linux_dsm_epyc7002/include/net/tc_act/tc_bpf.h
Alexei Starovoitov cff82457c5 net_sched: act_bpf: remove spinlock in fast path
Similar to act_gact/act_mirred, act_bpf can be lockless in packet processing
with extra care taken to free bpf programs after rcu grace period.
Replacement of existing act_bpf (very rare) is done with synchronize_rcu()
and final destruction is done from tc_action_ops->cleanup() callback that is
called from tcf_exts_destroy()->tcf_action_destroy()->__tcf_hash_release() when
bind and refcnt reach zero which is only possible when classifier is destroyed.
Previous two patches fixed the last two classifiers (tcindex and rsvp) to
call tcf_exts_destroy() from rcu callback.

Similar to gact/mirred there is a race between prog->filter and
prog->tcf_action. Meaning that the program being replaced may use
previous default action if it happened to return TC_ACT_UNSPEC.
act_mirred race betwen tcf_action and tcfm_dev is similar.
In all cases the race is harmless.
Long term we may want to improve the situation by replacing the whole
tc_action->priv as single pointer instead of updating inner fields one by one.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26 11:01:45 -07:00

30 lines
691 B
C

/*
* Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __NET_TC_BPF_H
#define __NET_TC_BPF_H
#include <linux/filter.h>
#include <net/act_api.h>
struct tcf_bpf {
struct tcf_common common;
struct bpf_prog __rcu *filter;
union {
u32 bpf_fd;
u16 bpf_num_ops;
};
struct sock_filter *bpf_ops;
const char *bpf_name;
};
#define to_bpf(a) \
container_of(a->priv, struct tcf_bpf, common)
#endif /* __NET_TC_BPF_H */