Implement new functionality for scheduled scan offload.  With this feature we
can scan automatically at certain intervals.

The idea is that the hardware can perform scan automatically and filter on
desired results without waking up the host unnecessarily.

Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
commands to the nl80211 interface.  When results are available they are
reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
informed when the scheduled scan has stopped with a
NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This is based on (but now quite far from) the
original work from Luis and Eliad. Add support
for configuring WoWLAN triggers, and getting
the configuration out again. Changes from the
original patchset are too numerous to list,
but one important change needs highlighting:
the suspend() callback is passed NULL for the
trigger configuration if userspace has not
configured WoWLAN at all.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Currently mac80211 uses ieee80211_disable_40mhz_24ghz module
parameter to allow disabling 40MHz operation in the 2.4GHz band.
Move this handling from mac80211 to cfg80211 so that the feature
will be more generic.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Currently cfg80211 only configures the PSM state to the driver upon creation
of a new virtual interface, but not after interface type change. The mac80211
on the other hand reinitializes its sdata structure every time the interface
type is changed, losing the PSM configuration.

Hence, if the interface type is changed to, say, ad-hoc and then back to
managed, "iw wlan0 get power_save" will claim that PSM is enabled, when in
fact on mac80211 level it is not.

Fix this in cfg80211 by configuring the PSM state to the driver each time
the interface is brought up instead of just when the interface is created.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Userspace will now be allowed to toggle between the default path
selection algorithm (HWMP, implemented in the kernel), and a vendor
specific alternative.  Also in the same patch, allow userspace to add
information elements to mesh beacons.  This is accordance with the
Extensible Path Selection Framework specified in version 7.0 of the
802.11s draft.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Instead of tying mesh activity to interface up,
add join and leave commands for mesh. Since we
must be backward compatible, let cfg80211 handle
joining a mesh if a mesh ID was pre-configured
when the device goes up.

Note that this therefore must modify mac80211 as
well since mac80211 needs to lose the logic to
start the mesh on interface up.

We now allow querying mesh parameters before the
mesh is connected, which simply returns defaults.
Setting them (internally renamed to "update") is
only allowed while connected. Specify them with
the new mesh join command instead where needed.

In mac80211, beaconing must now also follow the
mesh enabled/not enabled state, which is done
by testing the mesh ID.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

No change in output for pr_<level> prefixes.
netdev_<level> output is different, arguably improved.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This reverts commit 5a254ffe.

The commit failed to take into account that allocated wireless devices
(wiphys) are not added into the device list upon allocation, but only
when they are registered. Therefore, it opened up a race between
allocating and registering a name, so that if two processes allocate and
register concurrently ("alloc, alloc, register, register" rather than
"alloc, register, alloc, register") the code will attempt to use the
same name twice.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Choose first available phyX name when creating phy devices.  This
means that reloading a wifi driver will not cause a change in the
name of it's phy device.

Also, allow users to rename a phy to any un-used name, including
phy%d.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This adds P2P-STA and P2P-GO as device types so
we can distinguish between those and normal STA
or AP (respectively) type interfaces.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

The output becomes:

[   41.261941] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Otherwise lockdep complains...

https://bugzilla.kernel.org/show_bug.cgi?id=17311



[ INFO: possible circular locking dependency detected ]
2.6.36-rc2-git4 #12
-------------------------------------------------------
kworker/0:3/3630 is trying to acquire lock:
 (rtnl_mutex){+.+.+.}, at: [<ffffffff813396c7>] rtnl_lock+0x12/0x14

but task is already holding lock:
 (rfkill_global_mutex){+.+.+.}, at: [<ffffffffa014b129>]
rfkill_switch_all+0x24/0x49 [rfkill]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (rfkill_global_mutex){+.+.+.}:
       [<ffffffff81079ad7>] lock_acquire+0x120/0x15b
       [<ffffffff813ae869>] __mutex_lock_common+0x54/0x52e
       [<ffffffff813aede9>] mutex_lock_nested+0x34/0x39
       [<ffffffffa014b4ab>] rfkill_register+0x2b/0x29c [rfkill]
       [<ffffffffa0185ba0>] wiphy_register+0x1ae/0x270 [cfg80211]
       [<ffffffffa0206f01>] ieee80211_register_hw+0x1b4/0x3cf [mac80211]
       [<ffffffffa0292e98>] iwl_ucode_callback+0x9e9/0xae3 [iwlagn]
       [<ffffffff812d3e9d>] request_firmware_work_func+0x54/0x6f
       [<ffffffff81065d15>] kthread+0x8c/0x94
       [<ffffffff8100ac24>] kernel_thread_helper+0x4/0x10

