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Date: Thu, 31 Jan 2013 04:27:47 +0900
From: YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
To: davem@...emloft.net, netdev@...r.kernel.org
CC: yoshfuji@...ux-ipv6.org
Subject: [RFC net-next 2/4] ipv6 flowlabel: Convert hash list to RCU.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
---
include/net/ipv6.h | 1 +
net/ipv6/ip6_flowlabel.c | 94 ++++++++++++++++++++++++++--------------------
2 files changed, 55 insertions(+), 40 deletions(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index dc30b60..1d45716 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -222,6 +222,7 @@ struct ip6_flowlabel {
struct in6_addr dst;
struct ipv6_txoptions *opt;
unsigned long linger;
+ struct rcu_head rcu;
u8 share;
union {
struct pid *pid;
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 5d767f1..da15601 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -51,25 +51,33 @@
#define FL_HASH(l) (ntohl(l)&FL_HASH_MASK)
static atomic_t fl_size = ATOMIC_INIT(0);
-static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
+static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
static void ip6_fl_gc(unsigned long dummy);
static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
/* FL hash table lock: it protects only of GC */
-static DEFINE_RWLOCK(ip6_fl_lock);
+static DEFINE_SPINLOCK(ip6_fl_lock);
/* Big socket sock */
static DEFINE_RWLOCK(ip6_sk_fl_lock);
+#define for_each_fl_rcu(hash, fl) \
+ for (fl = rcu_dereference(fl_ht[(hash)]); \
+ fl != NULL; \
+ fl = rcu_dereference(fl->next))
+#define for_each_fl_continue_rcu(fl) \
+ for (fl = rcu_dereference(fl->next); \
+ fl != NULL; \
+ fl = rcu_dereference(fl->next))
static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
{
struct ip6_flowlabel *fl;
- for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) {
+ for_each_fl_rcu(FL_HASH(label), fl) {
if (fl->label == label && net_eq(fl->fl_net, net))
return fl;
}
@@ -80,11 +88,11 @@ static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
{
struct ip6_flowlabel *fl;
- read_lock_bh(&ip6_fl_lock);
+ rcu_read_lock_bh();
fl = __fl_lookup(net, label);
- if (fl)
- atomic_inc(&fl->users);
- read_unlock_bh(&ip6_fl_lock);
+ if (fl && !atomic_inc_not_zero(&fl->users))
+ fl = NULL;
+ rcu_read_unlock_bh();
return fl;
}
@@ -96,13 +104,13 @@ static void fl_free(struct ip6_flowlabel *fl)
put_pid(fl->owner.pid);
release_net(fl->fl_net);
kfree(fl->opt);
+ kfree_rcu(fl, rcu);
}
- kfree(fl);
}
static void fl_release(struct ip6_flowlabel *fl)
{
- write_lock_bh(&ip6_fl_lock);
+ spin_lock_bh(&ip6_fl_lock);
fl->lastuse = jiffies;
if (atomic_dec_and_test(&fl->users)) {
@@ -119,7 +127,7 @@ static void fl_release(struct ip6_flowlabel *fl)
time_after(ip6_fl_gc_timer.expires, ttd))
mod_timer(&ip6_fl_gc_timer, ttd);
}
- write_unlock_bh(&ip6_fl_lock);
+ spin_unlock_bh(&ip6_fl_lock);
}
static void ip6_fl_gc(unsigned long dummy)
@@ -128,12 +136,13 @@ static void ip6_fl_gc(unsigned long dummy)
unsigned long now = jiffies;
unsigned long sched = 0;
- write_lock(&ip6_fl_lock);
+ spin_lock(&ip6_fl_lock);
for (i=0; i<=FL_HASH_MASK; i++) {
struct ip6_flowlabel *fl, **flp;
flp = &fl_ht[i];
- while ((fl=*flp) != NULL) {
+ while ((fl = rcu_dereference_protected(*flp,
+ lockdep_is_held(&ip6_fl_lock))) != NULL) {
if (atomic_read(&fl->users) == 0) {
