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

net/bluetooth/6lowpan.c

+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;

	}