Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 90305829 authored by Jukka Rissanen's avatar Jukka Rissanen Committed by Marcel Holtmann
Browse files

Bluetooth: 6lowpan: Converting rwlocks to use RCU



The rwlocks are converted to use RCU. This helps performance as the
irq locks are not needed any more.

Signed-off-by: default avatarJukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent da213f8e
Loading
Loading
Loading
Loading
+127 −95
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ struct skb_cb {
 * The list contains struct lowpan_dev elements.
 */
static LIST_HEAD(bt_6lowpan_devices);
static DEFINE_RWLOCK(devices_lock);
static DEFINE_SPINLOCK(devices_lock);

/* If psm is set to 0 (default value), then 6lowpan is disabled.
 * Other values are used to indicate a Protocol Service Multiplexer
@@ -67,6 +67,7 @@ static struct l2cap_chan *listen_chan;

struct lowpan_peer {
	struct list_head list;
	struct rcu_head rcu;
	struct l2cap_chan *chan;

	/* peer addresses in various formats */
@@ -86,6 +87,13 @@ struct lowpan_dev {
	struct delayed_work notify_peers;
};

static inline void peer_free(struct rcu_head *head)
{
	struct lowpan_peer *e = container_of(head, struct lowpan_peer, rcu);

	kfree(e);
}

static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)
{
	return netdev_priv(netdev);
@@ -93,13 +101,14 @@ static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)

static inline void peer_add(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_add(&peer->list, &dev->peers);
	list_add_rcu(&peer->list, &dev->peers);
	atomic_inc(&dev->peer_count);
}

static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_del(&peer->list);
	list_del_rcu(&peer->list);
	call_rcu(&peer->rcu, peer_free);

	module_put(THIS_MODULE);

@@ -114,31 +123,37 @@ static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
						 bdaddr_t *ba, __u8 type)
{
	struct lowpan_peer *peer, *tmp;
	struct lowpan_peer *peer;

	BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
	       ba, type);

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
	rcu_read_lock();

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		BT_DBG("dst addr %pMR dst type %d",
		       &peer->chan->dst, peer->chan->dst_type);

		if (bacmp(&peer->chan->dst, ba))
			continue;

		if (type == peer->chan->dst_type)
		if (type == peer->chan->dst_type) {
			rcu_read_unlock();
			return peer;
		}
	}

	rcu_read_unlock();

	return NULL;
}

static inline struct lowpan_peer *peer_lookup_chan(struct lowpan_dev *dev,
static inline struct lowpan_peer *__peer_lookup_chan(struct lowpan_dev *dev,
						     struct l2cap_chan *chan)
{
	struct lowpan_peer *peer, *tmp;
	struct lowpan_peer *peer;

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
	list_for_each_entry_rcu(peer, &dev->peers, list) {
		if (peer->chan == chan)
			return peer;
	}
@@ -146,12 +161,12 @@ static inline struct lowpan_peer *peer_lookup_chan(struct lowpan_dev *dev,
	return NULL;
}

static inline struct lowpan_peer *peer_lookup_conn(struct lowpan_dev *dev,
static inline struct lowpan_peer *__peer_lookup_conn(struct lowpan_dev *dev,
						     struct l2cap_conn *conn)
{
	struct lowpan_peer *peer, *tmp;
	struct lowpan_peer *peer;

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
	list_for_each_entry_rcu(peer, &dev->peers, list) {
		if (peer->chan->conn == conn)
			return peer;
	}
@@ -163,7 +178,7 @@ static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,
						  struct in6_addr *daddr,
						  struct sk_buff *skb)
{
	struct lowpan_peer *peer, *tmp;
	struct lowpan_peer *peer;
	struct in6_addr *nexthop;
	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
	int count = atomic_read(&dev->peer_count);
@@ -174,9 +189,13 @@ static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,
	 * send the packet. If only one peer exists, then we can send the
	 * packet right away.
	 */
	if (count == 1)
		return list_first_entry(&dev->peers, struct lowpan_peer,
	if (count == 1) {
		rcu_read_lock();
		peer = list_first_or_null_rcu(&dev->peers, struct lowpan_peer,
					      list);
		rcu_read_unlock();
		return peer;
	}

	if (!rt) {
		nexthop = &lowpan_cb(skb)->gw;
@@ -195,53 +214,57 @@ static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,

