IB/hns: Fix bug of using uninit refcount and free

In current version, it uses uninitialized parameters named
refcount and free in hns_roce_cq_event.
This patch initializes these parameter in cq alloc and add
correspond process in cq free.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Dongdong Huang(Donald) <hdd.huang@huawei.com>
Reviewed-by: Wei Hu <xavier.huwei@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hns/hns_roce_cq.c

@@ -152,6 +152,9 @@ static int hns_roce_cq_alloc(struct hns_roce_dev *hr_dev, int nent,
 	hr_cq->cons_index = 0;
 	hr_cq->uar = hr_uar;
 
+	atomic_set(&hr_cq->refcount, 1);
+	init_completion(&hr_cq->free);
+
 	return 0;
 
 err_radix:
@@ -191,6 +194,11 @@ static void hns_roce_free_cq(struct hns_roce_dev *hr_dev,
 	/* Waiting interrupt process procedure carried out */
 	synchronize_irq(hr_dev->eq_table.eq[hr_cq->vector].irq);
 
+	/* wait for all interrupt processed */
+	if (atomic_dec_and_test(&hr_cq->refcount))
+		complete(&hr_cq->free);
+	wait_for_completion(&hr_cq->free);
+
 	spin_lock_irq(&cq_table->lock);
 	radix_tree_delete(&cq_table->tree, hr_cq->cqn);
 	spin_unlock_irq(&cq_table->lock);