Commit 8d7e5dee authored by Guillaume Nault's avatar Guillaume Nault Committed by David S. Miller
Browse files

netns: don't disable BHs when locking "nsid_lock" 



When peernet2id() had to lock "nsid_lock" before iterating through the
nsid table, we had to disable BHs, because VXLAN can call peernet2id()
from the xmit path:
  vxlan_xmit() -> vxlan_fdb_miss() -> vxlan_fdb_notify()
    -> __vxlan_fdb_notify() -> vxlan_fdb_info() -> peernet2id().

Now that peernet2id() uses RCU protection, "nsid_lock" isn't used in BH
context anymore. Therefore, we can safely use plain
spin_lock()/spin_unlock() and let BHs run when holding "nsid_lock".

Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2dce224f

net/core/net_namespace.c

+11 −11
Original line number Diff line number Diff line
@@ -237,10 +237,10 @@ int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp) 
	if (refcount_read(&net->count) == 0)

		return NETNSA_NSID_NOT_ASSIGNED;



	spin_lock_bh(&net->nsid_lock);

	spin_lock(&net->nsid_lock);

	id = __peernet2id(net, peer);

	if (id >= 0) {

		spin_unlock_bh(&net->nsid_lock);

		spin_unlock(&net->nsid_lock);

		return id;

	}
@@ -250,12 +250,12 @@ int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp) 
	 * just been idr_remove()'d from there in cleanup_net().

	 */

	if (!maybe_get_net(peer)) {

		spin_unlock_bh(&net->nsid_lock);

		spin_unlock(&net->nsid_lock);

		return NETNSA_NSID_NOT_ASSIGNED;

	}



	id = alloc_netid(net, peer, -1);

	spin_unlock_bh(&net->nsid_lock);

	spin_unlock(&net->nsid_lock);



	put_net(peer);

	if (id < 0)
@@ -520,20 +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);
@@ -746,9 +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,
@@ -757,7 +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);

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