	BT_DBG("gw %pI6c", nexthop);

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
	rcu_read_lock();

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		BT_DBG("dst addr %pMR dst type %d ip %pI6c",
		       &peer->chan->dst, peer->chan->dst_type,
		       &peer->peer_addr);

		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop))
		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
			rcu_read_unlock();
			return peer;
		}
	}

	rcu_read_unlock();

	return NULL;
}

static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_dev *entry;
	struct lowpan_peer *peer = NULL;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);
	rcu_read_lock();

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		peer = peer_lookup_conn(entry, conn);
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		peer = __peer_lookup_conn(entry, conn);
		if (peer)
			break;
	}

	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_unlock();

	return peer;
}

static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_dev *entry;
	struct lowpan_dev *dev = NULL;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);
	rcu_read_lock();

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		if (conn->hcon->hdev == entry->hdev) {
			dev = entry;
			break;
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_unlock();

	return dev;
}
@@ -264,13 +287,12 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
	u8 iphc0, iphc1;
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	unsigned long flags;

	dev = lowpan_dev(netdev);

	read_lock_irqsave(&devices_lock, flags);
	peer = peer_lookup_chan(dev, chan);
	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_lock();
	peer = __peer_lookup_chan(dev, chan);
	rcu_read_unlock();
	if (!peer)
		goto drop;

@@ -452,7 +474,6 @@ static int setup_header(struct sk_buff *skb, struct net_device *netdev,
	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
		lowpan_cb(skb)->chan = NULL;
	} else {
		unsigned long flags;
		u8 addr_type;

		/* Get destination BT device from skb.
@@ -463,19 +484,14 @@ static int setup_header(struct sk_buff *skb, struct net_device *netdev,
		BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
		       addr_type, &ipv6_daddr);

		read_lock_irqsave(&devices_lock, flags);
		peer = peer_lookup_ba(dev, &addr, addr_type);
		read_unlock_irqrestore(&devices_lock, flags);

		if (!peer) {
			/* The packet might be sent to 6lowpan interface
			 * because of routing (either via default route
			 * or user set route) so get peer according to
			 * the destination address.
			 */
			read_lock_irqsave(&devices_lock, flags);
			peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
			read_unlock_irqrestore(&devices_lock, flags);
			if (!peer) {
				BT_DBG("no such peer %pMR found", &addr);
				return -ENOENT;
@@ -558,14 +574,13 @@ static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
{
	struct sk_buff *local_skb;
	struct lowpan_dev *entry, *tmp;
	unsigned long flags;
	struct lowpan_dev *entry;
	int err = 0;

	read_lock_irqsave(&devices_lock, flags);
	rcu_read_lock();

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		struct lowpan_peer *pentry, *ptmp;
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		struct lowpan_peer *pentry;
		struct lowpan_dev *dev;

		if (entry->netdev != netdev)
@@ -573,7 +588,7 @@ static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)

		dev = lowpan_dev(entry->netdev);

		list_for_each_entry_safe(pentry, ptmp, &dev->peers, list) {
		list_for_each_entry_rcu(pentry, &dev->peers, list) {
			int ret;

			local_skb = skb_clone(skb, GFP_ATOMIC);
@@ -590,7 +605,7 @@ static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_unlock();

	return err;
}
@@ -792,7 +807,6 @@ static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
					struct lowpan_dev *dev)
{
	struct lowpan_peer *peer;
	unsigned long flags;

	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
	if (!peer)
@@ -815,10 +829,10 @@ static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
	 */
	set_ip_addr_bits(chan->dst_type, (u8 *)&peer->peer_addr.s6_addr + 8);

	write_lock_irqsave(&devices_lock, flags);
	spin_lock(&devices_lock);
	INIT_LIST_HEAD(&peer->list);
	peer_add(dev, peer);
	write_unlock_irqrestore(&devices_lock, flags);
	spin_unlock(&devices_lock);

