APPLIED(B,C): [PATCH][SRU Bionic] net: hns3: add dma_rmb() for rx description

[Khaled Elmously]

On 2019-03-20 12:51:34 , dann frazier wrote:
> From: Jian Shen <shenjian15 at huawei.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1821064
> 
> 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 at huawei.com>
> Signed-off-by: Huazhong Tan <tanhuazhong at huawei.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (backported from commit d394d33bee22421b39a0bcdc51ca6d68ba308625)
> [ dannf: trivial context fix ]
> Signed-off-by: dann frazier <dann.frazier at canonical.com>
> ---
>  drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> index 15d9de4c0575a..08718f9093dc5 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> @@ -2466,6 +2466,8 @@ static int hns3_add_frag(struct hns3_enet_ring *ring, struct hns3_desc *desc,
>  		desc = &ring->desc[ring->next_to_clean];
>  		desc_cb = &ring->desc_cb[ring->next_to_clean];
>  		bd_base_info = le32_to_cpu(desc->rx.bd_base_info);
> +		/* make sure HW write desc complete */
> +		dma_rmb();
>  		if (!hnae3_get_bit(bd_base_info, HNS3_RXD_VLD_B))
>  			return -ENXIO;
>  
> -- 
> 2.20.1
> 
> 
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