Hello Dan,

Thanks for your  report!

在 2021/3/24 15:01, Dan Carpenter 写道:

Hello Jian Shen,

The patch 5f2b1238b33c: "net: hns3: refactor out hclge_add_fd_entry()" from Mar 22, 2021, leads to the following static checker warning:

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c:6512 hclge_fd_parse_ring_cookie() warn: array off by one? 'hdev->vport[vf]'

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c 6493 static int hclge_fd_parse_ring_cookie(struct hclge_dev *hdev, u64 ring_cookie, 6494 u16 *vport_id, u8 *action, u16 *queue_id) 6495 { 6496 struct hclge_vport *vport = hdev->vport; 6497 6498 if (ring_cookie == RX_CLS_FLOW_DISC) { 6499 *action = HCLGE_FD_ACTION_DROP_PACKET; 6500 } else { 6501 u32 ring = ethtool_get_flow_spec_ring(ring_cookie); 6502 u8 vf = ethtool_get_flow_spec_ring_vf(ring_cookie); 6503 u16 tqps; 6504 6505 if (vf > hdev->num_req_vfs) { ^^^^^^^^^^^^^^^^^^^^^^

The is off by one but checking hdev->num_req_vfs in this context doesn't make sense. Should it instead be check hdev->num_alloc_vport? Also should we add HCLGE_VF_VPORT_START_NUM?

vf = ethtool_get_flow_spec_ring_vf(ring_cookie);
vf += HCLGE_VF_VPORT_START_NUM;
if (vf >= hdev->num_alloc_vport)
	return -EINVAL;

6506 dev_err(&hdev->pdev->dev, 6507 "Error: vf id (%u) > max vf num (%u)\n", ^^ Use >=

6508 vf, hdev->num_req_vfs); 6509 return -EINVAL; 6510 } 6511 6512 *vport_id = vf ? hdev->vport[vf].vport_id : vport->vport_id; ^^^^^^^^^ 6513 tqps = hdev->vport[vf].nic.kinfo.num_tqps; ^^^ The vport array has hdev->num_vmdq_vport + hdev->num_req_vfs + 1; elements. ->vport[0] is tqp_main_vport. The next elements are hdev->num_vmdq_vport and the last part of the array is hdev->num_req_vfs.

Another possibility is that perhaps this is what was intended?

	idx = vf + 1 + hdev->num_vmdq_vport;

	*vport_id = vf ? vport[idx].vport_id : vport[0].vport_id;
	tqps = vport[idx].nic.kinfo.num_tqps;

There is related code that offers clues but I'm not sure what to do.

6514 6515 if (ring >= tqps) { 6516 dev_err(&hdev->pdev->dev, 6517 "Error: queue id (%u) > max tqp num (%u)\n", 6518 ring, tqps - 1); 6519 return -EINVAL; 6520 } 6521 6522 *action = HCLGE_FD_ACTION_SELECT_QUEUE; 6523 *queue_id = ring; 6524 } 6525 6526 return 0; 6527 }

[ snip ]

9111 static bool hclge_check_vf_mac_exist(struct hclge_vport *vport, int vf_idx, 9112 u8 *mac_addr) 9113 { 9114 struct hclge_mac_vlan_tbl_entry_cmd req; 9115 struct hclge_dev *hdev = vport->back; 9116 struct hclge_desc desc; 9117 u16 egress_port = 0; 9118 int i; 9119 9120 if (is_zero_ether_addr(mac_addr)) 9121 return false; 9122 9123 memset(&req, 0, sizeof(req)); 9124 hnae3_set_field(egress_port, HCLGE_MAC_EPORT_VFID_M, 9125 HCLGE_MAC_EPORT_VFID_S, vport->vport_id); 9126 req.egress_port = cpu_to_le16(egress_port); 9127 hclge_prepare_mac_addr(&req, mac_addr, false); 9128 9129 if (hclge_lookup_mac_vlan_tbl(vport, &req, &desc, false) != -ENOENT) 9130 return true; 9131 9132 vf_idx += HCLGE_VF_VPORT_START_NUM; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ We're are skipping the first element. Should it instead be?:

vf_idx += hdev->num_vmdq_vport + 1;

9133 for (i = hdev->num_vmdq_vport + 1; i < hdev->num_alloc_vport; i++) ^^^^^^^^^^^^^^^^^^^^^^^^ We're only checking the last part of the array.

9134 if (i != vf_idx && 9135 ether_addr_equal(mac_addr, hdev->vport[i].vf_info.mac)) 9136 return true; 9137 9138 return false; 9139 }

Another thing that's not clear to me is how pci_num_vf() relates to this. I suspect that it is the same as hdev->num_vmdq_vport, but I can't be sure.

regards, dan carpenter .

The use for num_vmdq_vport is confusing. At the beginning, the HNS3 driver is planed to support VMDQ . Whereafter the hardware supports SR-IOV with better performance. So VMDQ feature is discarded,  but the codes of vmdq is remained. For the value of num_vmdq_vport is always 0, so the vport id of VF is actually start from 1. That's why the driver still work.

As the num_vmdq_vport is actually useless and confusing, I will send a patch to remove it soon.

regards, Jian Shen