	/* Notifying peers about us needs to be done without locks held */
	INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
@@ -831,7 +845,6 @@ static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
{
	struct net_device *netdev;
	int err = 0;
	unsigned long flags;

	netdev = alloc_netdev(sizeof(struct lowpan_dev), IFACE_NAME_TEMPLATE,
			      NET_NAME_UNKNOWN, netdev_setup);
@@ -861,10 +874,10 @@ static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
	(*dev)->hdev = chan->conn->hcon->hdev;
	INIT_LIST_HEAD(&(*dev)->peers);

	write_lock_irqsave(&devices_lock, flags);
	spin_lock(&devices_lock);
	INIT_LIST_HEAD(&(*dev)->list);
	list_add(&(*dev)->list, &bt_6lowpan_devices);
	write_unlock_irqrestore(&devices_lock, flags);
	list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
	spin_unlock(&devices_lock);

	return 0;

@@ -918,11 +931,10 @@ static void delete_netdev(struct work_struct *work)

static void chan_close_cb(struct l2cap_chan *chan)
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_dev *entry;
	struct lowpan_dev *dev = NULL;
	struct lowpan_peer *peer;
	int err = -ENOENT;
	unsigned long flags;
	bool last = false, removed = true;

	BT_DBG("chan %p conn %p", chan, chan->conn);
@@ -937,11 +949,11 @@ static void chan_close_cb(struct l2cap_chan *chan)
		removed = false;
	}

	write_lock_irqsave(&devices_lock, flags);
	spin_lock(&devices_lock);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		dev = lowpan_dev(entry->netdev);
		peer = peer_lookup_chan(dev, chan);
		peer = __peer_lookup_chan(dev, chan);
		if (peer) {
			last = peer_del(dev, peer);
			err = 0;
@@ -952,13 +964,12 @@ static void chan_close_cb(struct l2cap_chan *chan)
			       atomic_read(&chan->kref.refcount));

			l2cap_chan_put(chan);
			kfree(peer);
			break;
		}
	}

	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
		write_unlock_irqrestore(&devices_lock, flags);
		spin_unlock(&devices_lock);

		cancel_delayed_work_sync(&dev->notify_peers);

@@ -969,7 +980,7 @@ static void chan_close_cb(struct l2cap_chan *chan)
			schedule_work(&entry->delete_netdev);
		}
	} else {
		write_unlock_irqrestore(&devices_lock, flags);
		spin_unlock(&devices_lock);
	}

	return;
@@ -1161,10 +1172,9 @@ static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,

static void disconnect_all_peers(void)
{
	struct lowpan_dev *entry, *tmp_dev;
	struct lowpan_dev *entry;
	struct lowpan_peer *peer, *tmp_peer, *new_peer;
	struct list_head peers;
	unsigned long flags;

	INIT_LIST_HEAD(&peers);

@@ -1173,10 +1183,10 @@ static void disconnect_all_peers(void)
	 * with the same list at the same time.
	 */

	read_lock_irqsave(&devices_lock, flags);
	rcu_read_lock();

	list_for_each_entry_safe(entry, tmp_dev, &bt_6lowpan_devices, list) {
		list_for_each_entry_safe(peer, tmp_peer, &entry->peers, list) {
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		list_for_each_entry_rcu(peer, &entry->peers, list) {
			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
			if (!new_peer)
				break;
@@ -1188,26 +1198,36 @@ static void disconnect_all_peers(void)
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_unlock();

	spin_lock(&devices_lock);
	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
		l2cap_chan_close(peer->chan, ENOENT);
		kfree(peer);

		list_del_rcu(&peer->list);
		call_rcu(&peer->rcu, peer_free);

		module_put(THIS_MODULE);
	}
	spin_unlock(&devices_lock);
}

static int lowpan_psm_set(void *data, u64 val)
{
struct set_psm {
	struct work_struct work;
	u16 psm;
};

	psm = val;
	if (psm == 0 || psm_6lowpan != psm)
static void do_psm_set(struct work_struct *work)
{
	struct set_psm *set_psm = container_of(work, struct set_psm, work);

