Commit 5b7cfe06 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'mptcp-pm-lockless-list-traversal-and-cleanup' 

Matthieu Baerts says:

====================
mptcp: pm: lockless list traversal and cleanup

Here are two patches improving the MPTCP in-kernel path-manager.

- Patch 1: the get and dump endpoints operations are iterating over the
  endpoints list in a lockless way.

- Patch 2: reduce the code duplication to lookup an endpoint.
====================

Link: https://patch.msgid.link/20241115-net-next-mptcp-pm-lockless-dump-v1-0-f4a1bcb4ca2c@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents cc84d89a 1d7fa6ce

net/mptcp/pm_netlink.c

+13 −20
Original line number Diff line number Diff line
@@ -512,7 +512,8 @@ __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id) 
{

	struct mptcp_pm_addr_entry *entry;



	list_for_each_entry(entry, &pernet->local_addr_list, list) {

	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,

				lockdep_is_held(&pernet->lock)) {

		if (entry->addr.id == id)

			return entry;

	}
@@ -1142,17 +1143,13 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc 
{

	struct mptcp_pm_addr_entry *entry;

	struct pm_nl_pernet *pernet;

	int ret = -1;

	int ret;



	pernet = pm_nl_get_pernet_from_msk(msk);



	rcu_read_lock();

	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {

		if (mptcp_addresses_equal(&entry->addr, skc, entry->addr.port)) {

			ret = entry->addr.id;

			break;

		}

	}

	entry = __lookup_addr(pernet, skc);

	ret = entry ? entry->addr.id : -1;

	rcu_read_unlock();

	if (ret >= 0)

		return ret;
@@ -1179,15 +1176,11 @@ bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc) 
{

	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);

	struct mptcp_pm_addr_entry *entry;

	bool backup = false;

	bool backup;



	rcu_read_lock();

	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {

		if (mptcp_addresses_equal(&entry->addr, skc, entry->addr.port)) {

			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);

			break;

		}

	}

	entry = __lookup_addr(pernet, skc);

	backup = entry && !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);

	rcu_read_unlock();



	return backup;
@@ -1824,7 +1817,7 @@ int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info) 
		goto fail;

	}



	spin_lock_bh(&pernet->lock);

	rcu_read_lock();

	entry = __lookup_addr_by_id(pernet, addr.addr.id);

	if (!entry) {

		GENL_SET_ERR_MSG(info, "address not found");
@@ -1838,11 +1831,11 @@ int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info) 


	genlmsg_end(msg, reply);

	ret = genlmsg_reply(msg, info);

	spin_unlock_bh(&pernet->lock);

	rcu_read_unlock();

	return ret;



unlock_fail:

	spin_unlock_bh(&pernet->lock);

	rcu_read_unlock();



fail:

	nlmsg_free(msg);
@@ -1866,7 +1859,7 @@ int mptcp_pm_nl_dump_addr(struct sk_buff *msg, 


	pernet = pm_nl_get_pernet(net);



	spin_lock_bh(&pernet->lock);

	rcu_read_lock();

	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {

		if (test_bit(i, pernet->id_bitmap)) {

			entry = __lookup_addr_by_id(pernet, i);
@@ -1891,7 +1884,7 @@ int mptcp_pm_nl_dump_addr(struct sk_buff *msg, 
			genlmsg_end(msg, hdr);

		}

	}

	spin_unlock_bh(&pernet->lock);

	rcu_read_unlock();



	cb->args[0] = id;

	return msg->len;