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ipv6 flowlabel: Convert hash list to RCU.
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Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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YOSHIFUJI Hideaki / 吉藤英明 authored and David S. Miller committed Jan 31, 2013
1 parent f256dc5 commit d3aedd5
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Showing 2 changed files with 55 additions and 40 deletions.
1 change: 1 addition & 0 deletions include/net/ipv6.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
94 changes: 54 additions & 40 deletions net/ipv6/ip6_flowlabel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand All @@ -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;
}

Expand All @@ -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)) {
Expand All @@ -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)
Expand All @@ -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))
Expand All @@ -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;
Expand All @@ -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,
Expand All @@ -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;
Expand All @@ -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;
}

Expand Down Expand Up @@ -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;
}

Expand All @@ -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;
}

Expand All @@ -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;
}

Expand All @@ -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)
Expand Down

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