_ALOGN_UP((hr_qp->rq.wqe_cnt <<
 					     hr_qp->rq.wqe_shift), page_size) +
 				   HNS_ROCE_ALOGN_UP((hr_qp->sge.sge_cnt <<