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Bluetooth: l2cap: introduce l2cap_conn ref-counting

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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: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
This commit is contained in:
David Herrmann 2013-04-06 20:28:44 +02:00 committed by Gustavo Padovan
parent 3764eaa922
commit 9c903e373c
2 changed files with 28 additions and 1 deletions
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4
include/net/bluetooth/l2cap.h
View File

@ -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 */

25
net/bluetooth/l2cap_core.c
View File

@ -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.