Bluetooth: silence lockdep warning

Since bluetooth uses multiple protocols types, to avoid lockdep
warnings, we need to use different lockdep classes (one for each
protocol type).

This is already done in bt_sock_create but it misses a couple of cases
when new connections are created. This patch corrects that to fix the
following warning:

<4>[ 1864.732366] =======================================================
<4>[ 1864.733030] [ INFO: possible circular locking dependency detected ]
<4>[ 1864.733544] 3.0.16-mid3-00007-gc9a0f62 #3
<4>[ 1864.733883] -------------------------------------------------------
<4>[ 1864.734408] t.android.btclc/4204 is trying to acquire lock:
<4>[ 1864.734869]  (rfcomm_mutex){+.+.+.}, at: [<c14970ea>] rfcomm_dlc_close+0x15/0x30
<4>[ 1864.735541]
<4>[ 1864.735549] but task is already holding lock:
<4>[ 1864.736045]  (sk_lock-AF_BLUETOOTH){+.+.+.}, at: [<c1498bf7>] lock_sock+0xa/0xc
<4>[ 1864.736732]
<4>[ 1864.736740] which lock already depends on the new lock.
<4>[ 1864.736750]
<4>[ 1864.737428]
<4>[ 1864.737437] the existing dependency chain (in reverse order) is:
<4>[ 1864.738016]
<4>[ 1864.738023] -> #1 (sk_lock-AF_BLUETOOTH){+.+.+.}:
<4>[ 1864.738549]        [<c1062273>] lock_acquire+0x104/0x140
<4>[ 1864.738977]        [<c13d35c1>] lock_sock_nested+0x58/0x68
<4>[ 1864.739411]        [<c1493c33>] l2cap_sock_sendmsg+0x3e/0x76
<4>[ 1864.739858]        [<c13d06c3>] __sock_sendmsg+0x50/0x59
<4>[ 1864.740279]        [<c13d0ea2>] sock_sendmsg+0x94/0xa8
<4>[ 1864.740687]        [<c13d0ede>] kernel_sendmsg+0x28/0x37
<4>[ 1864.741106]        [<c14969ca>] rfcomm_send_frame+0x30/0x38
<4>[ 1864.741542]        [<c1496a2a>] rfcomm_send_ua+0x58/0x5a
<4>[ 1864.741959]        [<c1498447>] rfcomm_run+0x441/0xb52
<4>[ 1864.742365]        [<c104f095>] kthread+0x63/0x68
<4>[ 1864.742742]        [<c14d5182>] kernel_thread_helper+0x6/0xd
<4>[ 1864.743187]
<4>[ 1864.743193] -> #0 (rfcomm_mutex){+.+.+.}:
<4>[ 1864.743667]        [<c1061ada>] __lock_acquire+0x988/0xc00
<4>[ 1864.744100]        [<c1062273>] lock_acquire+0x104/0x140
<4>[ 1864.744519]        [<c14d2c70>] __mutex_lock_common+0x3b/0x33f
<4>[ 1864.744975]        [<c14d303e>] mutex_lock_nested+0x2d/0x36
<4>[ 1864.745412]        [<c14970ea>] rfcomm_dlc_close+0x15/0x30
<4>[ 1864.745842]        [<c14990d9>] __rfcomm_sock_close+0x5f/0x6b
<4>[ 1864.746288]        [<c1499114>] rfcomm_sock_shutdown+0x2f/0x62
<4>[ 1864.746737]        [<c13d275d>] sys_socketcall+0x1db/0x422
<4>[ 1864.747165]        [<c14d42f0>] syscall_call+0x7/0xb

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

net/bluetooth/l2cap_sock.c

@@ -849,6 +849,8 @@ static struct l2cap_chan *l2cap_sock_new_connection_cb(void *data)
 	if (!sk)
 		return NULL;
 
+	bt_sock_reclassify_lock(sk, BTPROTO_L2CAP);
+
 	l2cap_sock_init(sk, parent);
 
 	return l2cap_pi(sk)->chan;