[PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr()

[YueHaibing]

If re-registering an MR in hns_roce_rereg_user_mr(), we should
return NULL instead of pass 0 to ERR_PTR.

Fixes: 4e9fc1dae2a9 ("RDMA/hns: Optimize the MR registration process")
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
 drivers/infiniband/hw/hns/hns_roce_mr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
index 006c84bb3f9f..7089ac780291 100644
--- a/drivers/infiniband/hw/hns/hns_roce_mr.c
+++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
@@ -352,7 +352,9 @@ struct ib_mr *hns_roce_rereg_user_mr(struct ib_mr *ibmr, int flags, u64 start,
 free_cmd_mbox:
 	hns_roce_free_cmd_mailbox(hr_dev, mailbox);
 
-	return ERR_PTR(ret);
+	if (ret)
+		return ERR_PTR(ret);
+	return NULL;
 }
 
 int hns_roce_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
-- 
2.17.1