This patch upadate the user confirm and user passkey mgmt messages to
match the latest API specification by adding an address type parameter
to them.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds an address type parameter to the disconnect command and
response in order to match the latest mgmt API specification.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch renames the mgmt_remove_keys command to mgmt_unpair_device
and updates its parameters to match the latest API (specifically, it
adds an address type parameter to the command and its response).
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

We are not supposed to block in start_discovery() because
start_discovery code is running in write() syscall context
and this would block the write operation on the mgmt socket.
This way, we cannot directly call hci_do_le_scan() to scan
LE devices in start_discovery(). To overcome this issue a
derefered work (hdev->le_scan) was created so we can properly
call hci_do_le_scan().

The helper function hci_le_scan() simply set LE scan parameters
and queue hdev->le_scan work. The work is queued on system_long_wq
since it can sleep for a few seconds in the worst case (timeout).
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This patch adds to hci_core the hci_do_le_scan function which
should be used to scan LE devices.

In order to enable LE scan, hci_do_le_scan() sends commands (Set
LE Scan Parameters and Set LE Scan Enable) to the controller and
waits for its results. If commands were executed successfully a
delayed work is scheduled to disable the ongoing scanning after
some amount of time. This function blocks.
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Send MGMT Discovering events once LE scan starts/stops so the
userspace can track when local adapters are discovering LE devices.

This way, we also keep the same behavior of inquiry which sends MGMT
Discovering events once inquiry starts/stops even if it is triggered
by an external tool (e.g. hcitool).
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

With the use of the new structures and lists for the SMP LTK's
we may remove some code that is now unused. No need to have extra
fields of information inside link_key now that it is only used
for Link Keys.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This adds a method to notify that a new LTK is available and
a handler to store keys coming from userspace into the kernel LTK
list.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This updates all the users of the older way, that was using the
link_keys list to store the SMP keys, to use the new way.

This includes defining new types for the keys, we have a type for each
combination of STK/LTK and Master/Slave.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This includes a new list for storing the keys and a new structure used
to represent each key.

Some notes: authenticated is used to identify that the key may be used
to setup a HIGH security link. As the same list is used to store both
the STK's and the LTK's the type field is used so we can separate
between those two types of keys and if the key should be used when
in the master or slave role.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This patch implements the Cancel Pair Device command for mgmt. It's used
by user space to cancel an ongoing pairing attempt which was triggered
by the Pair Device command.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch updates the opcodes for mgmt commands and events to match the
latest user space API specification.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This makes clear that this is the size of the key used to
encrypt the link.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This defines two new messages, one event that will inform
userspace that a new Long Term Key was exchanged and one that
will allow userspace to load LTKs into the kernel.

Besides the information necessary for the restablishement of
the secure link, we added some extra information: "authenticated"
that informs if the key can be used to establish an authenticated
link, and "master" that informs the role in that the key should
be used.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

__cancel_delayed_work() is being used in some paths where we cannot
sleep waiting for the delayed work to finish. However, that function
might return while the timer is running and the work will be queued
again. Replace the calls with safer cancel_delayed_work() version
which spins until the timer handler finishes on other CPUs and
cancels the delayed work.
Signed-off-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

We don't need to use the _sync variant in hci_conn_hold and
hci_conn_put to cancel conn->disc_work delayed work. This way
we avoid potential deadlocks like this one reported by lockdep.

======================================================
[ INFO: possible circular locking dependency detected ]
3.2.0+ #1 Not tainted
-------------------------------------------------------
kworker/u:1/17 is trying to acquire lock:
 (&hdev->lock){+.+.+.}, at: [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]

but task is already holding lock:
 ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 ((&(&conn->disc_work)->work)){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff81034ed1>] wait_on_work+0x3d/0xaa
       [<ffffffff81035b54>] __cancel_work_timer+0xac/0xef
       [<ffffffff81035ba4>] cancel_delayed_work_sync+0xd/0xf
       [<ffffffffa00554b0>] smp_chan_create+0xde/0xe6 [bluetooth]
       [<ffffffffa0056160>] smp_conn_security+0xa3/0x12d [bluetooth]
       [<ffffffffa0053640>] l2cap_connect_cfm+0x237/0x2e8 [bluetooth]
       [<ffffffffa004239c>] hci_proto_connect_cfm+0x2d/0x6f [bluetooth]
       [<ffffffffa0046ea5>] hci_event_packet+0x29d1/0x2d60 [bluetooth]
       [<ffffffffa003dde3>] hci_rx_work+0xd0/0x2e1 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

