From: Alexei Starovoitov <alexei.starovoitov@gmail•com>
To: David Ahern <dsa@cumulusnetworks•com>
Cc: netdev@vger•kernel.org, daniel@zonque•org, ast@fb•com,
daniel@iogearbox•net, maheshb@google•com, tgraf@suug•ch
Subject: Re: [PATCH net-next v3 1/3] bpf: Refactor cgroups code in prep for new type
Date: Mon, 28 Nov 2016 12:06:43 -0800 [thread overview]
Message-ID: <20161128200641.GA7634@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <1480348130-31354-2-git-send-email-dsa@cumulusnetworks.com>
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 <dsa@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.
next prev parent reply other threads:[~2016-11-28 20:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-28 15:48 [PATCH net-next v3 0/3] net: Add bpf support to set sk_bound_dev_if David Ahern
2016-11-28 15:48 ` [PATCH net-next v3 1/3] bpf: Refactor cgroups code in prep for new type David Ahern
2016-11-28 20:06 ` Alexei Starovoitov [this message]
2016-11-28 20:31 ` David Ahern
2016-11-28 15:48 ` [PATCH net-next v3 2/3] bpf: Add new cgroup attach type to enable sock modifications David Ahern
2016-11-28 20:32 ` Alexei Starovoitov
2016-11-28 20:57 ` David Ahern
2016-11-28 15:48 ` [PATCH net-next v3 3/3] samples: bpf: add userspace example for modifying sk_bound_dev_if David Ahern
2016-11-28 20:37 ` Alexei Starovoitov
2016-11-28 20:47 ` David Ahern
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