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IPv6: convert addrconf hash list to RCU
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Convert from reader/writer lock to RCU and spinlock for addrconf
hash list.

Adds an additional helper macro for hlist_for_each_entry_continue_rcu
to handle the continue case.

Signed-off-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@davem330
stephen hemminger authored and davem330 committed Mar 20, 2010
1 parent c2e2129 commit 5c578ae
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Showing 3 changed files with 58 additions and 41 deletions.
13 changes: 13 additions & 0 deletions include/linux/rculist.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -428,5 +428,18 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
pos = rcu_dereference_raw(pos->next))

/**
* hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_continue_rcu(tpos, pos, member) \
for (pos = rcu_dereference((pos)->next); \
pos && ({ prefetch(pos->next); 1; }) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
pos = rcu_dereference(pos->next))


#endif /* __KERNEL__ */
#endif
1 change: 1 addition & 0 deletions include/net/if_inet6.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,7 @@ struct inet6_ifaddr {
#endif

int dead;
struct rcu_head rcu;
};

struct ip6_sf_socklist {
Expand Down
85 changes: 44 additions & 41 deletions net/ipv6/addrconf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -127,7 +127,7 @@ static int ipv6_count_addresses(struct inet6_dev *idev);
* Configured unicast address hash table
*/
static struct hlist_head inet6_addr_lst[IN6_ADDR_HSIZE];
static DEFINE_RWLOCK(addrconf_hash_lock);
static DEFINE_SPINLOCK(addrconf_hash_lock);

static void addrconf_verify(unsigned long);

Expand Down Expand Up @@ -523,8 +523,13 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old)
}
#endif

/* Nobody refers to this ifaddr, destroy it */
static void inet6_ifa_finish_destroy_rcu(struct rcu_head *head)
{
struct inet6_ifaddr *ifp = container_of(head, struct inet6_ifaddr, rcu);
kfree(ifp);
}

/* Nobody refers to this ifaddr, destroy it */
void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
{
WARN_ON(ifp->if_next != NULL);
Expand All @@ -545,7 +550,7 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
}
dst_release(&ifp->rt->u.dst);

kfree(ifp);
call_rcu(&ifp->rcu, inet6_ifa_finish_destroy_rcu);
}

static void
Expand Down Expand Up @@ -616,7 +621,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
goto out2;
}

write_lock(&addrconf_hash_lock);
spin_lock(&addrconf_hash_lock);

/* Ignore adding duplicate addresses on an interface */
if (ipv6_chk_same_addr(dev_net(idev->dev), addr, idev->dev)) {
Expand Down Expand Up @@ -670,9 +675,9 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
/* Add to big hash table */
hash = ipv6_addr_hash(addr);

hlist_add_head(&ifa->addr_lst, &inet6_addr_lst[hash]);
hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
in6_ifa_hold(ifa);
write_unlock(&addrconf_hash_lock);
spin_unlock(&addrconf_hash_lock);

write_lock(&idev->lock);
/* Add to inet6_dev unicast addr list. */
Expand All @@ -699,7 +704,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,

return ifa;
out:
write_unlock(&addrconf_hash_lock);
spin_unlock(&addrconf_hash_lock);
goto out2;
}

Expand All @@ -717,10 +722,10 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)

ifp->dead = 1;

write_lock_bh(&addrconf_hash_lock);
hlist_del_init(&ifp->addr_lst);
spin_lock_bh(&addrconf_hash_lock);
hlist_del_init_rcu(&ifp->addr_lst);
__in6_ifa_put(ifp);
write_unlock_bh(&addrconf_hash_lock);
spin_unlock_bh(&addrconf_hash_lock);

write_lock_bh(&idev->lock);
#ifdef CONFIG_IPV6_PRIVACY
Expand Down Expand Up @@ -1274,8 +1279,8 @@ int ipv6_chk_addr(struct net *net, struct in6_addr *addr,
struct hlist_node *node;
u8 hash = ipv6_addr_hash(addr);

