queue-4.20/net-hns3-add-dma_rmb-for-rx-description.patch

   1 From foo@baz Thu Mar 14 23:20:15 PDT 2019
   2 From: Jian Shen <shenjian15@huawei.com>
   3 Date: Wed, 6 Mar 2019 11:26:37 +0800
   4 Subject: net: hns3: add dma_rmb() for rx description
   5
   6 From: Jian Shen <shenjian15@huawei.com>
   7
   8 [ Upstream commit d394d33bee22421b39a0bcdc51ca6d68ba308625 ]
   9
  10 HW can not guarantee complete write desc->rx.size, even though
  11 HNS3_RXD_VLD_B has been set. Driver needs to add dma_rmb()
  12 instruction to make sure desc->rx.size is always valid.
  13
  14 Fixes: e55970950556 ("net: hns3: Add handling of GRO Pkts not fully RX'ed in NAPI poll")
  15 Signed-off-by: Jian Shen <shenjian15@huawei.com>
  16 Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  drivers/net/ethernet/hisilicon/hns3/hns3_enet.c |    3 +++
  21  1 file changed, 3 insertions(+)
  22
  23 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
  24 +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
  25 @@ -2373,6 +2373,9 @@ static int hns3_handle_rx_bd(struct hns3
  26         length = le16_to_cpu(desc->rx.size);
  27         bd_base_info = le32_to_cpu(desc->rx.bd_base_info);
  28
  29 +       /* make sure HW write desc complete */
  30 +       dma_rmb();
  31 +
  32         /* Check valid BD */
  33         if (unlikely(!hnae3_get_bit(bd_base_info, HNS3_RXD_VLD_B)))
  34                 return -EFAULT;