From 6446be7c909045f336e6e4bd0effb427de5847ee Mon Sep 17 00:00:00 2001
From: Guangbin Huang <huangguangbin2@huawei.com>
Date: Tue, 19 Oct 2021 22:16:30 +0800
Subject: [PATCH] net: hns3: add limit ets dwrr bandwidth cannot be 0
Git-commit: 731797fdffa3d083db536e2fdd07ceb050bb40b1
Patch-mainline: v5.15-rc7
References: stable-5.14.15

[ Upstream commit 731797fdffa3d083db536e2fdd07ceb050bb40b1 ]

If ets dwrr bandwidth of tc is set to 0, the hardware will switch to SP
mode. In this case, this tc may occupy all the tx bandwidth if it has
huge traffic, so it violates the purpose of the user setting.

To fix this problem, limit the ets dwrr bandwidth must greater than 0.

Fixes: cacde272dd00 ("net: hns3: Add hclge_dcb module for the support of DCB feature")
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c
index c90bfde2aecf..c60d0626062c 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c
@@ -133,6 +133,15 @@ static int hclge_ets_validate(struct hclge_dev *hdev, struct ieee_ets *ets,
 				*changed = true;
 			break;
 		case IEEE_8021QAZ_TSA_ETS:
+			/* The hardware will switch to sp mode if bandwidth is
+			 * 0, so limit ets bandwidth must be greater than 0.
+			 */
+			if (!ets->tc_tx_bw[i]) {
+				dev_err(&hdev->pdev->dev,
+					"tc%u ets bw cannot be 0\n", i);
+				return -EINVAL;
+			}
+
 			if (hdev->tm_info.tc_info[i].tc_sch_mode !=
 				HCLGE_SCH_MODE_DWRR)
 				*changed = true;
-- 
2.26.2