read_lock_bh(&addrconf_hash_lock);
hlist_for_each_entry(ifp, node, &inet6_addr_lst[hash], addr_lst) {
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, node, &inet6_addr_lst[hash], addr_lst) {
if (!net_eq(dev_net(ifp->idev->dev), net))
continue;
if (ipv6_addr_equal(&ifp->addr, addr) &&
Expand All @@ -1285,7 +1290,8 @@ int ipv6_chk_addr(struct net *net, struct in6_addr *addr,
break;
}
}
read_unlock_bh(&addrconf_hash_lock);
rcu_read_unlock_bh();

return ifp != NULL;
}
EXPORT_SYMBOL(ipv6_chk_addr);
Expand Down Expand Up @@ -1341,8 +1347,8 @@ struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *add
struct hlist_node *node;
u8 hash = ipv6_addr_hash(addr);

read_lock_bh(&addrconf_hash_lock);
hlist_for_each_entry(ifp, node, &inet6_addr_lst[hash], addr_lst) {
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, node, &inet6_addr_lst[hash], addr_lst) {
if (!net_eq(dev_net(ifp->idev->dev), net))
continue;
if (ipv6_addr_equal(&ifp->addr, addr)) {
Expand All @@ -1353,7 +1359,7 @@ struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *add
}
}
}
read_unlock_bh(&addrconf_hash_lock);
rcu_read_unlock_bh();

return ifp;
}
Expand Down Expand Up @@ -2698,10 +2704,10 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_unlock_bh(&idev->lock);

/* clear hash table */
write_lock_bh(&addrconf_hash_lock);
hlist_del_init(&ifa->addr_lst);
spin_lock_bh(&addrconf_hash_lock);
hlist_del_init_rcu(&ifa->addr_lst);
__in6_ifa_put(ifa);
write_unlock_bh(&addrconf_hash_lock);
spin_unlock_bh(&addrconf_hash_lock);

__ipv6_ifa_notify(RTM_DELADDR, ifa);
atomic_notifier_call_chain(&inet6addr_chain, NETDEV_DOWN, ifa);
Expand Down Expand Up @@ -2946,11 +2952,10 @@ static struct inet6_ifaddr *if6_get_first(struct seq_file *seq)

for (state->bucket = 0; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {
struct hlist_node *n;
hlist_for_each_entry(ifa, n,
&inet6_addr_lst[state->bucket], addr_lst) {
hlist_for_each_entry_rcu(ifa, n, &inet6_addr_lst[state->bucket],
addr_lst)
if (net_eq(dev_net(ifa->idev->dev), net))
return ifa;
}
}
return NULL;
}
Expand All @@ -2962,10 +2967,9 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
struct net *net = seq_file_net(seq);
struct hlist_node *n = &ifa->addr_lst;

hlist_for_each_entry_continue(ifa, n, addr_lst) {
hlist_for_each_entry_continue_rcu(ifa, n, addr_lst)
if (net_eq(dev_net(ifa->idev->dev), net))
return ifa;
}

while (++state->bucket < IN6_ADDR_HSIZE) {
hlist_for_each_entry(ifa, n,
Expand All @@ -2989,9 +2993,9 @@ static struct inet6_ifaddr *if6_get_idx(struct seq_file *seq, loff_t pos)
}

static void *if6_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(addrconf_hash_lock)
__acquires(rcu)
{
read_lock_bh(&addrconf_hash_lock);
rcu_read_lock_bh();
return if6_get_idx(seq, *pos);
}