-> #1 (slock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e553a>] _raw_spin_lock_bh+0x36/0x6a
       [<ffffffff81244d56>] lock_sock_nested+0x24/0x7f
       [<ffffffffa004d96f>] lock_sock+0xb/0xd [bluetooth]
       [<ffffffffa0052906>] l2cap_chan_connect+0xa9/0x26f [bluetooth]
       [<ffffffffa00545f8>] l2cap_sock_connect+0xb3/0xff [bluetooth]
       [<ffffffff81243b48>] sys_connect+0x69/0x8a
       [<ffffffff812e6579>] system_call_fastpath+0x16/0x1b

-> #0 (&hdev->lock){+.+.+.}:
       [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
       [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
       [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

other info that might help us debug this:

Chain exists of:
  &hdev->lock --> slock-AF_BLUETOOTH-BTPROTO_L2CAP --> (&(&conn->disc_work)->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((&(&conn->disc_work)->work));
                               lock(slock-AF_BLUETOOTH-BTPROTO_L2CAP);
                               lock((&(&conn->disc_work)->work));
  lock(&hdev->lock);

 *** DEADLOCK ***

2 locks held by kworker/u:1/17:
 #0:  (hdev->name){.+.+.+}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf
 #1:  ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

stack backtrace:
Pid: 17, comm: kworker/u:1 Not tainted 3.2.0+ #1
Call Trace:
 [<ffffffff812e06c6>] print_circular_bug+0x1f8/0x209
 [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
 [<ffffffff81021ef2>] ? arch_local_irq_restore+0x6/0xd
 [<ffffffff81022bc7>] ? vprintk+0x3f9/0x41e
 [<ffffffff81057444>] lock_acquire+0x8a/0xa7
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff81190fd6>] ? __dynamic_pr_debug+0x6d/0x6f
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff8105320f>] ? trace_hardirqs_off+0xd/0xf
 [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
 [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff810357af>] process_one_work+0x178/0x2bf
 [<ffffffff81035751>] ? process_one_work+0x11a/0x2bf
 [<ffffffff81055af3>] ? lock_acquired+0x1d0/0x1df
 [<ffffffffa00410f3>] ? hci_acl_disconn+0x65/0x65 [bluetooth]
 [<ffffffff81036178>] worker_thread+0xce/0x152
 [<ffffffff810407ed>] ? finish_task_switch+0x45/0xc5
 [<ffffffff810360aa>] ? manage_workers.isra.25+0x16a/0x16a
 [<ffffffff81039a03>] kthread+0x95/0x9d
 [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10
 [<ffffffff812e5db4>] ? retint_restore_args+0x13/0x13
 [<ffffffff8103996e>] ? __init_kthread_worker+0x55/0x55
 [<ffffffff812e7750>] ? gs_change+0x13/0x13
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@openbossa.org>
Reviewed-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Add channel-specific skb allocation method
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

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: NOctavian Purdila <octavian.purdila@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

It's a very common test to see if both the local and the remote device
have SSP enabled. By creating a simple function to test this we can
shorten many if-statements in the code.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

The ssp_mode is essentially just a boolean so it's more appropriate to
have it simply as a flag in hdev->dev_flags.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

Now that the flags member of struct hci_conn is supposed to accommodate
any boolean type values we can easily merge all boolean members into it.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch updates mgmt_ev_device_connected and mgmt_ev_device found to
include an EIR-encoded remote name and class whenever possible. With
this addition the mgmt_ev_remote_name event becomes unnecessary and can
be removed. Since the connected event doesn't map to hci_conn_complete
anymore a HCI_CONN_MGMT_CONNECTED flag is added to track when mgmt has
been notified about a connection.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

