On Fri, Jul 25, 2014 at 11:32 AM, Willem de Bruijn <willemb@xxxxxxxxxx> wrote: >>> This follows a convention in include/uapi/linux/netfilter/*.h that >>> likely predates the introduction of uapi. A search for "Used >>> internally by the kernel" shows many more examples. I should not have >>> included filter.h, however. The common behavior when using pointers >>> to kernel-internal structures is to have a forward declaration. I suggest >>> making that change, instead of changing to void *. This avoids having >>> to add casts where xt_bpf_info is used in net/netfilter/xt_bpf.c: >> >> that will not avoid typecast. >> Either 'void *' approach or extra 'struct sk_filter;' approach, both need >> type casts to 'struct bpf_prog' in xt_bpf.c >> (because of SK_RUN_FILTER macro) >> Therefore I prefer extra 'struct sk_filter;' approach. > > I hadn't noticed that your patch makes the same change that I > proposed. Nothing in userspace should touch that pointer, so it is > fine to change its type to struct bpf_prog* at the same time. No need > for typecasts. really? I don't think it's a good idea to expose kernel struct type to user space. How is it even going to compile? #include <linux/filter.h> brings different files in kernel and in user space. struct bpf_prog is undefined in user space and compiler will complain. Adding 'struct bpf_prog;' will be ugly. imo the lesser evil is adding 'struct sk_filter;' and doing type casts in kernel. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
