Re: [PATCH net-next] net: filter: rename 'struct sk_filter' to 'struct bpf_prog'

Willem de Bruijn
2014-07-25T18:32:53Z

>> 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.