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author | Cong Wang <xiyou.wangcong@gmail.com> | 2017-11-06 13:47:19 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-11-09 10:03:09 +0900 |
commit | e4b95c41df36befcfd117210900cd790bc2cd048 (patch) | |
tree | 53d51109b9ec8ebc29f14fc9689671cda519556a /net | |
parent | c7e460ce55724d4e4e22d3126e5c47273819c53a (diff) | |
download | linux-stable-e4b95c41df36befcfd117210900cd790bc2cd048.tar.gz linux-stable-e4b95c41df36befcfd117210900cd790bc2cd048.tar.bz2 linux-stable-e4b95c41df36befcfd117210900cd790bc2cd048.zip |
net_sched: introduce tcf_exts_get_net() and tcf_exts_put_net()
Instead of holding netns refcnt in tc actions, we can minimize
the holding time by saving it in struct tcf_exts instead. This
means we can just hold netns refcnt right before call_rcu() and
release it after tcf_exts_destroy() is done.
However, because on netns cleanup path we call tcf_proto_destroy()
too, obviously we can not hold netns for a zero refcnt, in this
case we have to do cleanup synchronously. It is fine for RCU too,
the caller cleanup_net() already waits for a grace period.
For other cases, refcnt is non-zero and we can safely grab it as
normal and release it after we are done.
This patch provides two new API for each filter to use:
tcf_exts_get_net() and tcf_exts_put_net(). And all filters now can
use the following pattern:
void __destroy_filter() {
tcf_exts_destroy();
tcf_exts_put_net(); // <== release netns refcnt
kfree();
}
void some_work() {
rtnl_lock();
__destroy_filter();
rtnl_unlock();
}
void some_rcu_callback() {
tcf_queue_work(some_work);
}
if (tcf_exts_get_net()) // <== hold netns refcnt
call_rcu(some_rcu_callback);
else
__destroy_filter();
Cc: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/sched/cls_api.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index b2d310745487..ecbb019efcbd 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -927,6 +927,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, exts->actions[i++] = act; exts->nr_actions = i; } + exts->net = net; } #else if ((exts->action && tb[exts->action]) || |