Re: [PATCH net-next 2/3] net: ethtool: move checks before rtnl_lock() in ethnl_set_rings

[wangjie (L)]

On 2022/4/9 5:58, Jakub Kicinski wrote:
> On Fri, 8 Apr 2022 15:12:44 +0800 Guangbin Huang wrote:
> > +	if (tb[ETHTOOL_A_RINGS_RX_BUF_LEN] &&
> > +	    nla_get_u32(tb[ETHTOOL_A_RINGS_RX_BUF_LEN]) != 0 &&
>
> I think we can drop the value checking. If attribute is present and
> drivers doesn't support - reject. I don't think that would require
> any changes to existing user space but please double check.
I have checked user space code and tested the delete version on my 
server, these value checking will be dropped in v2.
> > +	    !(ops->supported_ring_params & ETHTOOL_RING_USE_RX_BUF_LEN)) {
> > +		ret = -EOPNOTSUPP;
> > +		NL_SET_ERR_MSG_ATTR(info->extack,
> > +				    tb[ETHTOOL_A_RINGS_RX_BUF_LEN],
> > +				    "setting rx buf len not supported");
> > +		goto out_dev;
> > +	}
> > +
> > +	if (tb[ETHTOOL_A_RINGS_CQE_SIZE] &&
> > +	    nla_get_u32(tb[ETHTOOL_A_RINGS_CQE_SIZE]) &&
> > +	    !(ops->supported_ring_params & ETHTOOL_RING_USE_CQE_SIZE)) {
> > +		ret = -EOPNOTSUPP;
> > +		NL_SET_ERR_MSG_ATTR(info->extack,
> > +				    tb[ETHTOOL_A_RINGS_CQE_SIZE],
> > +				    "setting cqe size not supported");
> > +		goto out_dev;
> > +	}
>
> .