RDMA/hns: Fix Use-After-Free of rsv_qp on HIP08

Currently rsv_qp is freed before ib_unregister_device() is called
on HIP08. During the time interval, users can still dereg MR and
rsv_qp will be used in this process, leading to a UAF. Move the
release of rsv_qp after calling ib_unregister_device() to fix it.

Fixes: 70f92521 ("RDMA/hns: Use the reserved loopback QPs to free MR before destroying MPT")
Signed-off-by: wenglianfa <wenglianfa@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240906093444.3571619-3-huangjunxian6@hisilicon.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -2972,6 +2972,9 @@ static int hns_roce_v2_init(struct hns_roce_dev *hr_dev)
 
 static void hns_roce_v2_exit(struct hns_roce_dev *hr_dev)
 {
+	if (hr_dev->pci_dev->revision == PCI_REVISION_ID_HIP08)
+		free_mr_exit(hr_dev);
+
 	hns_roce_function_clear(hr_dev);
 
 	if (!hr_dev->is_vf)
@@ -6951,9 +6954,6 @@ static void __hns_roce_hw_v2_uninit_instance(struct hnae3_handle *handle,
 	hr_dev->state = HNS_ROCE_DEVICE_STATE_UNINIT;
 	hns_roce_handle_device_err(hr_dev);
 
-	if (hr_dev->pci_dev->revision == PCI_REVISION_ID_HIP08)
-		free_mr_exit(hr_dev);
-
 	hns_roce_exit(hr_dev);
 	kfree(hr_dev->priv);
 	ib_dealloc_device(&hr_dev->ib_dev);