On 11/28/16 1:06 PM, Alexei Starovoitov wrote:
> On Mon, Nov 28, 2016 at 07:48:48AM -0800, David Ahern wrote:
>> Code move only; no functional change intended.
>
> not quite...
>
>> Signed-off-by: David Ahern <d...@cumulusnetworks.com>
> ...
>> * @sk: The socken sending or receiving traffic
>> @@ -153,11 +166,15 @@ int __cgroup_bpf_run_filter(struct sock *sk,
>>
>> prog = rcu_dereference(cgrp->bpf.effective[type]);
>> if (prog) {
>> - unsigned int offset = skb->data - skb_network_header(skb);
>> -
>> - __skb_push(skb, offset);
>> - ret = bpf_prog_run_save_cb(prog, skb) == 1 ? 0 : -EPERM;
>> - __skb_pull(skb, offset);
>> + switch (type) {
>> + case BPF_CGROUP_INET_INGRESS:
>> + case BPF_CGROUP_INET_EGRESS:
>> + ret = __cgroup_bpf_run_filter_skb(skb, prog);
>> + break;
>
> hmm. what's a point of double jump table? It's only burning cycles
> in the fast path. We already have
> prog = rcu_dereference(cgrp->bpf.effective[type]); if (prog) {...}
> Could you do a variant of __cgroup_bpf_run_filter() instead ?
> That doesnt't take 'skb' as an argument.
> It will also solve scary looking NULL skb from patch 2:
> __cgroup_bpf_run_filter(sk, NULL, ...
>
> and to avoid copy-pasting first dozen lines of current
> __cgroup_bpf_run_filter can be moved into a helper that
> __cgroup_bpf_run_filter_skb and
> __cgroup_bpf_run_filter_sk will call.
> Or some other way to rearrange that code.
>
sure
1. rename the existing __cgroup_bpf_run_filter to __cgroup_bpf_run_filter_skb
2. create new __cgroup_bpf_run_filter_sk for this new program type. the new
run_filter does not need the family or full sock checks for this use case so
the common code is only the sock_cgroup_ptr and prog lookups.