-> #1 (cfg80211_mutex){+.+.+.}:
       [<ffffffff81079ad7>] lock_acquire+0x120/0x15b
       [<ffffffff813ae869>] __mutex_lock_common+0x54/0x52e
       [<ffffffff813aede9>] mutex_lock_nested+0x34/0x39
       [<ffffffffa018605e>] cfg80211_get_dev_from_ifindex+0x1b/0x7c [cfg80211]
       [<ffffffffa0189f36>] cfg80211_wext_giwscan+0x58/0x990 [cfg80211]
       [<ffffffff8139a3ce>] ioctl_standard_iw_point+0x1a8/0x272
       [<ffffffff8139a529>] ioctl_standard_call+0x91/0xa7
       [<ffffffff8139a687>] T.723+0xbd/0x12c
       [<ffffffff8139a727>] wext_handle_ioctl+0x31/0x6d
       [<ffffffff8133014e>] dev_ioctl+0x63d/0x67a
       [<ffffffff8131afd9>] sock_ioctl+0x48/0x21d
       [<ffffffff81102abd>] do_vfs_ioctl+0x4ba/0x509
       [<ffffffff81102b5d>] sys_ioctl+0x51/0x74
       [<ffffffff81009e02>] system_call_fastpath+0x16/0x1b

-> #0 (rtnl_mutex){+.+.+.}:
       [<ffffffff810796b0>] __lock_acquire+0xa93/0xd9a
       [<ffffffff81079ad7>] lock_acquire+0x120/0x15b
       [<ffffffff813ae869>] __mutex_lock_common+0x54/0x52e
       [<ffffffff813aede9>] mutex_lock_nested+0x34/0x39
       [<ffffffff813396c7>] rtnl_lock+0x12/0x14
       [<ffffffffa0185cb5>] cfg80211_rfkill_set_block+0x1a/0x7b [cfg80211]
       [<ffffffffa014aed0>] rfkill_set_block+0x80/0xd5 [rfkill]
       [<ffffffffa014b07e>] __rfkill_switch_all+0x3f/0x6f [rfkill]
       [<ffffffffa014b13d>] rfkill_switch_all+0x38/0x49 [rfkill]
       [<ffffffffa014b821>] rfkill_op_handler+0x105/0x136 [rfkill]
       [<ffffffff81060708>] process_one_work+0x248/0x403
       [<ffffffff81062620>] worker_thread+0x139/0x214
       [<ffffffff81065d15>] kthread+0x8c/0x94
       [<ffffffff8100ac24>] kernel_thread_helper+0x4/0x10

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>

Allow userspace to register for more than just
action frames by giving the frame subtype, and
make it possible to use this in various modes
as well.

With some tweaks and some added functionality
this will, in the future, also be usable in AP
mode and be able to replace the cooked monitor
interface currently used in that case.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Enable using network namespaces with
wireless devices even when sysfs is
enabled using the same infrastructure
that was built for netdevs.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Save a few bytes of text

(allyesconfig)
$ size drivers/net/wireless/built-in.o*
   text	   data	    bss	    dec	    hex	filename
3924568	 100548	 871056	4896172	 4ab5ac	drivers/net/wireless/built-in.o.new
3926520	 100548	 871464	4898532	 4abee4	drivers/net/wireless/built-in.o.old

$ size net/wireless/core.o*
   text	   data	    bss	    dec	    hex	filename
  12843	    216	   3768	  16827	   41bb	net/wireless/core.o.new
  12328	    216	   3656	  16200	   3f48	net/wireless/core.o

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

device_add() is called before adding the phy to the cfg80211 device
list.

So if a userspace program uses sysfs uevents to detect new phy
devices, and queries nl80211 to get phy info, it can get ENODEV even
though the phy exists in sysfs.

An easy workaround is to hold the cfg80211 mutex until the phy is
present in sysfs/cfg80211/debugfs.

Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

cfg80211_exit is only used as module_exit function, so it can go to
.exit.text saving a few bytes when CONFIG_CFG80211=y.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Now that the mac80211 is choosing dynamic ps timeouts based on the ps-qos
network latency configuration, configure a default value of -1 as the dynamic
ps timeout in cfg80211. This value allows the mac80211 to determine the value
to be used.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py



The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

The most needed command from nl80211, which Wireless Extensions had,
is support for power save mode. Add a simple command to make it possible
to enable and disable power save via nl80211.