Expand All @@ -3005,9 +3009,9 @@ static void *if6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
}

static void if6_seq_stop(struct seq_file *seq, void *v)
__releases(addrconf_hash_lock)
__releases(rcu)
{
read_unlock_bh(&addrconf_hash_lock);
rcu_read_unlock_bh();
}

static int if6_seq_show(struct seq_file *seq, void *v)
Expand Down Expand Up @@ -3081,8 +3085,8 @@ int ipv6_chk_home_addr(struct net *net, struct in6_addr *addr)
struct hlist_node *n;
u8 hash = ipv6_addr_hash(addr);

read_lock_bh(&addrconf_hash_lock);
hlist_for_each_entry(ifp, n, &inet6_addr_lst[hash], addr_lst) {
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, n, &inet6_addr_lst[hash], addr_lst) {
if (!net_eq(dev_net(ifp->idev->dev), net))
continue;
if (ipv6_addr_equal(&ifp->addr, addr) &&
Expand All @@ -3091,7 +3095,7 @@ int ipv6_chk_home_addr(struct net *net, struct in6_addr *addr)
break;
}
}
read_unlock_bh(&addrconf_hash_lock);
rcu_read_unlock_bh();
return ret;
}
#endif
Expand All @@ -3107,7 +3111,8 @@ static void addrconf_verify(unsigned long foo)
unsigned long now, next;
int i;

spin_lock_bh(&addrconf_verify_lock);
rcu_read_lock_bh();
spin_lock(&addrconf_verify_lock);
now = jiffies;
next = now + ADDR_CHECK_FREQUENCY;

Expand All @@ -3116,8 +3121,8 @@ static void addrconf_verify(unsigned long foo)
for (i=0; i < IN6_ADDR_HSIZE; i++) {

restart:
read_lock(&addrconf_hash_lock);
hlist_for_each_entry(ifp, node, &inet6_addr_lst[i], addr_lst) {
hlist_for_each_entry_rcu(ifp, node,
&inet6_addr_lst[i], addr_lst) {
unsigned long age;
#ifdef CONFIG_IPV6_PRIVACY
unsigned long regen_advance;
Expand All @@ -3139,7 +3144,6 @@ static void addrconf_verify(unsigned long foo)
age >= ifp->valid_lft) {
spin_unlock(&ifp->lock);
in6_ifa_hold(ifp);
read_unlock(&addrconf_hash_lock);
ipv6_del_addr(ifp);
goto restart;
} else if (ifp->prefered_lft == INFINITY_LIFE_TIME) {
Expand All @@ -3161,7 +3165,6 @@ static void addrconf_verify(unsigned long foo)

if (deprecate) {
in6_ifa_hold(ifp);
read_unlock(&addrconf_hash_lock);

ipv6_ifa_notify(0, ifp);
in6_ifa_put(ifp);
Expand All @@ -3179,7 +3182,7 @@ static void addrconf_verify(unsigned long foo)
in6_ifa_hold(ifp);
in6_ifa_hold(ifpub);
spin_unlock(&ifp->lock);
read_unlock(&addrconf_hash_lock);

spin_lock(&ifpub->lock);
ifpub->regen_count = 0;
spin_unlock(&ifpub->lock);
Expand All @@ -3199,12 +3202,12 @@ static void addrconf_verify(unsigned long foo)
spin_unlock(&ifp->lock);
}
}
read_unlock(&addrconf_hash_lock);
}

addr_chk_timer.expires = time_before(next, jiffies + HZ) ? jiffies + HZ : next;
add_timer(&addr_chk_timer);
spin_unlock_bh(&addrconf_verify_lock);
spin_unlock(&addrconf_verify_lock);
rcu_read_unlock_bh();
}

static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local)
Expand Down Expand Up @@ -4621,10 +4624,10 @@ void addrconf_cleanup(void)
/*
* Check hash table.
*/
write_lock_bh(&addrconf_hash_lock);
spin_lock_bh(&addrconf_hash_lock);
for (i = 0; i < IN6_ADDR_HSIZE; i++)
WARN_ON(!hlist_empty(&inet6_addr_lst[i]));
write_unlock_bh(&addrconf_hash_lock);
spin_unlock_bh(&addrconf_hash_lock);

del_timer(&addr_chk_timer);
rtnl_unlock();
Expand Down

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