From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Tue, 21 Jul 2020 19:03:53 +0800
Subject: net: hns3: fix error handling for desc filling
Patch-mainline: v5.8-rc7
Git-commit: 8ceca59fb3ed48a693171bd571c4fcbd555b7f1f
References: bsc#1104353 FATE#326415

The content of the TX desc is automatically cleared by the HW
when the HW has sent out the packet to the wire. When desc filling
fails in hns3_nic_net_xmit(), it will call hns3_clear_desc() to do
the error handling, which miss zeroing of the TX desc and the
checking if a unmapping is needed.

So add the zeroing and checking in hns3_clear_desc() to avoid the
above problem. Also add DESC_TYPE_UNKNOWN to indicate the info in
desc_cb is not valid, because hns3_nic_reclaim_desc() may treat
the desc_cb->type of zero as packet and add to the sent pkt
statistics accordingly.

Fixes: 76ad4f0ee747 ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/hisilicon/hns3/hnae3.h     |    1 +
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c |    8 ++++++++
 2 files changed, 9 insertions(+)

--- a/drivers/net/ethernet/hisilicon/hns3/hnae3.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
@@ -77,6 +77,7 @@
 	((ring)->p = ((ring)->p - 1 + (ring)->desc_num) % (ring)->desc_num)
 
 enum hns_desc_type {
+	DESC_TYPE_UNKNOWN,
 	DESC_TYPE_SKB,
 	DESC_TYPE_PAGE,
 };
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -1259,6 +1259,10 @@ static void hns3_clear_desc(struct hns3_
 	unsigned int i;
 
 	for (i = 0; i < ring->desc_num; i++) {
+		struct hns3_desc *desc = &ring->desc[ring->next_to_use];
+
+		memset(desc, 0, sizeof(*desc));
+
 		/* check if this is where we started */
 		if (ring->next_to_use == next_to_use_orig)
 			break;
@@ -1266,6 +1270,9 @@ static void hns3_clear_desc(struct hns3_
 		/* rollback one */
 		ring_ptr_move_bw(ring, next_to_use);
 
+		if (!ring->desc_cb[ring->next_to_use].dma)
+			continue;
+
 		/* unmap the descriptor dma address */
 		if (ring->desc_cb[ring->next_to_use].type == DESC_TYPE_SKB)
 			dma_unmap_single(dev,
@@ -1280,6 +1287,7 @@ static void hns3_clear_desc(struct hns3_
 
 		ring->desc_cb[ring->next_to_use].length = 0;
 		ring->desc_cb[ring->next_to_use].dma = 0;
+		ring->desc_cb[ring->next_to_use].type = DESC_TYPE_UNKNOWN;
 	}
 }