Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760861AbaGYSnJ (ORCPT ); Fri, 25 Jul 2014 14:43:09 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:33600 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759699AbaGYSnG (ORCPT ); Fri, 25 Jul 2014 14:43:06 -0400 MIME-Version: 1.0 In-Reply-To: References: <1406275499-7822-1-git-send-email-ast@plumgrid.com> <53D23EAF.4000001@redhat.com> <20140725115414.GA4770@salvia> Date: Fri, 25 Jul 2014 11:43:05 -0700 Message-ID: Subject: Re: [PATCH net-next] net: filter: rename 'struct sk_filter' to 'struct bpf_prog' From: Alexei Starovoitov To: Willem de Bruijn Cc: Pablo Neira Ayuso , Daniel Borkmann , "David S. Miller" , Network Development , linux-kernel , netfilter-devel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 25, 2014 at 11:32 AM, Willem de Bruijn 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 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 linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/