	if (set_psm->psm == 0 || psm_6lowpan != set_psm->psm)
		/* Disconnect existing connections if 6lowpan is
		 * disabled (psm = 0), or if psm changes.
		 */
		disconnect_all_peers();

	psm_6lowpan = psm;
	psm_6lowpan = set_psm->psm;

	if (listen_chan) {
		l2cap_chan_close(listen_chan, 0);
@@ -1216,6 +1236,22 @@ static int lowpan_psm_set(void *data, u64 val)

	listen_chan = bt_6lowpan_listen();

	kfree(set_psm);
}

static int lowpan_psm_set(void *data, u64 val)
{
	struct set_psm *set_psm;

	set_psm = kzalloc(sizeof(*set_psm), GFP_KERNEL);
	if (!set_psm)
		return -ENOMEM;

	set_psm->psm = val;
	INIT_WORK(&set_psm->work, do_psm_set);

	schedule_work(&set_psm->work);

	return 0;
}

@@ -1297,19 +1333,18 @@ static ssize_t lowpan_control_write(struct file *fp,

static int lowpan_control_show(struct seq_file *f, void *ptr)
{
	struct lowpan_dev *entry, *tmp_dev;
	struct lowpan_peer *peer, *tmp_peer;
	unsigned long flags;
	struct lowpan_dev *entry;
	struct lowpan_peer *peer;

	read_lock_irqsave(&devices_lock, flags);
	spin_lock(&devices_lock);

	list_for_each_entry_safe(entry, tmp_dev, &bt_6lowpan_devices, list) {
		list_for_each_entry_safe(peer, tmp_peer, &entry->peers, list)
	list_for_each_entry(entry, &bt_6lowpan_devices, list) {
		list_for_each_entry(peer, &entry->peers, list)
			seq_printf(f, "%pMR (type %u)\n",
				   &peer->chan->dst, peer->chan->dst_type);
	}

	read_unlock_irqrestore(&devices_lock, flags);
	spin_unlock(&devices_lock);

	return 0;
}
@@ -1329,9 +1364,8 @@ static const struct file_operations lowpan_control_fops = {

static void disconnect_devices(void)
{
	struct lowpan_dev *entry, *tmp, *new_dev;
	struct lowpan_dev *entry, *new_dev;
	struct list_head devices;
	unsigned long flags;

	INIT_LIST_HEAD(&devices);

@@ -1340,9 +1374,9 @@ static void disconnect_devices(void)
	 * devices list.
	 */

	read_lock_irqsave(&devices_lock, flags);
	rcu_read_lock();

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
		if (!new_dev)
			break;
@@ -1350,12 +1384,12 @@ static void disconnect_devices(void)
		new_dev->netdev = entry->netdev;
		INIT_LIST_HEAD(&new_dev->list);

		list_add(&new_dev->list, &devices);
		list_add_rcu(&new_dev->list, &devices);
	}

	read_unlock_irqrestore(&devices_lock, flags);
	rcu_read_unlock();

	list_for_each_entry_safe(entry, tmp, &devices, list) {
	list_for_each_entry(entry, &devices, list) {
		ifdown(entry->netdev);
		BT_DBG("Unregistering netdev %s %p",
		       entry->netdev->name, entry->netdev);
@@ -1368,17 +1402,15 @@ static int device_event(struct notifier_block *unused,
			unsigned long event, void *ptr)
{
	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
	struct lowpan_dev *entry, *tmp;
	unsigned long flags;
	struct lowpan_dev *entry;

	if (netdev->type != ARPHRD_6LOWPAN)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UNREGISTER:
		write_lock_irqsave(&devices_lock, flags);
		list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices,
					 list) {
		spin_lock(&devices_lock);
		list_for_each_entry(entry, &bt_6lowpan_devices, list) {
			if (entry->netdev == netdev) {
				BT_DBG("Unregistered netdev %s %p",
				       netdev->name, netdev);
@@ -1387,7 +1419,7 @@ static int device_event(struct notifier_block *unused,
				break;
			}
		}
		write_unlock_irqrestore(&devices_lock, flags);
		spin_unlock(&devices_lock);
		break;
	}