unsigned long ttd = fl->lastuse + fl->linger;
if (time_after(ttd, fl->expires))
@@ -156,18 +165,19 @@ static void ip6_fl_gc(unsigned long dummy)
if (sched) {
mod_timer(&ip6_fl_gc_timer, sched);
}
- write_unlock(&ip6_fl_lock);
+ spin_unlock(&ip6_fl_lock);
}
static void __net_exit ip6_fl_purge(struct net *net)
{
int i;
- write_lock(&ip6_fl_lock);
+ spin_lock(&ip6_fl_lock);
for (i = 0; i <= FL_HASH_MASK; i++) {
struct ip6_flowlabel *fl, **flp;
flp = &fl_ht[i];
- while ((fl = *flp) != NULL) {
+ while ((fl = rcu_dereference_protected(*flp,
+ lockdep_is_held(&ip6_fl_lock))) != NULL) {
if (net_eq(fl->fl_net, net) &&
atomic_read(&fl->users) == 0) {
*flp = fl->next;
@@ -178,7 +188,7 @@ static void __net_exit ip6_fl_purge(struct net *net)
flp = &fl->next;
}
}
- write_unlock(&ip6_fl_lock);
+ spin_unlock(&ip6_fl_lock);
}
static struct ip6_flowlabel *fl_intern(struct net *net,
@@ -188,7 +198,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
fl->label = label & IPV6_FLOWLABEL_MASK;
- write_lock_bh(&ip6_fl_lock);
+ spin_lock_bh(&ip6_fl_lock);
if (label == 0) {
for (;;) {
fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
@@ -210,16 +220,16 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
lfl = __fl_lookup(net, fl->label);
if (lfl != NULL) {
atomic_inc(&lfl->users);
- write_unlock_bh(&ip6_fl_lock);
+ spin_unlock_bh(&ip6_fl_lock);
return lfl;
}
}
fl->lastuse = jiffies;
fl->next = fl_ht[FL_HASH(fl->label)];
- fl_ht[FL_HASH(fl->label)] = fl;
+ rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
atomic_inc(&fl_size);
- write_unlock_bh(&ip6_fl_lock);
+ spin_unlock_bh(&ip6_fl_lock);
return NULL;
}
@@ -650,13 +660,13 @@ static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
struct net *net = seq_file_net(seq);
for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
- fl = fl_ht[state->bucket];
-
- while (fl && !net_eq(fl->fl_net, net))
- fl = fl->next;
- if (fl)
- break;
+ for_each_fl_rcu(state->bucket, fl) {
+ if (net_eq(fl->fl_net, net))
+ goto out;
+ }
}
+ fl = NULL;
+out:
return fl;
}
@@ -665,18 +675,22 @@ static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flo
struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
struct net *net = seq_file_net(seq);
- fl = fl->next;
+ for_each_fl_continue_rcu(fl) {
+ if (net_eq(fl->fl_net, net))
+ goto out;
+ }
+
try_again:
- while (fl && !net_eq(fl->fl_net, net))
- fl = fl->next;
-
- while (!fl) {
- if (++state->bucket <= FL_HASH_MASK) {
- fl = fl_ht[state->bucket];
- goto try_again;
- } else
- break;
+ if (++state->bucket <= FL_HASH_MASK) {
+ for_each_fl_rcu(state->bucket, fl) {
+ if (net_eq(fl->fl_net, net))
+ goto out;
+ }
+ goto try_again;
}
+ fl = NULL;
+
+out:
return fl;
}
@@ -690,9 +704,9 @@ static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
}
static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
- __acquires(ip6_fl_lock)
+ __acquires(RCU)
{
- read_lock_bh(&ip6_fl_lock);
+ rcu_read_lock_bh();
return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}
@@ -709,9 +723,9 @@ static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
}
static void ip6fl_seq_stop(struct seq_file *seq, void *v)
- __releases(ip6_fl_lock)
+ __releases(RCU)
{
- read_unlock_bh(&ip6_fl_lock);
+ rcu_read_unlock_bh();
}
static int ip6fl_seq_show(struct seq_file *seq, void *v)
--
1.7.9.5
--
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