When processing a RFCOMM UA frame when the socket is closed and we were
not the RFCOMM initiator would cause rfcomm_session_put() to be called
twice during rfcomm_process_rx(). This would cause a kernel panic in
rfcomm_session_close() then.

This could be easily reproduced during disconnect with devices such as
Motorola H270 that send RFCOMM UA followed quickly by L2CAP disconnect
request. This trace for this looks like:

2009-09-21 17:22:37.788895 < ACL data: handle 1 flags 0x02 dlen 8
   L2CAP(d): cid 0x0041 len 4 [psm 3]
     RFCOMM(s): DISC: cr 0 dlci 20 pf 1 ilen 0 fcs 0x7d
2009-09-21 17:22:37.906204 > HCI Event: Number of Completed Packets (0x13) plen 5
   handle 1 packets 1
2009-09-21 17:22:37.933090 > ACL data: handle 1 flags 0x02 dlen 8
   L2CAP(d): cid 0x0040 len 4 [psm 3]
     RFCOMM(s): UA: cr 0 dlci 20 pf 1 ilen 0 fcs 0x57
2009-09-21 17:22:38.636764 < ACL data: handle 1 flags 0x02 dlen 8
   L2CAP(d): cid 0x0041 len 4 [psm 3]
     RFCOMM(s): DISC: cr 0 dlci 0 pf 1 ilen 0 fcs 0x9c
2009-09-21 17:22:38.744125 > HCI Event: Number of Completed Packets (0x13) plen 5
   handle 1 packets 1
2009-09-21 17:22:38.763687 > ACL data: handle 1 flags 0x02 dlen 8
   L2CAP(d): cid 0x0040 len 4 [psm 3]
     RFCOMM(s): UA: cr 0 dlci 0 pf 1 ilen 0 fcs 0xb6
2009-09-21 17:22:38.783554 > ACL data: handle 1 flags 0x02 dlen 12
   L2CAP(s): Disconn req: dcid 0x0040 scid 0x0041

Avoid calling rfcomm_session_put() twice by skipping this call
in rfcomm_recv_ua() if the socket is closed.
Signed-off-by: NNick Pelly <npelly@google.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

With the commit 9e726b17 the
rfcomm_session_put() gets accidentially called from a timeout
callback and results in this:

BUG: sleeping function called from invalid context at net/core/sock.c:1897
in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper
Pid: 0, comm: swapper Tainted: P           2.6.32 #31
Call Trace:
 <IRQ>  [<ffffffff81036455>] __might_sleep+0xf8/0xfa
 [<ffffffff8138ef1d>] lock_sock_nested+0x29/0xc4
 [<ffffffffa03921b3>] lock_sock+0xb/0xd [l2cap]
 [<ffffffffa03948e6>] l2cap_sock_shutdown+0x1c/0x76 [l2cap]
 [<ffffffff8106adea>] ? clockevents_program_event+0x75/0x7e
 [<ffffffff8106bea2>] ? tick_dev_program_event+0x37/0xa5
 [<ffffffffa0394967>] l2cap_sock_release+0x27/0x67 [l2cap]
 [<ffffffff8138c971>] sock_release+0x1a/0x67
 [<ffffffffa03d2492>] rfcomm_session_del+0x34/0x53 [rfcomm]
 [<ffffffffa03d24c5>] rfcomm_session_put+0x14/0x16 [rfcomm]
 [<ffffffffa03d28b4>] rfcomm_session_timeout+0xe/0x1a [rfcomm]
 [<ffffffff810554a8>] run_timer_softirq+0x1e2/0x29a
 [<ffffffffa03d28a6>] ? rfcomm_session_timeout+0x0/0x1a [rfcomm]
 [<ffffffff8104e0f6>] __do_softirq+0xfe/0x1c5
 [<ffffffff8100e8ce>] ? timer_interrupt+0x1a/0x21
 [<ffffffff8100cc4c>] call_softirq+0x1c/0x28
 [<ffffffff8100e05b>] do_softirq+0x33/0x6b
 [<ffffffff8104daf6>] irq_exit+0x36/0x85
 [<ffffffff8100d7a9>] do_IRQ+0xa6/0xbd
 [<ffffffff8100c493>] ret_from_intr+0x0/0xa
 <EOI>  [<ffffffff812585b3>] ? acpi_idle_enter_bm+0x269/0x294
 [<ffffffff812585a9>] ? acpi_idle_enter_bm+0x25f/0x294
 [<ffffffff81373ddc>] ? cpuidle_idle_call+0x97/0x107
 [<ffffffff8100aca0>] ? cpu_idle+0x53/0xaa
 [<ffffffff81429006>] ? rest_init+0x7a/0x7c
 [<ffffffff8177bc8c>] ? start_kernel+0x389/0x394
 [<ffffffff8177b29c>] ? x86_64_start_reservations+0xac/0xb0
 [<ffffffff8177b384>] ? x86_64_start_kernel+0xe4/0xeb

To fix this, the rfcomm_session_put() needs to be moved out of
rfcomm_session_timeout() into rfcomm_process_sessions(). In that
context it is perfectly fine to sleep and disconnect the socket.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Tested-by: NDavid John <davidjon@xenontk.org>

By default the RFCOMM layer would still use L2CAP basic mode. For testing
purposes this option enables RFCOMM to select enhanced retransmission
mode.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When using DEFER_SETUP on a RFCOMM socket, a SABM frame triggers
authorization which when rejected send a DM response. This is fine
according to the RFCOMM spec:

    the responding implementation may replace the "proper" response
    on the Multiplexer Control channel with a DM frame, sent on the
    referenced DLCI to indicate that the DLCI is not open, and that
    the responder would not grant a request to open it later either.

But some stacks doesn't seems to cope with this leaving DLCI 0 open after
receiving DM frame.

To fix it properly a timer was introduced to rfcomm_session which is used
to set a timeout when the last active DLC of a session is unlinked, this
will give the remote stack some time to reply with a proper DISC frame on
DLCI 0 avoiding both sides sending DISC to each other on stacks that
follow the specification and taking care of those who don't by taking
down DLCI 0.
Signed-off-by: NLuiz Augusto von Dentz <luiz.dentz@openbossa.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The rfcomm_init bug fix went into the kernel premature before it got fully
reviewed and acknowledged by the Bluetooth maintainer. So fix up the coding
style now.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

rfcomm tty may be used before rfcomm_tty_driver initilized,
The problem is that now socket layer init before tty layer, if userspace
program do socket callback right here then oops will happen.

reporting in:
http://marc.info/?l=linux-bluetooth&m=124404919324542&w=2

make 3 changes:
1. remove #ifdef in rfcomm/core.c,
make it blank function when rfcomm tty not selected in rfcomm.h

2. tune the rfcomm_init error patch to ensure
tty driver initilized before rfcomm socket usage.

3. remove __exit for rfcomm_cleanup_sockets
because above change need call it in a __init function.
Reported-by: NOliver Hartkopp <oliver@hartkopp.net>
Tested-by: NOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The Bluetooth source uses some endian conversion helpers, that in the end
translate to kernel standard routines. So remove this obfuscation since it
is fully pointless.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

There is a missing call to rfcomm_dlc_clear_timer in the case that
DEFER_SETUP is used and so the connection gets disconnected after the
timeout even if it was successfully accepted previously.

This patch adds a call to rfcomm_dlc_clear_timer to rfcomm_dlc_accept
which will get called when the user accepts the connection by calling
read() on the socket.
Signed-off-by: NJohan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The CID value of L2CAP sockets need to be set to zero. All userspace
applications do this via memset() on the sockaddr_l2 structure. The
RFCOMM implementation uses in-kernel L2CAP sockets and so it has to
make sure that l2_cid is set to zero.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When BT_DEFER_SETUP is enabled on a RFCOMM socket, then switch its
current state from BT_OPEN to BT_CONNECT2. This gives the Bluetooth
core a unified way to handle L2CAP and RFCOMM sockets. The BT_CONNECT2
state is designated for incoming connections.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When receiving incoming connection to specific services, always use
general bonding. This ensures that the link key gets stored and can be
used for further authentications.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

During a role change with pre-Bluetooth 2.1 devices, the remote side drops
the encryption of the RFCOMM connection. We allow a grace period for the
encryption to be re-established, before dropping the connection. During
this grace period, the RFCOMM_SEC_PENDING flag is set. Check this flag
before sending RFCOMM packets.
Signed-off-by: NJaikumar Ganesh <jaikumar@google.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

With the support for the enhanced security model and the support for
deferring connection setup, it is a good idea to increase various
version numbers.

This is purely cosmetic and has no effect on the behavior, but can
be really helpful when debugging problems in different kernel versions.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

A role switch with devices following the Bluetooth pre-2.1 standards
or without Encryption Pause and Resume support is not possible if
encryption is enabled. Most newer headsets require the role switch,
but also require that the connection is encrypted.

For connections with a high security mode setting, the link will be
immediately dropped. When the connection uses medium security mode
setting, then a grace period is introduced where the TX is halted and
the remote device gets a change to re-enable encryption after the
role switch. If not re-enabled the link will be dropped.

Based on initial work by Ville Tervo <ville.tervo@nokia.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Change the RFCOMM internals to use the new security levels and remove
the link mode details.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The current security model is based around the flags AUTH, ENCRYPT and
SECURE. Starting with support for the Bluetooth 2.1 specification this is
no longer sufficient. The different security levels are now defined as
SDP, LOW, MEDIUM and SECURE.

Previously it was possible to set each security independently, but this
actually doesn't make a lot of sense. For Bluetooth the encryption depends
on a previous successful authentication. Also you can only update your
existing link key if you successfully created at least one before. And of
course the update of link keys without having proper encryption in place
is a security issue.

The new security levels from the Bluetooth 2.1 specification are now
used internally. All old settings are mapped to the new values and this
way it ensures that old applications still work. The only limitation
is that it is no longer possible to set authentication without also
enabling encryption. No application should have done this anyway since
this is actually a security issue. Without encryption the integrity of
the authentication can't be guaranteed.

As default for a new L2CAP or RFCOMM connection, the LOW security level
is used. The only exception here are the service discovery sessions on
PSM 1 where SDP level is used. To have similar security strength as with
a Bluetooth 2.0 and before combination key, the MEDIUM level should be
used. This is according to the Bluetooth specification. The MEDIUM level
will not require any kind of man-in-the-middle (MITM) protection. Only
the HIGH security level will require this.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

In order to decide if listening RFCOMM sockets should be accept()ed
the BD_ADDR of the remote device needs to be known. This patch adds
a socket option which defines a timeout for deferring the actual
connection setup.

The connection setup is done after reading from the socket for the
first time. Until then writing to the socket returns ENOTCONN.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The kernel_accept() does not hold the module refcount of newsock->ops->owner,
so we need __module_get(newsock->ops->owner) code after call kernel_accept()
by hand.
In sunrpc, the module refcount is missing to hold. So this cause kernel panic.

Used following script to reproduct:

while [ 1 ];
do
    mount -t nfs4 192.168.0.19:/ /mnt
    touch /mnt/file
    umount /mnt
    lsmod | grep ipv6
done

This patch fixed the problem by add __module_get(newsock->ops->owner) to
kernel_accept(). So we do not need to used __module_get(newsock->ops->owner)
in every place when used kernel_accept().
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the introduction of CONFIG_DYNAMIC_PRINTK_DEBUG it is possible to
allow debugging without having to recompile the kernel. This patch turns
all BT_DBG() calls into pr_debug() to support dynamic debug messages.

As a side effect all CONFIG_BT_*_DEBUG statements are now removed and
some broken debug entries have been fixed.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The Bluetooth entries for the MAINTAINERS file are a little bit too
much. Consolidate them into two entries. One for Bluetooth drivers and
another one for the Bluetooth subsystem.

Also the MODULE_AUTHOR should indicate the current maintainer of the
module and actually not the original author. Fix all Bluetooth modules
to provide current maintainer information.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When an incoming RFCOMM socket connection gets converted into a TTY,
it can happen that packets are lost. This mainly happens with the
Handsfree profile where the remote side starts sending data right
away. The problem is that these packets are in the socket receive
queue. So when creating the TTY make sure to copy all pending packets
from the socket receive queue to a private queue inside the TTY.

To make this actually work, the flow control on the newly created TTY
will be disabled and only enabled again when the TTY is opened by an
application. And right before that, the pending packets will be put
into the TTY flip buffer.
Signed-off-by: NDenis Kenzior <denis.kenzior@trolltech.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When switching a RFCOMM socket to a TTY, the remote modem status might
be needed later. Currently it is lost since the original configuration
is done via the socket interface. So store the modem status and reply
it when the socket has been converted to a TTY.
Signed-off-by: NDenis Kenzior <denis.kenzior@trolltech.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

With the Simple Pairing support, the authentication requirements are
an explicit setting during the bonding process. Track and enforce the
requirements and allow higher layers like L2CAP and RFCOMM to increase
them if needed.

This patch introduces a new IOCTL that allows to query the current
authentication requirements. It is also possible to detect Simple
Pairing support in the kernel this way.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The Bluetooth specification allows to enable or disable the encryption
of an ACL link at any time by either the peer or the remote device. If
a L2CAP or RFCOMM connection requested an encrypted link, they will now
disconnect that link if the encryption gets disabled. Higher protocols
that don't care about encryption (like SDP) are not affected.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Recent tests with various Bluetooth headsets have shown that some of
them don't enforce authentication and encryption when connecting. All
of them leave it up to the host stack to enforce it. Non of them should
allow unencrypted connections, but that is how it is. So in case the
link mode settings require authentication and/or encryption it will now
also be enforced on outgoing RFCOMM connections. Previously this was
only done for incoming connections.

This support has a small drawback from a protocol level point of view
since the host stack can't really tell with 100% certainty if a remote
side is already authenticated or not. So if both sides are configured
to enforce authentication it will be requested twice. Most Bluetooth
chips are caching this information and thus no extra authentication
procedure has to be triggered over-the-air, but it can happen.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch removes CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in net/bluetooth/rfcomm/sock.c, rfcomm_sk_state_change() does the
following operation:

        if (parent && sock_flag(sk, SOCK_ZAPPED)) {
                /* We have to drop DLC lock here, otherwise
                 * rfcomm_sock_destruct() will dead lock. */
                rfcomm_dlc_unlock(d);
                rfcomm_sock_kill(sk);
                rfcomm_dlc_lock(d);
        }
}

which is fine, since rfcomm_sock_kill() will call sk_free() which will call
rfcomm_sock_destruct() which takes the rfcomm_dlc_lock()... so far so good.

HOWEVER, this assumes that the rfcomm_sk_state_change() function always gets
called with the rfcomm_dlc_lock() taken. This is the case for all but one
case, and in that case where we don't have the lock, we do a double unlock
followed by an attempt to take the lock, which due to underflow isn't
going anywhere fast.

This patch fixes this by moving the stragling case inside the lock, like
the other usages of the same call are doing in this code.

This was found with the help of the www.kerneloops.org project, where this
deadlock was observed 51 times at this point in time:
http://www.kerneloops.org/search.php?search=rfcomm_sock_destructSigned-off-by: NArjan van de Ven <arjan@linux.intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Lockdep warning will be trigged while rfcomm connection closing.

The locks taken in rfcomm_dev_add:
rfcomm_dev_lock --> d->lock

In __rfcomm_dlc_close:
d->lock --> rfcomm_dev_lock (in rfcomm_dev_state_change)

There's two way to fix it, one is in rfcomm_dev_add we first locking
d->lock then the rfcomm_dev_lock

The other (in this patch), remove the locking of d->lock for
rfcomm_dev_state_change because just locking "d->state = BT_CLOSED;"
is enough.

[  295.002046] =======================================================
[  295.002046] [ INFO: possible circular locking dependency detected ]
[  295.002046] 2.6.25-rc7 #1
[  295.002046] -------------------------------------------------------
[  295.002046] krfcommd/2705 is trying to acquire lock:
[  295.002046]  (rfcomm_dev_lock){-.--}, at: [<f89a090a>] rfcomm_dev_state_change+0x6a/0xd0 [rfcomm]
[  295.002046] 
[  295.002046] but task is already holding lock:
[  295.002046]  (&d->lock){--..}, at: [<f899c533>] __rfcomm_dlc_close+0x43/0xd0 [rfcomm]
[  295.002046] 
[  295.002046] which lock already depends on the new lock.
[  295.002046] 
[  295.002046] 
[  295.002046] the existing dependency chain (in reverse order) is:
[  295.002046] 
[  295.002046] -> #1 (&d->lock){--..}:
[  295.002046]        [<c0149b23>] check_prev_add+0xd3/0x200
[  295.002046]        [<c0149ce5>] check_prevs_add+0x95/0xe0
[  295.002046]        [<c0149f6f>] validate_chain+0x23f/0x320
[  295.002046]        [<c014b7b1>] __lock_acquire+0x1c1/0x760
[  295.002046]        [<c014c349>] lock_acquire+0x79/0xb0
[  295.002046]        [<c03d6b99>] _spin_lock+0x39/0x80
[  295.002046]        [<f89a01c0>] rfcomm_dev_add+0x240/0x360 [rfcomm]
[  295.002046]        [<f89a047e>] rfcomm_create_dev+0x6e/0xe0 [rfcomm]
[  295.002046]        [<f89a0823>] rfcomm_dev_ioctl+0x33/0x60 [rfcomm]
[  295.002046]        [<f899facc>] rfcomm_sock_ioctl+0x2c/0x50 [rfcomm]
[  295.002046]        [<c0363d38>] sock_ioctl+0x118/0x240
[  295.002046]        [<c0194196>] vfs_ioctl+0x76/0x90
[  295.002046]        [<c0194446>] do_vfs_ioctl+0x56/0x140
[  295.002046]        [<c0194569>] sys_ioctl+0x39/0x60
[  295.002046]        [<c0104faa>] syscall_call+0x7/0xb
[  295.002046]        [<ffffffff>] 0xffffffff
[  295.002046] 
[  295.002046] -> #0 (rfcomm_dev_lock){-.--}:
[  295.002046]        [<c0149a84>] check_prev_add+0x34/0x200
[  295.002046]        [<c0149ce5>] check_prevs_add+0x95/0xe0
[  295.002046]        [<c0149f6f>] validate_chain+0x23f/0x320
[  295.002046]        [<c014b7b1>] __lock_acquire+0x1c1/0x760
[  295.002046]        [<c014c349>] lock_acquire+0x79/0xb0
[  295.002046]        [<c03d6639>] _read_lock+0x39/0x80
[  295.002046]        [<f89a090a>] rfcomm_dev_state_change+0x6a/0xd0 [rfcomm]
[  295.002046]        [<f899c548>] __rfcomm_dlc_close+0x58/0xd0 [rfcomm]
[  295.002046]        [<f899d44f>] rfcomm_recv_ua+0x6f/0x120 [rfcomm]
[  295.002046]        [<f899e061>] rfcomm_recv_frame+0x171/0x1e0 [rfcomm]
[  295.002046]        [<f899e357>] rfcomm_run+0xe7/0x550 [rfcomm]
[  295.002046]        [<c013c18c>] kthread+0x5c/0xa0
[  295.002046]        [<c0105c07>] kernel_thread_helper+0x7/0x10
[  295.002046]        [<ffffffff>] 0xffffffff
[  295.002046] 
[  295.002046] other info that might help us debug this:
[  295.002046] 
[  295.002046] 2 locks held by krfcommd/2705:
[  295.002046]  #0:  (rfcomm_mutex){--..}, at: [<f899e2eb>] rfcomm_run+0x7b/0x550 [rfcomm]
[  295.002046]  #1:  (&d->lock){--..}, at: [<f899c533>] __rfcomm_dlc_close+0x43/0xd0 [rfcomm]
[  295.002046] 
[  295.002046] stack backtrace:
[  295.002046] Pid: 2705, comm: krfcommd Not tainted 2.6.25-rc7 #1
[  295.002046]  [<c0128a38>] ? printk+0x18/0x20
[  295.002046]  [<c014927f>] print_circular_bug_tail+0x6f/0x80
[  295.002046]  [<c0149a84>] check_prev_add+0x34/0x200
[  295.002046]  [<c0149ce5>] check_prevs_add+0x95/0xe0
[  295.002046]  [<c0149f6f>] validate_chain+0x23f/0x320
[  295.002046]  [<c014b7b1>] __lock_acquire+0x1c1/0x760
[  295.002046]  [<c014c349>] lock_acquire+0x79/0xb0
[  295.002046]  [<f89a090a>] ? rfcomm_dev_state_change+0x6a/0xd0 [rfcomm]
[  295.002046]  [<c03d6639>] _read_lock+0x39/0x80
[  295.002046]  [<f89a090a>] ? rfcomm_dev_state_change+0x6a/0xd0 [rfcomm]
[  295.002046]  [<f89a090a>] rfcomm_dev_state_change+0x6a/0xd0 [rfcomm]
[  295.002046]  [<f899c548>] __rfcomm_dlc_close+0x58/0xd0 [rfcomm]
[  295.002046]  [<f899d44f>] rfcomm_recv_ua+0x6f/0x120 [rfcomm]
[  295.002046]  [<f899e061>] rfcomm_recv_frame+0x171/0x1e0 [rfcomm]
[  295.002046]  [<c014abd9>] ? trace_hardirqs_on+0xb9/0x130
[  295.002046]  [<c03d6e89>] ? _spin_unlock_irqrestore+0x39/0x70
[  295.002046]  [<f899e357>] rfcomm_run+0xe7/0x550 [rfcomm]
[  295.002046]  [<c03d4559>] ? __sched_text_start+0x229/0x4c0
[  295.002046]  [<c0120000>] ? cpu_avg_load_per_task+0x20/0x30
[  295.002046]  [<f899e270>] ? rfcomm_run+0x0/0x550 [rfcomm]
[  295.002046]  [<c013c18c>] kthread+0x5c/0xa0
[  295.002046]  [<c013c130>] ? kthread+0x0/0xa0
[  295.002046]  [<c0105c07>] kernel_thread_helper+0x7/0x10
[  295.002046]  =======================
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fastcall always expands to empty, remove it.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Many-many code in the kernel initialized the timer->function
and  timer->data together with calling init_timer(timer). There
is already a helper for this. Use it for networking code.

The patch is HUGE, but makes the code 130 lines shorter
(98 insertions(+), 228 deletions(-)).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch does the full kthread conversion for the RFCOMM protocol. It
makes the code slightly simpler and more maintainable.

Based on a patch from Christoph Hellwig <hch@lst.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NNigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The RFCOMM specification says that the device closing the last DLC on
a particular session is responsible for closing the multiplexer by
closing the corresponding L2CAP channel.
Signed-off-by: NVille Tervo <ville.tervo@nokia.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The kernel provides a new convenient way to access the sockets API for
in-kernel users. It is a good idea to actually use it.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Set TASK_INTERRUPTIBLE prior to testing the flag to avoid missed wakeups.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)

Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some return values of the driver core register and create functions
are not handled and so might cause unexpected problems.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>