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authorCong Wang <xiyou.wangcong@gmail.com>2017-11-07 00:47:19 +0300
committerDavid S. Miller <davem@davemloft.net>2017-11-09 04:03:09 +0300
commite4b95c41df36befcfd117210900cd790bc2cd048 (patch)
tree53d51109b9ec8ebc29f14fc9689671cda519556a /net/sched/cls_api.c
parentc7e460ce55724d4e4e22d3126e5c47273819c53a (diff)
downloadlinux-e4b95c41df36befcfd117210900cd790bc2cd048.tar.xz
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/sched/cls_api.c')
-rw-r--r--net/sched/cls_api.c1
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]) ||