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From:   Huazhong Tan <tanhuazhong@huawei.com>
To:     <davem@davemloft.net>
CC:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <salil.mehta@huawei.com>, <yisen.zhuang@huawei.com>,
        <linuxarm@huawei.com>, <kuba@kernel.org>,
        Yunsheng Lin <linyunsheng@huawei.com>,
        Huazhong Tan <tanhuazhong@huawei.com>
Subject: [PATCH net 3/4] net: hns3: fix error handling for desc filling
Date:   Tue, 21 Jul 2020 19:03:53 +0800
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From: Yunsheng Lin <linyunsheng@huawei.com>

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>
---
 drivers/net/ethernet/hisilicon/hns3/hnae3.h     | 1 +
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hnae3.h b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
index d041cac..088550d 100644
--- 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_FRAGLIST_SKB,
 	DESC_TYPE_PAGE,
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index a814d99..b1bea030 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -1338,6 +1338,10 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 	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;
@@ -1345,6 +1349,9 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 		/* 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 ||
 		    ring->desc_cb[ring->next_to_use].type ==
@@ -1361,6 +1368,7 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 
 		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;
 	}
 }
 
-- 
2.7.4