@@ -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)
+/* Should be called 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
@@ -252,26 +232,37 @@ 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
+ id = __peernet2id(net, peer);
+ if (id >= 0) {
+ spin_unlock_bh(&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);
+ if (!maybe_get_net(peer)) {
+ spin_unlock_bh(&net->nsid_lock);
+ return NETNSA_NSID_NOT_ASSIGNED;
+ }
+
+ id = alloc_netid(net, peer, -1);
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);
+
+ 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);
__peernet2id_alloc() was used for both plain lookups and for netns ID allocations (depending the value of '*alloc'). Let's separate lookups from allocations instead. That is, integrate the lookup code into __peernet2id() and make peernet2id_alloc() responsible for allocating new netns IDs when necessary. This makes it clear that __peernet2id() doesn't modify the idr and prepares the code for lockless lookups. Also, mark the 'net' argument of __peernet2id() as 'const', since we're modifying this line. Signed-off-by: Guillaume Nault <gnault@redhat.com> --- net/core/net_namespace.c | 55 +++++++++++++++++----------------------- 1 file changed, 23 insertions(+), 32 deletions(-)