Re: [PATCH 9/9] netfilter: implement xt_cgroup cgroup2 path match

[Tejun Heo <tj@kernel.org>]

Hello,

On Sat, Nov 21, 2015 at 05:56:06PM +0100, Florian Westphal wrote:
> > +struct xt_cgroup_info_v1 {
> > +	__u8		has_path;
> > +	__u8		has_classid;
> > +	__u8		invert_path;
> > +	__u8		invert_classid;
> > +	char		path[PATH_MAX];
> > +	__u32		classid;
> > +
> > +	/* kernel internal data */
> > +	void		*priv __attribute__((aligned(8)));
> > +};
> 
> Ahem.  Am I reading this right? This struct is > 4k in size?
> If so -- Ugh.  Does sizeof(path) really have to be PATH_MAX?

Hmmm... yeap but would this be an acutual problem?  We can try to make
it shorter but idk it ultimately is a path.  Another solution would be
trying to pass inode around but that is problematic with showing and
printing rules as the only way to reverse-map inode to path is walking
the tree and the cgroup may already be gone at that point.  While >4k
struct isn't pretty, this looks like the path of least resistance.

Thanks.

-- 
tejun