While l2cap_user callbacks are running, the whole hci_dev is locked. Even
if we would add more fine-grained locking to HCI core, it would still be
called from the non-reentrant rx work-queue and thus block the event
processing.

However, if we want to perform synchronous I/O during HID device
registration (eg., to perform device-detection), we need the HCI core
to be able to dispatch incoming data.

Therefore, we now move device-registration to a separate worker. The HCI
core can continue running and we add devices asynchronously in another
kernel thread. Device removal is synchronized and waits for the worker
to exit before calling the usual device removal functions.

If l2cap_user->remove is called before the thread registered the devices,
we set "terminate" to true and the thread will skip it. If
l2cap_user->remove is called after it, we notice this as the device
is no longer in HIDP_SESSION_PREPARING state and simply unregister the
device as we did before.
There is no new deadlock as we now call hidp_session_add_dev() with
one lock less held (the HCI lock) and it cannot itself call back into
HCI as it was called with the HCI-lock held before.

One might wonder whether this can block during device unregistration.
But we set "terminate" to true and wake the HIDP thread up _before_
unregistering the HID/input devices. Therefore, all pending HID I/O
operations are canceled. All further I/O attempts will fail with ENODEV
or EIO. So all latency we can get are few context-switches, but no
timeouts or blocking I/O waits!

This change also prepares for a long standing HID bug. All HID devices
that register power_supply devices need to be able to handle callbacks
during registration (a power_supply oddity that cannot easily be fixed).
So with this patch available, we can allow HID I/O during registration
by calling the recently introduced hid_device_io_start/stop helpers,
which currently are a no-op for bluetooth due to this locking.

Note that we cannot do the same for input devices. input-core doesn't
allow us to call input_event() asynchronously to input_register_device(),
which HID-core kindly allows (for good reasons).
Fixing input-core to allow this isn't as easy as it sounds and is,
beside simplifying HIDP, not really an improvement. Hence, we still
register input devices synchronously as we did before. Only HID devices
are registered asynchronously.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Acked-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Tested-by: NDaniel Nicoletti <dantti12@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

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: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

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: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

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: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

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: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Partial revert of commit aabf6f89. When the hidp session thread
was converted from kernel_thread to kthread, the atomic/wakeups
were replaced with kthread_stop. kthread_stop has blocking semantics
which are inappropriate for the hidp session kthread. In addition,
the kthread signals itself to terminate in hidp_process_hid_control()
- it cannot do this with kthread_stop().

Lastly, a wakeup can be lost if the wakeup happens between checking
for the loop exit condition and setting the current state to
TASK_INTERRUPTIBLE. (Without appropriate synchronization mechanisms,
the task state should not be changed between the condition test and
the yield - via schedule() - as this creates a race between the
wakeup and resetting the state back to interruptible.)
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Signed-off-by: NAntonio Ospite <ospite@studenti.unina.it>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

kernel_thread() is a low-level implementation detail and
EXPORT_SYMBOL(kernel_thread) is scheduled for removal.
Use the <linux/kthread.h> API instead.
Signed-off-by: NSzymon Janc <szymon.janc@tieto.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Signed-off-by: NSzymon Janc <szymon.janc@tieto.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

This patch adds support or getting and setting feature reports for bluetooth
HID devices from HIDRAW.
Signed-off-by: NAlan Ott <alan@signal11.us>
Acked-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Wait for an ACK from the device before returning from
hidp_output_raw_report(). This way, failures can be returned to the user
application. Also, it prevents ACK/NAK packets from an output packet from
being confused with ACK/NAK packets from an input request packet.
Signed-off-by: NAlan Ott <alan@signal11.us>
Acked-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Move the call to hid_add_device() (which calls a device's probe() function)
to after the kernel_thread() call which starts the hidp_session() thread.
This ensures the Bluetooth receive socket is fully running by the time a
device's probe() function is called. This way, a device can communicate
(send and receive) with the Bluetooth device from its probe() function.
Signed-off-by: NAlan Ott <alan@signal11.us>
Acked-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Define a new function to return the waitqueue of a "struct sock".

static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
	return sk->sk_sleep;
}

Change all read occurrences of sk_sleep by a call to this function.

Needed for a future RCU conversion. sk_sleep wont be a field directly
available.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The report descriptor is read by user space (via the Service
Discovery Protocol), so it is only available during the ioctl
to connect. However, the HID probe function that needs the
descriptor might not be called until a specific module is
loaded. Keep a copy of the descriptor so it is available for
later use.
Signed-off-by: NMichael Poole <mdpoole@troilus.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The core exports the hci_conn_hold_device() and hci_conn_put_device()
functions for device reference of connections. Use this to ensure that
the uevents from the parent are send after the child ones.

Based on a report by Brian Rogers <brian@xyzw.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Next step for complete hid bus, this patch includes:
- call parser either from probe or from hid-core if there is no probe.
- add ll_driver structure and centralize some stuff there (open, close...)
- split and merge usb_hid_configure and hid_probe into several functions
  to allow hooks/fixes between them
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

This patch extends the current Bluetooth HID support to use the new
HID subsystem and adds full report mode support.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!