The hdev->out variable is essentially a boolean so the type 'bool' makes
more sense than u8.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

These flags can and will be used for more general purpose values than
just pending state transitions so the more common name "flags" makes
more sense than "pend".
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

There's no need to have a separate device class field since the same
information can be encoded into the EIR data.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This makes the function accessible from all places it's needed (e.g.
mgmt.c and hci_event.c).
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds missing EIR defines (as specified in the Bluetooth
Assigned Numbers document) to hci.h.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch add a two byte eir_len parameter mgmt_ev_device_found. Since
it's unlikely that the data will in the short term be much bigger than
conventional EIR lengths just use a small stack based buffer for now to
avoid dynamic memory allocation & freeing.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

User space uses device_(dis)connected instead of just (dis)connected so
rename the defines and functions to match this.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds a new parameter to mgmt_device_found() to inform
the length of 'eir' pointer.

EIR data from LE advertising report event doesn't have a fixed length
as EIR data from extended inquiry result event does. We needed to
change mgmt_device_found() so it copies 'eir_len' bytes instead of
HCI_MAX_EIR_LENGTH.
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This is usefull when need to make action after timer was cleared
depending on if it was running or not.
Signed-off-by: NSzymon Janc <szymon.janc@tieto.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Fix the following build warning:

  CC [M]  net/bluetooth/hci_core.o
net/bluetooth/hci_core.c: In function ‘__check_enable_hs’:
net/bluetooth/hci_core.c:2587: warning: return from incompatible pointer type

module_param in hci_core.c passes 'enable_hs' as bool format, so fix
this variable definition type.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This patch makes sure that devices with stronger signal (RSSI closer to
0) are sorted first in the resolve list and will therefore get their
names resolved first during device discovery. Since it's more likely
that the device the user is trying to discover has a strong signal due
to its proximity this ensures that the user gets the "device found"
event for it more quickly.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

There's no point in exposing these to user-space (which is what happens
to everything in hdev->flags) so move them to dev_flags instead.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

As reported by Dan Carpenter this function causes a Sparse warning and
shouldn't be declared inline:

include/net/bluetooth/l2cap.h:837:30 error: marked inline, but without a
definition"
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

Since we remove the owner field of hci_dev hci_dev_put and __hci_dev_put
do the same so we can merge them into one function. Same for
hci_dev_hold and __hci_dev_hold.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The hci_dev->dev device structure has an internal refcount. This
refcount is used to protect the whole hci_dev object. However, we
currently do not use it.  Therefore, if someone calls hci_free_dev() we
currently immediately destroy the hci_dev object because we never took
the device refcount.

This even happens if the hci_dev->refcnt is not 0. In fact, the
hci_dev->refcnt is totally useless in its current state. Therefore, we
simply remove hci_dev->refcnt and instead use hci_dev->dev refcnt.

This fixes all the symptoms and also correctly integrates the device
structure into our bluetooth bus system.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

After unregistering an hci_dev object a bluetooth driver does not have
any callbacks in the hci_dev structure left over. Therefore, there is no
need to keep a reference to the module.

Previously, we needed this to protect the hci-destruct callback.
However, this callback is no longer available so we do not need this
owner field, anymore.  Drivers now call hci_unregister_dev() and they
are done with the object.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The hci-destruct callback is not used by any driver so we can remove it.
There is no reason to keep it alive, anymore. Drivers can free their
internal data on driver-release and we do not need to provide a public
destruct callback.

Internally, we still use a destruct callback inside of hci_sysfs.c. This
one is used to correctly free our hci_dev data structure if no more
users have a reference to it.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Several drivers already provide an empty callback so we can actually
make this optional and then remove all those empty callbacks in the
drivers.

This callback isn't needed at all by most drivers as they can remove
their allocated structures on device disconnect and not on hci
destruction.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>