RDMA/hns: Fix memory leak on 'context' on error return path

Currently, the error return path when the call to function
dev->dfx->query_cqc_info fails will leak object 'context'. Fix this by
making the error return path via 'err' return return codes rather than
-EMSGSIZE, set ret appropriately for all error return paths and for the
memory leak now return via 'err' rather than just returning without
freeing context.

Link: https://lore.kernel.org/r/20191024131034.19989-1-colin.king@canonical.com
Addresses-Coverity: ("Resource leak")
Fixes: e1c9a0dc29 ("RDMA/hns: Dump detailed driver-specific CQ")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hns/hns_roce_restrack.c

@@ -95,14 +95,18 @@ static int hns_roce_fill_res_cq_entry(struct sk_buff *msg,
 
 	ret = hr_dev->dfx->query_cqc_info(hr_dev, hr_cq->cqn, (int *)context);
 	if (ret)
-		return -EINVAL;
-
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
-	if (!table_attr)
 		goto err;
 
-	if (hns_roce_fill_cq(msg, context))
+	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
+	if (!table_attr) {
+		ret = -EMSGSIZE;
+		goto err;
+	}
+
+	if (hns_roce_fill_cq(msg, context)) {
+		ret = -EMSGSIZE;
 		goto err_cancel_table;
+	}
 
 	nla_nest_end(msg, table_attr);
 	kfree(context);
@@ -113,7 +117,7 @@ err_cancel_table:
 	nla_nest_cancel(msg, table_attr);
 err:
 	kfree(context);
-	return -EMSGSIZE;
+	return ret;
 }
 
 int hns_roce_fill_res_entry(struct sk_buff *msg,