Re: [PATCH v2 net-next] net: drop_monitor: support drop reason

[Jakub Kicinski]

On Wed, 26 Jan 2022 15:23:06 +0800 menglong8.dong@xxxxxxxxx wrote:
> @@ -606,12 +610,17 @@ static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
>  static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
>  				     size_t payload_len)
>  {
> -	u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
> +	struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
>  	char buf[NET_DM_MAX_SYMBOL_LEN];
> +	enum skb_drop_reason reason;
>  	struct nlattr *attr;
>  	void *hdr;
> +	u64 pc;
>  	int rc;
>  
> +	pc = (u64)(uintptr_t)cb->pc;
> +	reason = cb->reason;
> +
>  	hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
>  			  NET_DM_CMD_PACKET_ALERT);
>  	if (!hdr)
> @@ -623,6 +632,9 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
>  	if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
>  		goto nla_put_failure;
>  
> +	if (nla_put_u32(msg, NET_DM_ATTR_REASON, reason))

Why the temporary variable instead of referring to cb->reason directly?

> +		goto nla_put_failure;