Re: [PATCH net-next v2 1/4] net/sched: act_pedit: use extack in 'ex' parsing errors

[Simon Horman <simon.horman@corigine.com>]

On Tue, Mar 14, 2023 at 05:24:45PM -0300, Pedro Tammela wrote:
> We have extack available when parsing 'ex' keys, so pass it to
> tcf_pedit_keys_ex_parse and add more detailed error messages.
> While at it, remove redundant code from the 'err_out' label code path.
> 
> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
> Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
> ---
>  net/sched/act_pedit.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 4559a1507ea5..be9e7e565551 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -35,7 +35,7 @@ static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
>  };
>  
>  static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
> -							u8 n)
> +							u8 n, struct netlink_ext_ack *extack)
>  {
>  	struct tcf_pedit_key_ex *keys_ex;
>  	struct tcf_pedit_key_ex *k;
> @@ -56,25 +56,25 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
>  		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
>  
>  		if (!n) {
> -			err = -EINVAL;
> +			NL_SET_ERR_MSG_MOD(extack, "Can't parse more extended keys than requested");
>  			goto err_out;
>  		}
> +
>  		n--;
>  
>  		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
> -			err = -EINVAL;
> +			NL_SET_ERR_MSG_MOD(extack, "Unknown attribute, expected extended key");
>  			goto err_out;
>  		}
>  
> -		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
> -						  ka, pedit_key_ex_policy,
> -						  NULL);
> +		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX, ka,
> +						  pedit_key_ex_policy, extack);
>  		if (err)
>  			goto err_out;

err_out will return ERR_PTR(-EINVAL).
I.e. the value of is not propagated.
Are you sure it is always -EINVAL?

>  
>  		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
>  		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
> -			err = -EINVAL;
> +			NL_SET_ERR_MSG_MOD(extack, "Extended Pedit missing required attributes");
>  			goto err_out;
>  		}
>  
> @@ -83,7 +83,7 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
>  
>  		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
>  		    k->cmd > TCA_PEDIT_CMD_MAX) {
> -			err = -EINVAL;
> +			NL_SET_ERR_MSG_MOD(extack, "Extended Pedit key is malformed");
>  			goto err_out;
>  		}
>  
> @@ -91,7 +91,7 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
>  	}
>  
>  	if (n) {
> -		err = -EINVAL;
> +		NL_SET_ERR_MSG_MOD(extack, "Not enough extended keys to parse");
>  		goto err_out;
>  	}
>  
> @@ -99,7 +99,7 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
>  
>  err_out:
>  	kfree(keys_ex);
> -	return ERR_PTR(err);
> +	return ERR_PTR(-EINVAL);
>  }
>  
>  static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
> @@ -222,7 +222,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
>  	}
>  
>  	nparms->tcfp_keys_ex =
> -		tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
> +		tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys, extack);
>  	if (IS_ERR(nparms->tcfp_keys_ex)) {
>  		ret = PTR_ERR(nparms->tcfp_keys_ex);
>  		goto out_free;
> -- 
> 2.34.1
>