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Diffstat (limited to 'net/core/net_namespace.c')
-rw-r--r--net/core/net_namespace.c99
1 files changed, 41 insertions, 58 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 39402840025e..757cc1d084e7 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -211,16 +211,10 @@ static int net_eq_idr(int id, void *net, void *peer)
return 0;
}
-/* Should be called with nsid_lock held. If a new id is assigned, the bool alloc
- * is set to true, thus the caller knows that the new id must be notified via
- * rtnl.
- */
-static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
+/* Must be called from RCU-critical section or with nsid_lock held */
+static int __peernet2id(const struct net *net, struct net *peer)
{
int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
- bool alloc_it = *alloc;
-
- *alloc = false;
/* Magic value for id 0. */
if (id == NET_ID_ZERO)
@@ -228,23 +222,9 @@ static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
if (id > 0)
return id;
- if (alloc_it) {
- id = alloc_netid(net, peer, -1);
- *alloc = true;
- return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
- }
-
return NETNSA_NSID_NOT_ASSIGNED;
}
-/* should be called with nsid_lock held */
-static int __peernet2id(struct net *net, struct net *peer)
-{
- bool no = false;
-
- return __peernet2id_alloc(net, peer, &no);
-}
-
static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
struct nlmsghdr *nlh, gfp_t gfp);
/* This function returns the id of a peer netns. If no id is assigned, one will
@@ -252,38 +232,50 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
*/
int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp)
{
- bool alloc = false, alive = false;
int id;
if (refcount_read(&net->count) == 0)
return NETNSA_NSID_NOT_ASSIGNED;
- spin_lock_bh(&net->nsid_lock);
- /*
- * When peer is obtained from RCU lists, we may race with
+
+ spin_lock(&net->nsid_lock);
+ id = __peernet2id(net, peer);
+ if (id >= 0) {
+ spin_unlock(&net->nsid_lock);
+ return id;
+ }
+
+ /* When peer is obtained from RCU lists, we may race with
* its cleanup. Check whether it's alive, and this guarantees
* we never hash a peer back to net->netns_ids, after it has
* just been idr_remove()'d from there in cleanup_net().
*/
- if (maybe_get_net(peer))
- alive = alloc = true;
- id = __peernet2id_alloc(net, peer, &alloc);
- spin_unlock_bh(&net->nsid_lock);
- if (alloc && id >= 0)
- rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp);
- if (alive)
- put_net(peer);
+ if (!maybe_get_net(peer)) {
+ spin_unlock(&net->nsid_lock);
+ return NETNSA_NSID_NOT_ASSIGNED;
+ }
+
+ id = alloc_netid(net, peer, -1);
+ spin_unlock(&net->nsid_lock);
+
+ put_net(peer);
+ if (id < 0)
+ return NETNSA_NSID_NOT_ASSIGNED;
+
+ rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp);
+
return id;
}
EXPORT_SYMBOL_GPL(peernet2id_alloc);
/* This function returns, if assigned, the id of a peer netns. */
-int peernet2id(struct net *net, struct net *peer)
+int peernet2id(const struct net *net, struct net *peer)
{
int id;
- spin_lock_bh(&net->nsid_lock);
+ rcu_read_lock();
id = __peernet2id(net, peer);
- spin_unlock_bh(&net->nsid_lock);
+ rcu_read_unlock();
+
return id;
}
EXPORT_SYMBOL(peernet2id);
@@ -291,12 +283,12 @@ EXPORT_SYMBOL(peernet2id);
/* This function returns true is the peer netns has an id assigned into the
* current netns.
*/
-bool peernet_has_id(struct net *net, struct net *peer)
+bool peernet_has_id(const struct net *net, struct net *peer)
{
return peernet2id(net, peer) >= 0;
}
-struct net *get_net_ns_by_id(struct net *net, int id)
+struct net *get_net_ns_by_id(const struct net *net, int id)
{
struct net *peer;
@@ -528,20 +520,20 @@ static void unhash_nsid(struct net *net, struct net *last)
for_each_net(tmp) {
int id;
- spin_lock_bh(&tmp->nsid_lock);
+ spin_lock(&tmp->nsid_lock);
id = __peernet2id(tmp, net);
if (id >= 0)
idr_remove(&tmp->netns_ids, id);
- spin_unlock_bh(&tmp->nsid_lock);
+ spin_unlock(&tmp->nsid_lock);
if (id >= 0)
rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL,
GFP_KERNEL);
if (tmp == last)
break;
}
- spin_lock_bh(&net->nsid_lock);
+ spin_lock(&net->nsid_lock);
idr_destroy(&net->netns_ids);
- spin_unlock_bh(&net->nsid_lock);
+ spin_unlock(&net->nsid_lock);
}
static LLIST_HEAD(cleanup_list);
@@ -754,9 +746,9 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
return PTR_ERR(peer);
}
- spin_lock_bh(&net->nsid_lock);
+ spin_lock(&net->nsid_lock);
if (__peernet2id(net, peer) >= 0) {
- spin_unlock_bh(&net->nsid_lock);
+ spin_unlock(&net->nsid_lock);
err = -EEXIST;
NL_SET_BAD_ATTR(extack, nla);
NL_SET_ERR_MSG(extack,
@@ -765,7 +757,7 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
}
err = alloc_netid(net, peer, nsid);
- spin_unlock_bh(&net->nsid_lock);
+ spin_unlock(&net->nsid_lock);
if (err >= 0) {
rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid,
nlh, GFP_KERNEL);
@@ -950,6 +942,7 @@ struct rtnl_net_dump_cb {
int s_idx;
};
+/* Runs in RCU-critical section. */
static int rtnl_net_dumpid_one(int id, void *peer, void *data)
{
struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
@@ -1034,19 +1027,9 @@ static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
goto end;
}
- spin_lock_bh(&net_cb.tgt_net->nsid_lock);
- if (net_cb.fillargs.add_ref &&
- !net_eq(net_cb.ref_net, net_cb.tgt_net) &&
- !spin_trylock_bh(&net_cb.ref_net->nsid_lock)) {
- spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
- err = -EAGAIN;
- goto end;
- }
+ rcu_read_lock();
idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
- if (net_cb.fillargs.add_ref &&
- !net_eq(net_cb.ref_net, net_cb.tgt_net))
- spin_unlock_bh(&net_cb.ref_net->nsid_lock);
- spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
+ rcu_read_unlock();
cb->args[0] = net_cb.idx;
end:
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-28 07:00:06 +0300