RE: [PATCH v2 1/7] vdpa: fix improper error message when adding vdpa dev

[Parav Pandit]

> From: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> Sent: Tuesday, January 31, 2023 6:22 PM
> 
> In below example, before the fix, mtu attribute is supported by the parent
> mgmtdev, but the error message showing "All provided are not supported" is
> just misleading.
> 
> $ vdpa mgmtdev show
> vdpasim_net:
>   supported_classes net
>   max_supported_vqs 3
>   dev_features MTU MAC CTRL_VQ CTRL_MAC_ADDR ANY_LAYOUT VERSION_1
> ACCESS_PLATFORM
> 
> $ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
> Error: vdpa: All provided attributes are not supported.
> kernel answers: Operation not supported
> 
> After fix, the relevant error message will be like:
> 
> $ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
> Error: vdpa: Some provided attributes are not supported: 0x1000.
> kernel answers: Operation not supported
> 
> Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
Please add fixes tag so that older kernel gets this fix.
With that change,
Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>

> ---
>  drivers/vdpa/vdpa.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index 8ef7aa1..3a82ca78
> 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -622,9 +622,11 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct
> sk_buff *skb, struct genl_info *i
>  		err = PTR_ERR(mdev);
>  		goto err;
>  	}
> +
>  	if ((config.mask & mdev->config_attr_mask) != config.mask) {
> -		NL_SET_ERR_MSG_MOD(info->extack,
> -				   "All provided attributes are not supported");
> +		NL_SET_ERR_MSG_FMT_MOD(info->extack,
> +				       "Some provided attributes are not
> supported: 0x%llx",
> +				       config.mask & ~mdev->config_attr_mask);
>  		err = -EOPNOTSUPP;
>  		goto err;
>  	}
> --
> 1.8.3.1