diff options
| -rw-r--r-- | include/net/bluetooth/l2cap.h | 15 | ||||
| -rw-r--r-- | net/bluetooth/l2cap_sock.c | 9 | ||||
| -rw-r--r-- | net/bluetooth/smp.c | 10 |
3 files changed, 33 insertions, 1 deletions
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index ead99f032f7a..061e648052c8 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -28,6 +28,7 @@ #define __L2CAP_H #include <asm/unaligned.h> +#include <linux/atomic.h> /* L2CAP defaults */ #define L2CAP_DEFAULT_MTU 672 @@ -481,6 +482,7 @@ struct l2cap_chan { struct hci_conn *hs_hcon; struct hci_chan *hs_hchan; struct kref kref; + atomic_t nesting; __u8 state; @@ -713,6 +715,17 @@ enum { FLAG_HOLD_HCI_CONN, }; +/* Lock nesting levels for L2CAP channels. We need these because lockdep + * otherwise considers all channels equal and will e.g. complain about a + * connection oriented channel triggering SMP procedures or a listening + * channel creating and locking a child channel. + */ +enum { + L2CAP_NESTING_SMP, + L2CAP_NESTING_NORMAL, + L2CAP_NESTING_PARENT, +}; + enum { L2CAP_TX_STATE_XMIT, L2CAP_TX_STATE_WAIT_F, @@ -778,7 +791,7 @@ void l2cap_chan_put(struct l2cap_chan *c); static inline void l2cap_chan_lock(struct l2cap_chan *chan) { - mutex_lock(&chan->lock); + mutex_lock_nested(&chan->lock, atomic_read(&chan->nesting)); } static inline void l2cap_chan_unlock(struct l2cap_chan *chan) diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index ad1cf82fee02..f1a51564b8fd 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -285,6 +285,12 @@ static int l2cap_sock_listen(struct socket *sock, int backlog) sk->sk_max_ack_backlog = backlog; sk->sk_ack_backlog = 0; + /* Listening channels need to use nested locking in order not to + * cause lockdep warnings when the created child channels end up + * being locked in the same thread as the parent channel. + */ + atomic_set(&chan->nesting, L2CAP_NESTING_PARENT); + chan->state = BT_LISTEN; sk->sk_state = BT_LISTEN; @@ -1497,6 +1503,9 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent) l2cap_chan_set_defaults(chan); } + /* Set default lock nesting level */ + atomic_set(&chan->nesting, L2CAP_NESTING_NORMAL); + /* Default config options */ chan->flush_to = L2CAP_DEFAULT_FLUSH_TO; diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index 3d38553eb526..3b63c7f09dd5 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -1658,6 +1658,13 @@ static inline struct l2cap_chan *smp_new_conn_cb(struct l2cap_chan *pchan) chan->omtu = pchan->omtu; chan->mode = pchan->mode; + /* Other L2CAP channels may request SMP routines in order to + * change the security level. This means that the SMP channel + * lock must be considered in its own category to avoid lockdep + * warnings. + */ + atomic_set(&chan->nesting, L2CAP_NESTING_SMP); + BT_DBG("created chan %p", chan); return chan; @@ -1715,6 +1722,9 @@ int smp_register(struct hci_dev *hdev) chan->imtu = L2CAP_DEFAULT_MTU; chan->ops = &smp_root_chan_ops; + /* Set correct nesting level for a parent/listening channel */ + atomic_set(&chan->nesting, L2CAP_NESTING_PARENT); + hdev->smp_data = chan; return 0; |