From: Huazhong Tan <tanhuazhong@huawei.com>
Date: Wed, 1 Aug 2018 18:27:03 +0800
Subject: net: hns3: fix return value error while hclge_cmd_csq_clean failed
Patch-mainline: v4.19-rc1
Git-commit: 4a62e252e888f67cb87caf36f48338889b0b8a43
References: bsc#1104353 FATE#326415

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c
@@ -161,7 +161,12 @@ static int hclge_cmd_csq_clean(struct hc
 	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;
@@ -283,10 +288,11 @@ int hclge_cmd_send(struct hclge_hw *hw,
 
 	/* 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);