I was also planning about extending the interface, for example adding the
timeout value, but after thinking more about this I decided not to do it.
Basically there were three reasons:

Firstly, the parameters for power save are very much hardware dependent.
Trying to find a unified interface which would work with all hardware, and
still make sense to users, will be very difficult.

Secondly, IEEE 802.11 power save implementation in Linux is still in state
of flux. We have a long way to still to go and there is no way to predict
what kind of implementation we will have after few years. And because we
need to support nl80211 interface a long time, practically forever, adding
now parameters to nl80211 might create maintenance problems later on.

Third issue are the users. Power save parameters are mostly used for
debugging, so debugfs is better, more flexible, interface for this.
For example, wpa_supplicant currently doesn't configure anything related
to power save mode. It's better to strive that kernel can automatically
optimise the power save parameters, like with help of pm qos network
and other traffic parameters.

Later on, when we have better understanding of power save, we can extend
this command with more features, if there's a need for that.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This implements a new command to register for action frames
that userspace wants to handle instead of the in-kernel
rejection. It is then responsible for rejecting ones that
it decided not to handle. There is no unregistration, but
the socket can be closed for that.

Frames that are not registered for will not be forwarded
to userspace and will be rejected by the kernel, the
cfg80211 API helps implementing that.

Additionally, this patch adds a new command that allows
doing action frame transmission from userspace. It can be
used either to exchange action frames on the current
operational channel (e.g., with the AP with which we are
currently associated) or to exchange off-channel Public
Action frames with the remain-on-channel command.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

If a device has multiple MAC addresses, userspace will
need to know about that. Similarly, if it allows the
MAC addresses to vary by a bitmask.

If a driver exports multiple addresses, it is assumed
that it will be able to deal with that many different
addresses, which need not necessarily match the ones
programmed into the device; if a mask is set then the
device should deal addresses within that mask based
on an arbitrary "base address".

To test it all and show how it is used, add support
to hwsim even though it can't actually deal with
addresses different from the default.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Future code will need to look up rdev and wdev
within atomic sections, but currently we need
to lock a mutex for such lookups. Change the
list handling for both to be RCU-safe so that
we can look them up in rcu sections instead in
the future.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

The new attribute NL80211_ATTR_WIPHY_COVERAGE_CLASS sets IEEE 802.11
Coverage Class, which depends on maximum distance of nodes in a
wireless network. It's required for long distance links (more than a few
hundred meters).

The attribute is now ignored by two non-mac80211 drivers, rndis and
iwmc3200wifi, together with WIPHY_PARAM_RETRY_SHORT and
WIPHY_PARAM_RETRY_LONG. If it turns out to be a problem, we could split
set_wiphy_params callback or add new capability bits.

Signed-off-by: Lukas Turek <8an@praha12.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

When CONFIG_CFG80211_WEXT is not set, there is
a refcount imbalance with rdev->opencount, fix
that by moving it out of the ifdef.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

This patch moves the works cleanup, scan and events to a cfg80211
dedicated workqueue.

Platform driver like eeepc-laptop ought to use works to rfkill (as
new rfkill does lock in rfkill_unregister and the platform driver is
called from rfkill_switch_all which also lock the same mutex).
This raise a new issue in itself that the work scheduled by the platform
driver to the global worqueue calls wiphy_unregister which flush_work
scan and event works (which thus flush works on the global workqueue inside
a work on the global workqueue) and also put on hold the  wdev_cleanup_work
 (which prevents the dev_put on netdev thus indefinite Usage count error on
wifi device).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Alban Browaeys <prahal@yahoo.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

A number of people have tried to add a wireless interface
(in managed mode) to a bridge and then complained that it
doesn't work. It cannot work, however, because in 802.11
networks all packets need to be acknowledged and as such
need to be sent to the right address. Promiscuous doesn't
help here. The wireless address format used for these
links has only space for three addresses, the
 * transmitter, which must be equal to the sender (origin)
 * receiver (on the wireless medium), which is the AP in
   the case of managed mode
 * the recipient (destination), which is on the APs local
   network segment

In an IBSS, it is similar, but the receiver and recipient
must match and the third address is used as the BSSID.

To avoid such mistakes in the future, disallow adding a
wireless interface to a bridge.

