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Commit 9c903e37 authored by David Herrmann's avatar David Herrmann Committed by Gustavo Padovan
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Bluetooth: l2cap: introduce l2cap_conn ref-counting 



If we want to use l2cap_conn outside of l2cap_core.c, we need refcounting
for these objects. Otherwise, we cannot synchronize l2cap locks with
outside locks and end up with deadlocks.

Hence, introduce ref-counting for l2cap_conn objects. This doesn't affect
l2cap internals at all, as they use a direct synchronization.
We also keep a reference to the parent hci_conn for locking purposes as
l2cap_conn depends on this. This doesn't affect the connection itself but
only the lifetime of the (dead) object.

Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.co.uk>
parent 3764eaa9

include/net/bluetooth/l2cap.h

+4 −0
Original line number Diff line number Diff line
@@ -583,6 +583,7 @@ struct l2cap_conn { 


	struct list_head	chan_l;

	struct mutex		chan_lock;

	struct kref		ref;

};



#define L2CAP_INFO_CL_MTU_REQ_SENT	0x01
@@ -813,4 +814,7 @@ void l2cap_logical_cfm(struct l2cap_chan *chan, struct hci_chan *hchan, 
		       u8 status);

void __l2cap_physical_cfm(struct l2cap_chan *chan, int result);



void l2cap_conn_get(struct l2cap_conn *conn);

void l2cap_conn_put(struct l2cap_conn *conn);



#endif /* __L2CAP_H */

net/bluetooth/l2cap_core.c

+24 −1
Original line number Diff line number Diff line
@@ -1486,7 +1486,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 
	}



	hcon->l2cap_data = NULL;

	kfree(conn);

	conn->hchan = NULL;

	l2cap_conn_put(conn);

}



static void security_timeout(struct work_struct *work)
@@ -1520,8 +1521,10 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) 
		return NULL;

	}



	kref_init(&conn->ref);

	hcon->l2cap_data = conn;

	conn->hcon = hcon;

	hci_conn_get(conn->hcon);

	conn->hchan = hchan;



	BT_DBG("hcon %p conn %p hchan %p", hcon, conn, hchan);
@@ -1558,6 +1561,26 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) 
	return conn;

}



static void l2cap_conn_free(struct kref *ref)

{

	struct l2cap_conn *conn = container_of(ref, struct l2cap_conn, ref);



	hci_conn_put(conn->hcon);

	kfree(conn);

}



void l2cap_conn_get(struct l2cap_conn *conn)

{

	kref_get(&conn->ref);

}

EXPORT_SYMBOL(l2cap_conn_get);



void l2cap_conn_put(struct l2cap_conn *conn)

{

	kref_put(&conn->ref, l2cap_conn_free);

}

EXPORT_SYMBOL(l2cap_conn_put);



/* ---- Socket interface ---- */



/* Find socket with psm and source / destination bdaddr.