提交 4e985ada 编写于 作者: T Thomas Graf 提交者: David S. Miller

rtnl: provide link dump consistency info

This patch adds a change sequence counter to each net namespace
which is bumped whenever a netdevice is added or removed from
the list. If such a change occurred while a link dump took place,
the dump will have the NLM_F_DUMP_INTR flag set in the first
message which has been interrupted and in all subsequent messages
of the same dump.

Note that links may still be modified or renamed while a dump is
taking place but we can guarantee for userspace to receive a
complete list of links and not miss any.

Testing:
I have added 500 VLAN netdevices to make sure the dump is split
over multiple messages. Then while continuously dumping links in
one process I also continuously deleted and re-added a dummy
netdevice in another process. Multiple dumps per seconds have
had the NLM_F_DUMP_INTR flag set.

I guess we can wait for Johannes patch to hit net-next via the
wireless tree.  I just wanted to give this some testing right away.
Signed-off-by: NThomas Graf <tgraf@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 e77aeb71
...@@ -65,6 +65,7 @@ struct net { ...@@ -65,6 +65,7 @@ struct net {
struct list_head dev_base_head; struct list_head dev_base_head;
struct hlist_head *dev_name_head; struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head; struct hlist_head *dev_index_head;
unsigned int dev_base_seq; /* protected by rtnl_mutex */
/* core fib_rules */ /* core fib_rules */
struct list_head rules_ops; struct list_head rules_ops;
......
...@@ -199,6 +199,11 @@ static struct list_head ptype_all __read_mostly; /* Taps */ ...@@ -199,6 +199,11 @@ static struct list_head ptype_all __read_mostly; /* Taps */
DEFINE_RWLOCK(dev_base_lock); DEFINE_RWLOCK(dev_base_lock);
EXPORT_SYMBOL(dev_base_lock); EXPORT_SYMBOL(dev_base_lock);
static inline void dev_base_seq_inc(struct net *net)
{
while (++net->dev_base_seq == 0);
}
static inline struct hlist_head *dev_name_hash(struct net *net, const char *name) static inline struct hlist_head *dev_name_hash(struct net *net, const char *name)
{ {
unsigned hash = full_name_hash(name, strnlen(name, IFNAMSIZ)); unsigned hash = full_name_hash(name, strnlen(name, IFNAMSIZ));
...@@ -237,6 +242,9 @@ static int list_netdevice(struct net_device *dev) ...@@ -237,6 +242,9 @@ static int list_netdevice(struct net_device *dev)
hlist_add_head_rcu(&dev->index_hlist, hlist_add_head_rcu(&dev->index_hlist,
dev_index_hash(net, dev->ifindex)); dev_index_hash(net, dev->ifindex));
write_unlock_bh(&dev_base_lock); write_unlock_bh(&dev_base_lock);
dev_base_seq_inc(net);
return 0; return 0;
} }
...@@ -253,6 +261,8 @@ static void unlist_netdevice(struct net_device *dev) ...@@ -253,6 +261,8 @@ static void unlist_netdevice(struct net_device *dev)
hlist_del_rcu(&dev->name_hlist); hlist_del_rcu(&dev->name_hlist);
hlist_del_rcu(&dev->index_hlist); hlist_del_rcu(&dev->index_hlist);
write_unlock_bh(&dev_base_lock); write_unlock_bh(&dev_base_lock);
dev_base_seq_inc(dev_net(dev));
} }
/* /*
......
...@@ -129,6 +129,7 @@ static __net_init int setup_net(struct net *net) ...@@ -129,6 +129,7 @@ static __net_init int setup_net(struct net *net)
atomic_set(&net->count, 1); atomic_set(&net->count, 1);
atomic_set(&net->passive, 1); atomic_set(&net->passive, 1);
net->dev_base_seq = 1;
#ifdef NETNS_REFCNT_DEBUG #ifdef NETNS_REFCNT_DEBUG
atomic_set(&net->use_count, 0); atomic_set(&net->use_count, 0);
......
...@@ -1032,6 +1032,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) ...@@ -1032,6 +1032,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
s_idx = cb->args[1]; s_idx = cb->args[1];
rcu_read_lock(); rcu_read_lock();
cb->seq = net->dev_base_seq;
for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
idx = 0; idx = 0;
head = &net->dev_index_head[h]; head = &net->dev_index_head[h];
...@@ -1043,6 +1045,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) ...@@ -1043,6 +1045,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
cb->nlh->nlmsg_seq, 0, cb->nlh->nlmsg_seq, 0,
NLM_F_MULTI) <= 0) NLM_F_MULTI) <= 0)
goto out; goto out;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont: cont:
idx++; idx++;
} }
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册