Felix has recently added a four-address mode to the AP
and client side that can be used (after negotiating that
it is possible, which must happen out-of-band by setting
up both sides) for bridging, so allow that case.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

We've accumulated a number of options for wiphys
which make more sense as flags as we keep adding
more. Convert the existing ones.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

We can save a lot of code and pointers in the structs
by using debugfs_remove_recursive().

First, change cfg80211 to use debugfs_remove_recursive()
so that drivers do not need to clean up any files they
added to the per-wiphy debugfs (if and only if they are
ok to be accessed until after wiphy_unregister!).

Then also make mac80211 use debugfs_remove_recursive()
where necessary -- it need not remove per-wiphy files
as cfg80211 now removes those, but netdev etc. files
still need to be handled but can now be removed without
needing struct dentry pointers to all of them.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Signed-off-by: John W. Linville <linville@tuxdriver.com>

Refactor wext to
 * split out iwpriv handling
 * split out iwspy handling
 * split out procfs support
 * allow cfg80211 to have wireless extensions compat code
   w/o CONFIG_WIRELESS_EXT

After this, drivers need to
 - select WIRELESS_EXT	- for wext support
 - select WEXT_PRIV	- for iwpriv support
 - select WEXT_SPY	- for iwspy support

except cfg80211 -- which gets new hooks in wext-core.c
and can then get wext handlers without CONFIG_WIRELESS_EXT.

Wireless extensions procfs support is auto-selected
based on PROC_FS and anything that requires the wext core
(i.e. WIRELESS_EXT or CFG80211_WEXT).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Instead of having to modify every non-mac80211 for device type assignment,
do this inside the netdev notifier callback of cfg80211. So all drivers
that integrate with cfg80211 will export a proper device type.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the interface type changes while connected, and the
driver does not require the interface to be down for a
type change, it is currently possible to get very strange
results unless the driver takes special care, which it
shouldn't have to.

To fix this, take care to disconnect/leave IBSS when
changing the interface type -- even if the driver may fail
the call. Also process all events that may be pending to
avoid running into a situation where an event is reported
but only processed after the type has already changed,
which would lead to missing events and warnings.

A side effect of this is that you will have disconnected
or left the IBSS even if the mode change ultimately fails,
but since the intention was to change it and thus leave or
disconnect, this is not a problem.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

When we lose a scan, cfg80211 tries to clean up after
the driver. However, it currently does this too early,
it does this in GOING_DOWN already instead of DOWN, so
it may happen with mac80211. Besides fixing this, also
make it more robust by leaking the scan request so if
the driver later actually finishes the scan, it won't
crash. Also check in ___cfg80211_scan_done whether a
scan request is still pending and exit if not.

Reported-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

In case of connection failure, the bssid info is not a must have.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

My patch "cfg80211: fix deadlock" broke the code it
was supposed to fix, the scan request checking. But
it's not trivial to put it back the way it was, since
the original patch had a deadlock.

Now do it in a completely new way: queue the check
off to a work struct, where we can freely lock. But
that has some more complications, like needing to
wait for it to be done before the wiphy/rdev can be
destroyed, so some code is required to handle that.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

When removing an interface with nl80211, cfg80211 will
deadlock in the netdev notifier because we're already
holding rdev->mtx and try to acquire it again to verify
the scan has been done.

This bug was introduced by my patch
"cfg80211: check for and abort dangling scan requests".

To fix this, move the dangling scan request check into
wiphy_unregister(). This will not be able to catch all
cases right away, but if the scan problem happens with
a manual ifdown or so it will be possible to remedy it
by removing the module/device.

Additionally, add comments about the deadlock scenario.

Reported-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Christian Lamparter <chunkeey@web.de>
Tested-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Sometimes drivers might have a good reason to override
the PS default, like iwlwifi right now where it affects
RX performance significantly at this point. This will
allow them to override the default, if desired, in a
way that users can still change it according to their
trade-off choices, not the driver's, like would happen
if the driver just disabled PS completely then.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

If you trigger a scan request on an interface and then
take it down, or rmmod the module or unplug the device
the driver might "forget" to cancel the scan request.
That is a bug in the driver, but the current behaviour
is that we just hang endlessly waiting for the netdev
refcount to become 0 which it never will. To improve
robustness, check for this situation in cfg80211, warn
about it and clean up behind the driver. I don't just
clean up silently because it's likely that the driver
also has some internal state it has now leaked.

Additionally, this fixes a locking bug, clearing the
scan_req pointer should be done under the rdev lock.

Finally, we also need to _wait_ for the scan work and
not just abort it since it might be pending and wanting
to do a cleanup.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>