* [PATCH net-next 1/2] ipv6: addrlabel: rework ip6addrlbl_get()
2017-10-09 16:52 [PATCH net-next 0/2] ipv6: addrlabel: avoid dirtying ip6addrlbl_entry Eric Dumazet
@ 2017-10-09 16:52 ` Eric Dumazet
2017-10-09 16:52 ` [PATCH net-next 2/2] ipv6: addrlabel: remove refcounting Eric Dumazet
2017-10-09 17:44 ` [PATCH net-next 0/2] ipv6: addrlabel: avoid dirtying ip6addrlbl_entry Martin KaFai Lau
2 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2017-10-09 16:52 UTC (permalink / raw)
To: David S . Miller; +Cc: netdev, Eric Dumazet, Eric Dumazet, Hideaki YOSHIFUJI
If we allocate skb before the lookup, we can use RCU
without the need of ip6addrlbl_hold()
This means that the following patch can get rid of refcounting.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv6/addrlabel.c | 36 +++++++++++++-----------------------
1 file changed, 13 insertions(+), 23 deletions(-)
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index c6311d7108f651c7385cd6316752ba4a86667dcc..f31489652c4ae1fc0c93d1756e13717f0689b0ab 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -546,38 +546,28 @@ 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 = ip6addrlbl_fill(skb, p, lseq,
- NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
- RTM_NEWADDRLABEL, 0);
+ err = -ESRCH;
- ip6addrlbl_put(p);
+ 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,
+ RTM_NEWADDRLABEL, 0);
+ 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);
}
-
- err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
-out:
return err;
}
--
2.14.2.920.gcf0c67979c-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH net-next 2/2] ipv6: addrlabel: remove refcounting
2017-10-09 16:52 [PATCH net-next 0/2] ipv6: addrlabel: avoid dirtying ip6addrlbl_entry Eric Dumazet
2017-10-09 16:52 ` [PATCH net-next 1/2] ipv6: addrlabel: rework ip6addrlbl_get() Eric Dumazet
@ 2017-10-09 16:52 ` Eric Dumazet
2017-10-09 17:44 ` [PATCH net-next 0/2] ipv6: addrlabel: avoid dirtying ip6addrlbl_entry Martin KaFai Lau
2 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2017-10-09 16:52 UTC (permalink / raw)
To: David S . Miller; +Cc: netdev, Eric Dumazet, Eric Dumazet, Hideaki YOSHIFUJI
After previous patch ("ipv6: addrlabel: rework ip6addrlbl_get()")
we can remove the refcount from struct ip6addrlbl_entry,
since it is no longer elevated in p6addrlbl_get()
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv6/addrlabel.c | 33 ++++-----------------------------
1 file changed, 4 insertions(+), 29 deletions(-)
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index f31489652c4ae1fc0c93d1756e13717f0689b0ab..2606d2fa3ac4c8e7d13071d1895cf4e6e36a4116 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -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);
}
--
2.14.2.920.gcf0c67979c-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread