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Date: Thu, 12 Dec 2013 21:47:53 -0800
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: Cong Wang <xiyou.wangcong@...il.com>,
Jamal Hadi Salim <jhs@...atatu.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH net-next v3 6/6] net_sched: convert tcf_hashinfo to hlist and use rcu
So that we don't need to play with singly linked list
and of course we can use RCU+spinlock instead of rwlock
now.
Cc: Jamal Hadi Salim <jhs@...atatu.com>
Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
include/net/act_api.h | 16 +++++++-----
net/sched/act_api.c | 71 +++++++++++++++++++++++---------------------------
net/sched/act_police.c | 47 ++++++++++++++-------------------
3 files changed, 62 insertions(+), 72 deletions(-)
diff --git a/include/net/act_api.h b/include/net/act_api.h
index 2678b67..18af68e 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -9,7 +9,7 @@
#include <net/pkt_sched.h>
struct tcf_common {
- struct tcf_common *tcfc_next;
+ struct hlist_node tcfc_head;
u32 tcfc_index;
int tcfc_refcnt;
int tcfc_bindcnt;
@@ -22,7 +22,7 @@ struct tcf_common {
spinlock_t tcfc_lock;
struct rcu_head tcfc_rcu;
};
-#define tcf_next common.tcfc_next
+#define tcf_head common.tcfc_head
#define tcf_index common.tcfc_index
#define tcf_refcnt common.tcfc_refcnt
#define tcf_bindcnt common.tcfc_bindcnt
@@ -36,9 +36,9 @@ struct tcf_common {
#define tcf_rcu common.tcfc_rcu
struct tcf_hashinfo {
- struct tcf_common **htab;
+ struct hlist_head *htab;
unsigned int hmask;
- rwlock_t lock;
+ spinlock_t lock;
};
static inline unsigned int tcf_hash(u32 index, unsigned int hmask)
@@ -48,12 +48,16 @@ static inline unsigned int tcf_hash(u32 index, unsigned int hmask)
static inline int tcf_hashinfo_init(struct tcf_hashinfo *hf, unsigned int mask)
{
- rwlock_init(&hf->lock);
+ int i;
+
+ spin_lock_init(&hf->lock);
hf->hmask = mask;
- hf->htab = kzalloc((mask + 1) * sizeof(struct tcf_common *),
+ hf->htab = kzalloc((mask + 1) * sizeof(struct hlist_head),
GFP_KERNEL);
if (!hf->htab)
return -ENOMEM;
+ for (i = 0; i < mask + 1; i++)
+ INIT_HLIST_HEAD(&hf->htab[i]);
return 0;
}
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 2641a8b..974e8f7 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -29,25 +29,17 @@
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_rcu(&p->tcfc_head);
+ spin_unlock_bh(&hinfo->lock);
+ synchronize_rcu();
+ 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 +65,19 @@ EXPORT_SYMBOL(tcf_hash_release);
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);
+ rcu_read_lock_bh();
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 +100,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
}
}
done:
- read_unlock_bh(&hinfo->lock);
+ rcu_read_unlock_bh();
if (n_i)
cb->args[0] += n_i;
return n_i;
@@ -120,7 +113,9 @@ nla_put_failure:
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 +125,11 @@ static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
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 +160,15 @@ EXPORT_SYMBOL(tcf_generic_walker);
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) {
+ rcu_read_lock_bh();
+ 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);
+ rcu_read_unlock_bh();
return p;
}
@@ -236,6 +228,7 @@ struct tcf_common *tcf_hash_create(u32 index, struct nlattr *est,
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 +250,10 @@ void tcf_hash_insert(struct tcf_common *p, struct tcf_hashinfo *hinfo)
{
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_rcu(&p->tcfc_head, &hinfo->htab[h]);
+ spin_unlock_bh(&hinfo->lock);
+ synchronize_rcu();
}
EXPORT_SYMBOL(tcf_hash_insert);
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index f201576..26dffca 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -60,18 +60,19 @@ struct tc_police_compat {
static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb,
int type, struct tc_action *a)
{
+ 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(&police_hash_info.lock);
+ rcu_read_lock_bh();
s_i = cb->args[0];
for (i = 0; i < (POL_TAB_MASK + 1); i++) {
- p = police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)];
+ head = &police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)];
- for (; p; p = p->tcfc_next) {
+ hlist_for_each_entry_rcu(p, head, tcfc_head) {
index++;
if (index < s_i)
continue;
@@ -94,7 +95,7 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c
}
}
done:
- read_unlock_bh(&police_hash_info.lock);
+ rcu_read_unlock_bh();
if (n_i)
cb->args[0] += n_i;
return n_i;
@@ -106,25 +107,17 @@ nla_put_failure:
static void tcf_police_destroy(struct tcf_police *p)
{
- unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK);
- struct tcf_common **p1p;
-
- for (p1p = &police_hash_info.htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
- if (*p1p == &p->common) {
- write_lock_bh(&police_hash_info.lock);
- *p1p = p->tcf_next;
- write_unlock_bh(&police_hash_info.lock);
- gen_kill_estimator(&p->tcf_bstats,
- &p->tcf_rate_est);
- /*
- * gen_estimator est_timer() might access p->tcf_lock
- * or bstats, wait a RCU grace period before freeing p
- */
- kfree_rcu(p, tcf_rcu);
- return;
- }
- }
- WARN_ON(1);
+ spin_lock_bh(&police_hash_info.lock);
+ hlist_del_rcu(&p->tcf_head);
+ spin_unlock_bh(&police_hash_info.lock);
+ synchronize_rcu();
+ gen_kill_estimator(&p->tcf_bstats,
+ &p->tcf_rate_est);
+ /*
+ * gen_estimator est_timer() might access p->tcf_lock
+ * or bstats, wait a RCU grace period before freeing p
+ */
+ kfree_rcu(p, tcf_rcu);
}
static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
@@ -259,10 +252,10 @@ override:
police->tcf_index = parm->index ? parm->index :
tcf_hash_new_index(&police_idx_gen, &police_hash_info);
h = tcf_hash(police->tcf_index, POL_TAB_MASK);
- write_lock_bh(&police_hash_info.lock);
- police->tcf_next = police_hash_info.htab[h];
- police_hash_info.htab[h] = &police->common;
- write_unlock_bh(&police_hash_info.lock);
+ spin_lock_bh(&police_hash_info.lock);
+ hlist_add_head_rcu(&police->tcf_head, &police_hash_info.htab[h]);
+ spin_unlock_bh(&police_hash_info.lock);
+ synchronize_rcu();
a->priv = police;
return ret;
--
1.8.1.4
--
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