Commit 2e997d8b authored by David S. Miller's avatar David S. Miller

Merge branch 'ipv6-addrlabel-avoid-dirtying-ip6addrlbl_entry'

Eric Dumazet says:

====================
ipv6: addrlabel: avoid dirtying ip6addrlbl_entry

The refcount on ip6addrlbl_entry is only used to make sure ip6addrlbl_entry
does not disappear while ip6addrlbl_get() is allocating an skb.

We can instead allocate skb first, then use RCU, so that we no longer need
to refcount these structures.
====================
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 1ee87d7a 2809c095
......@@ -18,7 +18,6 @@
#include <linux/if_addrlabel.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/refcount.h>
#if 0
#define ADDRLABEL(x...) printk(x)
......@@ -36,7 +35,6 @@ struct ip6addrlbl_entry {
int addrtype;
u32 label;
struct hlist_node list;
refcount_t refcnt;
struct rcu_head rcu;
};
......@@ -111,28 +109,6 @@ static const __net_initconst struct ip6addrlbl_init_table
}
};
/* Object management */
static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
{
kfree(p);
}
static void ip6addrlbl_free_rcu(struct rcu_head *h)
{
ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
}
static bool ip6addrlbl_hold(struct ip6addrlbl_entry *p)
{
return refcount_inc_not_zero(&p->refcnt);
}
static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
{
if (refcount_dec_and_test(&p->refcnt))
call_rcu(&p->rcu, ip6addrlbl_free_rcu);
}
/* Find label */
static bool __ip6addrlbl_match(const struct ip6addrlbl_entry *p,
const struct in6_addr *addr,
......@@ -219,7 +195,6 @@ static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
newp->addrtype = addrtype;
newp->label = label;
INIT_HLIST_NODE(&newp->list);
refcount_set(&newp->refcnt, 1);
return newp;
}
......@@ -243,7 +218,7 @@ static int __ip6addrlbl_add(struct net *net, struct ip6addrlbl_entry *newp,
goto out;
}
hlist_replace_rcu(&p->list, &newp->list);
ip6addrlbl_put(p);
kfree_rcu(p, rcu);
goto out;
} else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
(p->prefixlen < newp->prefixlen)) {
......@@ -281,7 +256,7 @@ static int ip6addrlbl_add(struct net *net,
ret = __ip6addrlbl_add(net, newp, replace);
spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
if (ret)
ip6addrlbl_free(newp);
kfree(newp);
return ret;
}
......@@ -302,7 +277,7 @@ static int __ip6addrlbl_del(struct net *net,
p->ifindex == ifindex &&
ipv6_addr_equal(&p->prefix, prefix)) {
hlist_del_rcu(&p->list);
ip6addrlbl_put(p);
kfree_rcu(p, rcu);
ret = 0;
break;
}
......@@ -360,7 +335,7 @@ static void __net_exit ip6addrlbl_net_exit(struct net *net)
spin_lock(&net->ipv6.ip6addrlbl_table.lock);
hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
hlist_del_rcu(&p->list);
ip6addrlbl_put(p);
kfree_rcu(p, rcu);
}
spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
}
......@@ -546,38 +521,28 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
return -EINVAL;
addr = nla_data(tb[IFAL_ADDRESS]);
rcu_read_lock();
p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
if (p && !ip6addrlbl_hold(p))
p = NULL;
lseq = net->ipv6.ip6addrlbl_table.seq;
rcu_read_unlock();
if (!p) {
err = -ESRCH;
goto out;
}
skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL);
if (!skb) {
ip6addrlbl_put(p);
if (!skb)
return -ENOBUFS;
}
err = -ESRCH;
rcu_read_lock();
p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
lseq = net->ipv6.ip6addrlbl_table.seq;
if (p)
err = ip6addrlbl_fill(skb, p, lseq,
NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq,
RTM_NEWADDRLABEL, 0);
ip6addrlbl_put(p);
rcu_read_unlock();
if (err < 0) {
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto out;
}
} else {
err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
out:
}
return err;
}
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment