net: hns3: add dma_rmb() for rx description

[ Upstream commit d394d33bee22421b39a0bcdc51ca6d68ba308625 ]

HW can not guarantee complete write desc->rx.size, even though
HNS3_RXD_VLD_B has been set. Driver needs to add dma_rmb()
instruction to make sure desc->rx.size is always valid.

Fixes: e55970950556 ("net: hns3: Add handling of GRO Pkts not fully RX'ed in NAPI poll")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index d424d5bc050790763e96f12530b794c8a7489e15..b396e934e83f8e12e8650b8fb1f4e19cdde1360a 100644 (file)
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -2373,6 +2373,9 @@ static int hns3_handle_rx_bd(struct hns3_enet_ring *ring,
        length = le16_to_cpu(desc->rx.size);
        bd_base_info = le32_to_cpu(desc->rx.bd_base_info);
 
+       /* make sure HW write desc complete */
+       dma_rmb();
+
        /* Check valid BD */
        if (unlikely(!hnae3_get_bit(bd_base_info, HNS3_RXD_VLD_B)))
                return -EFAULT;