net: hns3: fix return value error while hclge_cmd_csq_clean failed

While cleaning the command queue, the value of the HEAD register is not
in the range of next_to_clean and next_to_use, meaning that this value
is invalid. This also means that there is a hardware error and the
hardware will trigger a reset soon. At this time we should return an
error code instead of 0, and HCLGE_STATE_CMD_DISABLE needs to be set to
prevent sending command again.

Fixes: 3ff504908f95 ("net: hns3: fix a dead loop in hclge_cmd_csq_clean")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -147,7 +147,12 @@ static int hclge_cmd_csq_clean(struct hclge_hw *hw)
 	if (!is_valid_csq_clean_head(csq, head)) {
 		dev_warn(&hdev->pdev->dev, "wrong cmd head (%d, %d-%d)\n", head,
 			 csq->next_to_use, csq->next_to_clean);
-		return 0;
+		dev_warn(&hdev->pdev->dev,
+			 "Disabling any further commands to IMP firmware\n");
+		set_bit(HCLGE_STATE_CMD_DISABLE, &hdev->state);
+		dev_warn(&hdev->pdev->dev,
+			 "IMP firmware watchdog reset soon expected!\n");
+		return -EIO;
 	}
 
 	clean = (head - csq->next_to_clean + csq->desc_num) % csq->desc_num;
@@ -267,10 +272,11 @@ int hclge_cmd_send(struct hclge_hw *hw, struct hclge_desc *desc, int num)
 
 	/* Clean the command send queue */
 	handle = hclge_cmd_csq_clean(hw);
-	if (handle != num) {
+	if (handle < 0)
+		retval = handle;
+	else if (handle != num)
 		dev_warn(&hdev->pdev->dev,
 			 "cleaned %d, need to clean %d\n", handle, num);
-	}
 
 	spin_unlock_bh(&hw->cmq.csq.lock);