Bluetooth: Use separate function for BCM92035 vendor setup

Trying to squeeze every single vendor setup routine into the same function
and have it assigned all the time is actually a bad idea. Especially since
the core can handle the absence of a setup routine perfectly fine.

To make this a lot simpler for future additions of vendor setup code,
split the BCM92035 setup into its own function and only assign it when
this specific device has been detected.

Doing it like this has the nice side benefit that we do not have to keep
a copy of the driver_info around.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: rename hci_conn_put to hci_conn_drop

We use _get() and _put() for device ref-counting in the kernel. However,
hci_conn_put() is _not_ used for ref-counting, hence, rename it to
hci_conn_drop() so we can later fix ref-counting and introduce
hci_conn_put().

hci_conn_hold() and hci_conn_put() are currently used to manage how long a
connection should be held alive. When the last user drops the connection,
we spawn a delayed work that performs the disconnect. Obviously, this has
nothing to do with ref-counting for the _object_ but rather for the
keep-alive of the connection.

But we really _need_ proper ref-counting for the _object_ to allow
connection-users like rfcomm-tty, HIDP or others.

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>
Bluetooth: Fix SCO connection reference

This patch fixes decrementing SCO connection reference right after
stablishing the SCO connection with defer setup enabled. The dump below
shows a disconnection command with handle 0, the connection is still in
BT_CONNECT2 state and there isn't a handle associated with it.

< HCI Command: Accept Synchronous Connection (0x01|0x0029) plen 21
  bdaddr 78:47:1D:B3:72:6C
> HCI Event: Command Status (0x0f) plen 4
  Accept Synchronous Connection (0x01|0x0029) status 0x00 ncmd 1
< HCI Command: Disconnect (0x01|0x0006) plen 3
  handle 0 reason 0x13
  Reason: Remote User Terminated Connection
> HCI Event: Command Status (0x0f) plen 4
  Disconnect (0x01|0x0006) status 0x00 ncmd 1
> HCI Event: Synchronous Connect Complete (0x2c) plen 17
  status 0x00 handle 46 bdaddr 78:47:1D:B3:72:6C
  type eSCO
  Air mode: CVSD
< SCO data: handle 46 flags 0x00 dlen 48

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: Use GFP_KERNEL in sco_conn_add

This patch changes the memory allocation flags in the sco_conn_add
function, replacing the type to GFP_KERNEL. This function is executed
in process context and it is not called inside an atomic section.

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: Minor coding style fix

This patch removes unneeded initialization and empty line.

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: Remove unneeded parameter

This patch removes the status parameter of the l2cap_conn_add function.
The parameter 'status' is always 0.

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: Reject SCO when hci connection timeouts

This patch sends Reject Synchronous Connection Request Command when
hci_conn_timeout is triggered, and the SCO connection is in BT_CONNECT2
state. It prevents inconsistency if the remote host doesn't implement
properly the timeout for the connection request, and it removes the
connection reference left when the socket is closed for incoming SCO
connections.

[ 2650.129080] sco_sock_release: sock ffff8801ca417400, sk ffff88020c408800
[ 2650.129092] sco_sock_clear_timer: sock ffff88020c408800 state 6
[ 2650.129101] __sco_sock_close: sk ffff88020c408800 state 6 socket
	ffff8801ca417400
[ 2650.129108] sco_chan_del: sk ffff88020c408800, conn ffff8801c650ea20,
	err 104
[ 2650.129114] hci_conn_put: hcon ffff88020c40a800 orig refcnt 1
[ 2650.129128] sco_sock_kill: sk ffff88020c408800 state 9
[ 2650.129135] sco_sock_destruct: sk ffff88020c408800
[ 2650.138468] hci_conn_timeout: hcon ffff88020c40a800 state BT_CONNECT2

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Bluetooth: remove unneeded hci_conn_hold/put_device()

hci_conn_hold/put_device() is used to control when hci_conn->dev is no
longer needed and can be deleted from the system. Lets first look how they
are currently used throughout the code (excluding HIDP!).

All code that uses hci_conn_hold_device() looks like this:
    ...
    hci_conn_hold_device();
    hci_conn_add_sysfs();
    ...
On the other side, hci_conn_put_device() is exclusively used in
hci_conn_del().

So, considering that hci_conn_del() must not be called twice (which would
fail horribly), we know that hci_conn_put_device() is only called _once_
(which is in hci_conn_del()).
On the other hand, hci_conn_add_sysfs() must not be called twice, either
(it would call device_add twice, which breaks the device, see
drivers/base/core.c). So we know that hci_conn_hold_device() is also
called only once (it's only called directly before hci_conn_add_sysfs()).

So hold and put are known to be called only once. That means we can safely
remove them and directly call hci_conn_del_sysfs() in hci_conn_del().

But there is one issue left: HIDP also uses hci_conn_hold/put_device().
However, this case can be ignored and simply removed as it is totally
broken. The issue is, the only thing HIDP delays with
hci_conn_hold_device() is the removal of the hci_conn->dev from sysfs.
But, the hci_conn device has no mechanism to get notified when its own
parent (hci_dev) gets removed from sysfs. hci_dev_hold/put() does _not_
control when it is removed but only when the device object is created
and destroyed.
And hci_dev calls hci_conn_flush_*() when it removes itself from sysfs,
which itself causes hci_conn_del() to be called, but it does _not_ cause
hci_conn_del_sysfs() to be called, which is wrong.

Hence, we fix it to call hci_conn_del_sysfs() in hci_conn_del(). This
guarantees that a hci_conn object is removed from sysfs _before_ its
parent hci_dev is removed.

The changes to HIDP look scary, wrong and broken. However, if you look at
the HIDP session management, you will notice they're already broken in the
exact _same_ way (ever tried "unplugging" HIDP devices? Breaks _all_ the
time).
So this patch only makes HIDP look _scary_ and _obviously broken_. It does
not break HIDP itself, it already is!

See later patches in this series which fix HIDP to use proper
session-management.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: introduce hci_conn ref-counting

We currently do not allow using hci_conn from outside of HCI-core.
However, several other users could make great use of it. This includes
HIDP, rfcomm and all other sub-protocols that rely on an active
connection.

Hence, we now introduce hci_conn ref-counting. We currently never call
get_device(). put_device() is exclusively used in hci_conn_del_sysfs().
Hence, we currently never have a greater device-refcnt than 1.
Therefore, it is safe to move the put_device() call from
hci_conn_del_sysfs() to hci_conn_del() (it's the only caller). In fact,
this even fixes a "use-after-free" bug as we access hci_conn after calling
hci_conn_del_sysfs() in hci_conn_del().

From now on we can add references to hci_conn objects in other layers
(like l2cap_sock, HIDP, rfcomm, ...) and grab a reference via
hci_conn_get(). This does _not_ guarantee, that the connection is still
alive. But, this isn't what we want. We can simply lock the hci_conn
device and use "device_is_registered(hci_conn->dev)" to test that.
However, this is hardly necessary as outside users should never rely on
the HCI connection to be alive, anyway. Instead, they should solely rely
on the device-object to be available.
But if sub-devices want the hci_conn object as sysfs parent, they need to
be notified when the connection drops. This will be introduced in later
patches with l2cap_users.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: remove unused session->state field

This field is always BT_CONNECTED. Remove it and set it to BT_CONNECTED in
hidp_copy_session() unconditionally.

Also note that this field is totally bogus. Userspace can query an
hidp-session for its state. However, whenever user-space queries us, this
field should be BT_CONNECTED. If it wasn't BT_CONNECTED, then we would be
currently cleaning up the session and the session itself would exit in the
next few milliseconds. Hence, there is no reason to let user-space know
that the session will exit now if they cannot make _any_ use of that.

Thus, remove the field and let user-space think that a session is always
BT_CONNECTED as long as they can query it.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: allow constant arguments for bacmp()/bacpy()

There is no reason to require the source arguments to be writeable so fix
this to allow constant source addresses.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: test "terminate" before sleeping

The "terminate" flag is guaranteed to be set before the session terminates
and the handlers are woken up. Hence, we need to add it to the
sleep-condition.

Note that testing the flags is not enough as nothing prevents us from
setting the flags again after the session-handler terminated.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: move hidp_schedule() to core.c

There is no reason to keep this helper in the header file. No other file
depends on it so move it into hidp/core.c where it belongs.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
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: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: l2cap: add l2cap_user sub-modules

Several sub-modules like HIDP, rfcomm, ... need to track l2cap
connections. The l2cap_conn->hcon->dev object is used as parent for sysfs
devices so the sub-modules need to be notified when the hci_conn object is
removed from sysfs.

As submodules normally use the l2cap layer, the l2cap_user objects are
registered there instead of on the underlying hci_conn object. This avoids
any direct dependency on the HCI layer and lets the l2cap core handle any
specifics.

This patch introduces l2cap_user objects which contain a "probe" and
"remove" callback. You can register them on any l2cap_conn object and if
it is active, the "probe" callback will get called. Otherwise, an error is
returned.

The l2cap_conn object will call your "remove" callback directly before it
is removed from user-space. This allows you to remove your submodules
_before_ the parent l2cap_conn and hci_conn object is removed.

At any time you can asynchronously unregister your l2cap_user object if
your submodule vanishes before the l2cap_conn object does.

There is no way around l2cap_user. If we want wire-protocols in the
kernel, we always want the hci_conn object as parent in the sysfs tree. We
cannot use a channel here since we might need multiple channels for a
single protocol.
But the problem is, we _must_ get notified when an l2cap_conn object is
removed. We cannot use reference-counting for object-removal! This is not
how it works. If a hardware is removed, we should immediately remove the
object from sysfs. Any other behavior would be inconsistent with the rest
of the system. Also note that device_del() might sleep, but it doesn't
wait for user-space or block very long. It only _unlinks_ the object from
sysfs and the whole device-tree. Everything else is handled by ref-counts!
This is exactly what the other sub-modules must do: unlink their devices
when the "remove" l2cap_user callback is called. They should not do any
cleanup or synchronous shutdowns.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: add new session-management helpers

This is a rewrite of the HIDP session management. It implements HIDP as an
l2cap_user sub-module so we get proper notification when the underlying
connection goes away.

The helpers are not yet used but only added in this commit. The old
session management is still used and will be removed in a following patch.

The old session-management was flawed. Hotplugging is horribly broken and
we have no way of getting notified when the underlying connection goes
down. The whole idea of removing the HID/input sub-devices from within the
session itself is broken and suffers from major dead-locks. We never can
guarantee that the session can unregister itself as long as we use
synchronous shutdowns. This can only work with asynchronous shutdowns.
However, in this case we _must_ be able to unregister the session from the
outside as otherwise the l2cap_conn object might be unlinked before we
are.

The new session-management is based on l2cap_user. There is only one
way how to add a session and how to delete a session: "probe" and "remove"
callbacks from l2cap_user.
This guarantees that the session can be registered and unregistered at
_any_ time without any synchronous shutdown.
On the other hand, much work has been put into proper session-refcounting.
We can unregister/unlink the session only if we can guarantee that it will
stay alive. But for asynchronous shutdowns we never know when the last
user goes away so we must use proper ref-counting.

The old ->conn field has been renamed to ->hconn so we can reuse ->conn in
the new session management. No other existing HIDP code is modified.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: remove old session-management

We have the full new session-management now available so lets switch over
and remove all the old code. Few semantics changed, so we need to adjust
the sock.c callers a bit. But this mostly simplifies the logic.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: handle kernel_sendmsg() errors correctly

We shouldn't push back the skbs if kernel_sendmsg() fails. Instead, we
terminate the connection and drop the skb. Only on EAGAIN we push it back
and return.
l2cap doesn't return EAGAIN, yet, but this guarantees we're safe if it
will at some time in the future.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: merge hidp_process_{ctrl,intr}_transmit()

Both hidp_process_ctrl_transmit() and hidp_process_intr_transmit() are
exactly the same apart from the transmit-queue and socket pointers.
Therefore, pass them as argument and merge both functions into one so we
avoid 25 lines of code-duplication.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hidp: merge 'send' functions into hidp_send_message()

We handle skb buffers all over the place, even though we have
hidp_send_*_message() helpers. This creates a more generic
hidp_send_message() helper and uses it instead of dealing with transmit
queues directly everywhere.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>