Subject: Re: [PATCH net-next 3/8] devlink: report extended error message in region_read_dumpit

From: Jakub Kicinski <[email-masked]>
Date: Fri, 18 Nov 2022 17:40:12 -0800

On Thu, 17 Nov 2022 14:07:58 -0800 Jacob Keller wrote:
> Report extended error details in the devlink_nl_cmd_region_read_dumpit
> function, by using the extack structure from the netlink_callback.
> 
> Signed-off-by: Jacob Keller <[email-masked]>
> ---
>  net/core/devlink.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index 932476956d7e..f2ee1da5283c 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -6453,8 +6453,14 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
>  
>  	devl_lock(devlink);
>  
> -	if (!attrs[DEVLINK_ATTR_REGION_NAME] ||
> -	    !attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) {
> +	if (!attrs[DEVLINK_ATTR_REGION_NAME]) {
> +		NL_SET_ERR_MSG_MOD(cb->extack, "No region name provided");
> +		err = -EINVAL;
> +		goto out_unlock;
> +	}
> +
> +	if (!attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) {

Please use GENL_REQ_ATTR_CHECK() instead of adding strings.

> +		NL_SET_ERR_MSG_MOD(cb->extack, "No snapshot id provided");
>  		err = -EINVAL;
>  		goto out_unlock;
>  	}
> @@ -6477,6 +6483,8 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
>  		region = devlink_region_get_by_name(devlink, region_name);
>  
>  	if (!region) {
> +		NL_SET_ERR_MSG_MOD(cb->extack,
> +				   "The requested region does not exist");

NL_SET_ERR_MSG_ATTR()

>  		err = -EINVAL;
>  		goto out_unlock;
>  	}
> @@ -6484,6 +6492,8 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
>  	snapshot_id = nla_get_u32(attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
>  	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
>  	if (!snapshot) {
> +		NL_SET_ERR_MSG_MOD(cb->extack,
> +				   "The requested snapshot id does not exist");

ditto

>  		err = -EINVAL;
>  		goto out_unlock;
>  	}