Re: [PATCH v8 net-next] net: drop_monitor: support drop reason

[David Ahern <dsahern@gmail.com>]

On 2/8/22 10:08 PM, menglong8.dong@gmail.com wrote:
> From: Menglong Dong <imagedong@tencent.com>
> 
> In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()")
> drop reason is introduced to the tracepoint of kfree_skb. Therefore,
> drop_monitor is able to report the drop reason to users by netlink.
> 
> The drop reasons are reported as string to users, which is exactly
> the same as what we do when reporting it to ftrace.
> 
> Signed-off-by: Menglong Dong <imagedong@tencent.com>
> ---
> v8:
> - pass drop reason to net_dm_packet_report_size()
> - move drop reason validation to net_dm_packet_trace_kfree_skb_hit()
> 
> v7:
> - take the size of NET_DM_ATTR_REASON into accounting in
>   net_dm_packet_report_size()
> - let compiler define the size of drop_reasons
> 
> v6:
> - check the range of drop reason in net_dm_packet_report_fill()
> 
> v5:
> - check if drop reason larger than SKB_DROP_REASON_MAX
> 
> v4:
> - report drop reasons as string
> 
> v3:
> - referring to cb->reason and cb->pc directly in
>   net_dm_packet_report_fill()
> 
> v2:
> - get a pointer to struct net_dm_skb_cb instead of local var for
>   each field
> ---
>  include/uapi/linux/net_dropmon.h |  1 +
>  net/core/drop_monitor.c          | 41 +++++++++++++++++++++++++++-----
>  2 files changed, 36 insertions(+), 6 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>