@@ -38,7 +38,6 @@ struct tc_action {
struct gnet_stats_queue tcfa_qstats;
struct net_rate_estimator __rcu *tcfa_rate_est;
spinlock_t tcfa_lock;
- struct rcu_head tcfa_rcu;
struct gnet_stats_basic_cpu __percpu *cpu_bstats;
struct gnet_stats_queue __percpu *cpu_qstats;
struct tc_cookie *act_cookie;
@@ -55,7 +54,6 @@ struct tc_action {
#define tcf_qstats common.tcfa_qstats
#define tcf_rate_est common.tcfa_rate_est
#define tcf_lock common.tcfa_lock
-#define tcf_rcu common.tcfa_rcu
static inline unsigned int tcf_hash(u32 index, unsigned int hmask)
{
@@ -53,10 +53,8 @@ static void tcf_action_goto_chain_exec(const struct tc_action *a,
res->goto_tp = rcu_dereference_bh(chain->filter_chain);
}
-static void free_tcf(struct rcu_head *head)
+static void free_tcf(struct tc_action *p)
{
- struct tc_action *p = container_of(head, struct tc_action, tcfa_rcu);
-
free_percpu(p->cpu_bstats);
free_percpu(p->cpu_qstats);
@@ -76,11 +74,7 @@ static void tcf_hash_destroy(struct tcf_hashinfo *hinfo, struct tc_action *p)
hlist_del(&p->tcfa_head);
spin_unlock_bh(&hinfo->lock);
gen_kill_estimator(&p->tcfa_rate_est);
- /*
- * gen_estimator est_timer() might access p->tcfa_lock
- * or bstats, wait a RCU grace period before freeing p
- */
- call_rcu(&p->tcfa_rcu, free_tcf);
+ free_tcf(p);
}
int __tcf_hash_release(struct tc_action *p, bool bind, bool strict)
@@ -271,7 +265,7 @@ void tcf_hash_cleanup(struct tc_action *a, struct nlattr *est)
{
if (est)
gen_kill_estimator(&a->tcfa_rate_est);
- call_rcu(&a->tcfa_rcu, free_tcf);
+ free_tcf(a);
}
EXPORT_SYMBOL(tcf_hash_cleanup);
gen estimator has been rewritten in commit 1c0d32fde5bd ("net_sched: gen_estimator: complete rewrite of rate estimators"), the caller is no longer needed to wait for a grace period. So this patch gets rid of it. This also completely closes a race condition between action free path and filter chain add/remove path for the following patch. Because otherwise the nested RCU callback can't be caught by rcu_barrier(). Cc: Jiri Pirko <jiri@mellanox.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- include/net/act_api.h | 2 -- net/sched/act_api.c | 12 +++--------- 2 files changed, 3 insertions(+), 11 deletions(-)