[PATCH v2 for-next] RDMA/hns: Add a check for current state before modifying QP

[Weihang Li <liweihang@huawei.com>]

From: Lang Cheng <chenglang@huawei.com>

It should be considered as an illegal operation if the ULP attempts to
modify a QP from another state to the current hardware state. Otherwise,
the ULP can modify some fields of QPC at any time. For example, for a QP in
state of RTS, modify it from RTR to RTS can change the PSN, which is always
not as expected.

Fixes: 9a4435375cd1 ("IB/hns: Add driver files for hns RoCE driver")
Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
---
Changes since v1:
- Add a fixes line as Jason suggested.

 drivers/infiniband/hw/hns/hns_roce_qp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_qp.c b/drivers/infiniband/hw/hns/hns_roce_qp.c
index e94ca13..bb87e5fc 100644
--- a/drivers/infiniband/hw/hns/hns_roce_qp.c
+++ b/drivers/infiniband/hw/hns/hns_roce_qp.c
@@ -1162,8 +1162,10 @@ int hns_roce_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 
 	mutex_lock(&hr_qp->mutex);
 
-	cur_state = attr_mask & IB_QP_CUR_STATE ?
-		    attr->cur_qp_state : (enum ib_qp_state)hr_qp->state;
+	if (attr_mask & IB_QP_CUR_STATE && attr->cur_qp_state != hr_qp->state)
+		goto out;
+
+	cur_state = hr_qp->state;
 	new_state = attr_mask & IB_QP_STATE ? attr->qp_state : cur_state;
 
 	if (ibqp->uobject &&
-- 
2.8.1