net_sched: convert tcf_hashinfo to hlist and use spinlock
So that we don't need to play with singly linked list,
and since the code is not on hot path, we can use spinlock
instead of rwlock.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 125673d..dc457c9 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -29,25 +29,16 @@
void tcf_hash_destroy(struct tcf_common *p, struct tcf_hashinfo *hinfo)
{
- unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask);
- struct tcf_common **p1p;
-
- for (p1p = &hinfo->htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
- if (*p1p == p) {
- write_lock_bh(&hinfo->lock);
- *p1p = p->tcfc_next;
- write_unlock_bh(&hinfo->lock);
- gen_kill_estimator(&p->tcfc_bstats,
- &p->tcfc_rate_est);
- /*
- * gen_estimator est_timer() might access p->tcfc_lock
- * or bstats, wait a RCU grace period before freeing p
- */
- kfree_rcu(p, tcfc_rcu);
- return;
- }
- }
- WARN_ON(1);
+ spin_lock_bh(&hinfo->lock);
+ hlist_del(&p->tcfc_head);
+ spin_unlock_bh(&hinfo->lock);
+ gen_kill_estimator(&p->tcfc_bstats,
+ &p->tcfc_rate_est);
+ /*
+ * gen_estimator est_timer() might access p->tcfc_lock
+ * or bstats, wait a RCU grace period before freeing p
+ */
+ kfree_rcu(p, tcfc_rcu);
}
EXPORT_SYMBOL(tcf_hash_destroy);
@@ -73,18 +64,19 @@
static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
struct tc_action *a, struct tcf_hashinfo *hinfo)
{
+ struct hlist_head *head;
struct tcf_common *p;
int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
struct nlattr *nest;
- read_lock_bh(&hinfo->lock);
+ spin_lock_bh(&hinfo->lock);
s_i = cb->args[0];
for (i = 0; i < (hinfo->hmask + 1); i++) {
- p = hinfo->htab[tcf_hash(i, hinfo->hmask)];
+ head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];
- for (; p; p = p->tcfc_next) {
+ hlist_for_each_entry_rcu(p, head, tcfc_head) {
index++;
if (index < s_i)
continue;
@@ -107,7 +99,7 @@
}
}
done:
- read_unlock_bh(&hinfo->lock);
+ spin_unlock_bh(&hinfo->lock);
if (n_i)
cb->args[0] += n_i;
return n_i;
@@ -120,7 +112,9 @@
static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
struct tcf_hashinfo *hinfo)
{
- struct tcf_common *p, *s_p;
+ struct hlist_head *head;
+ struct hlist_node *n;
+ struct tcf_common *p;
struct nlattr *nest;
int i = 0, n_i = 0;
@@ -130,14 +124,11 @@
if (nla_put_string(skb, TCA_KIND, a->ops->kind))
goto nla_put_failure;
for (i = 0; i < (hinfo->hmask + 1); i++) {
- p = hinfo->htab[tcf_hash(i, hinfo->hmask)];
-
- while (p != NULL) {
- s_p = p->tcfc_next;
+ head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];
+ hlist_for_each_entry_safe(p, n, head, tcfc_head) {
if (ACT_P_DELETED == tcf_hash_release(p, 0, hinfo))
module_put(a->ops->owner);
n_i++;
- p = s_p;
}
}
if (nla_put_u32(skb, TCA_FCNT, n_i))
@@ -168,15 +159,15 @@
struct tcf_common *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo)
{
- struct tcf_common *p;
+ struct tcf_common *p = NULL;
+ struct hlist_head *head;
- read_lock_bh(&hinfo->lock);
- for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p;
- p = p->tcfc_next) {
+ spin_lock_bh(&hinfo->lock);
+ head = &hinfo->htab[tcf_hash(index, hinfo->hmask)];
+ hlist_for_each_entry_rcu(p, head, tcfc_head)
if (p->tcfc_index == index)
break;
- }
- read_unlock_bh(&hinfo->lock);
+ spin_unlock_bh(&hinfo->lock);
return p;
}
@@ -236,6 +227,7 @@
p->tcfc_bindcnt = 1;
spin_lock_init(&p->tcfc_lock);
+ INIT_HLIST_NODE(&p->tcfc_head);
p->tcfc_index = index ? index : tcf_hash_new_index(idx_gen, hinfo);
p->tcfc_tm.install = jiffies;
p->tcfc_tm.lastuse = jiffies;
@@ -257,10 +249,9 @@
{
unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask);
- write_lock_bh(&hinfo->lock);
- p->tcfc_next = hinfo->htab[h];
- hinfo->htab[h] = p;
- write_unlock_bh(&hinfo->lock);
+ spin_lock_bh(&hinfo->lock);
+ hlist_add_head(&p->tcfc_head, &hinfo->htab[h]);
+ spin_unlock_bh(&hinfo->lock);
}
EXPORT_SYMBOL(tcf_hash_insert);