net: hns3: bugfix for handling mailbox while the command queue reinitialized

In a multi-core machine, the mailbox service and reset service
will be executed at the same time. The reset service will re-initialize
the command queue, before that, the mailbox handler can only get some
invalid messages.

The HCLGE_STATE_CMD_DISABLE flag means that the command queue is not
available and needs to be reinitialized. Therefore, when the mailbox
handler recognizes this flag, it should not process the command.

Fixes: dde1a86e93ca ("net: hns3: Add mailbox support to PF driver")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_mbx.c

@@ -400,6 +400,12 @@ void hclge_mbx_handler(struct hclge_dev *hdev)
 
 	/* handle all the mailbox requests in the queue */
 	while (!hclge_cmd_crq_empty(&hdev->hw)) {
+		if (test_bit(HCLGE_STATE_CMD_DISABLE, &hdev->state)) {
+			dev_warn(&hdev->pdev->dev,
+				 "command queue needs re-initializing\n");
+			return;
+		}
+
 		desc = &crq->desc[crq->next_to_use];
 		req = (struct hclge_mbx_vf_to_pf_cmd *)desc->data;