Re: [PATCH net] net: hns3: fix wrong use of rss size during VF rss config

[Alexander Duyck <alexander.duyck@gmail.com>]

On Wed, Jan 11, 2023 at 6:56 PM Hao Lan <lanhao@huawei.com> wrote:
>
>
>
> On 2023/1/12 0:31, Alexander H Duyck wrote:
> > On Tue, 2023-01-10 at 19:53 +0800, Hao Lan wrote:
> >> From: Jie Wang <wangjie125@huawei.com>
> >>
> >> Currently, it used old rss size to get current tc mode. As a result, the
> >> rss size is updated, but the tc mode is still configured based on the old
> >> rss size.
> >>
> >> So this patch fixes it by using the new rss size in both process.
> >>
> >> Fixes: 93969dc14fcd ("net: hns3: refactor VF rss init APIs with new common rss init APIs")
> >> Signed-off-by: Jie Wang <wangjie125@huawei.com>
> >> Signed-off-by: Hao Lan <lanhao@huawei.com>
> >> ---
> >>  drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c b/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c
> >> index 081bd2c3f289..e84e5be8e59e 100644
> >> --- a/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c
> >> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c
> >> @@ -3130,7 +3130,7 @@ static int hclgevf_set_channels(struct hnae3_handle *handle, u32 new_tqps_num,
> >>
> >>      hclgevf_update_rss_size(handle, new_tqps_num);
> >>
> >> -    hclge_comm_get_rss_tc_info(cur_rss_size, hdev->hw_tc_map,
> >> +    hclge_comm_get_rss_tc_info(kinfo->rss_size, hdev->hw_tc_map,
> >>                                 tc_offset, tc_valid, tc_size);
> >>      ret = hclge_comm_set_rss_tc_mode(&hdev->hw.hw, tc_offset,
> >>                                       tc_valid, tc_size);
> >
> > I can see how this was confused. It isn't really clear that handle is
> > being used to update the kinfo->rss_size value. Maybe think about
> > adding a comment to prevent someone from reverting this without
> > realizing that? It might also be useful to do a follow-on patch for
> > net-next that renames cur_rss_size to orig_rss_size to make it more
> > obvious that the value is changing.
> >
> > Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
> > .
> >
> Hi Alexander Duyck,
> Thank you for your reviewed.And thank you for your valuable advice.
> Would it be better if we changed it to the following.
>
> -       u16 cur_rss_size = kinfo->rss_size;
> -       u16 cur_tqps = kinfo->num_tqps;
> +       u16 orig_rss_size = kinfo->rss_size;
> +       u16 orig_tqps = kinfo->num_tqps;
>         u32 *rss_indir;
>         unsigned int i;
>         int ret;
>
>         hclgevf_update_rss_size(handle, new_tqps_num);
>
> -       hclge_comm_get_rss_tc_info(cur_rss_size, hdev->hw_tc_map,
> +       /* RSS size will be updated after hclgevf_update_rss_size,
> +        * so we use kinfo->rss_size instead of orig_rss_size.
> +        */
> +       hclge_comm_get_rss_tc_info(kinfo->rss_size, hdev->hw_tc_map,

Yes, something like this would make it more obvious that these fields
are changing.