The on-channel work optimisations have caused a
number of issues, and the code is unfortunately
very complex and almost impossible to follow.
Instead of attempting to put in more workarounds
let's just remove those optimisations, we can
work on them again later, after we change the
whole auth/assoc design.
This should fix rate_control_send_low() warnings,
see RH bug 731365.
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Attempting to micro-optimise the scan by going
fully live again when scanning the operating
channel just made the code extremely complex
and has little gain in most use cases. Remove
all that code and simplify the state machine
again.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (63 commits)
PM / Clocks: Remove redundant NULL checks before kfree()
PM / Documentation: Update docs about suspend and CPU hotplug
ACPI / PM: Add Sony VGN-FW21E to nonvs blacklist.
ARM: mach-shmobile: sh7372 A4R support (v4)
ARM: mach-shmobile: sh7372 A3SP support (v4)
PM / Sleep: Mark devices involved in wakeup signaling during suspend
PM / Hibernate: Improve performance of LZO/plain hibernation, checksum image
PM / Hibernate: Do not initialize static and extern variables to 0
PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too
PM / Hibernate: Add resumedelay kernel param in addition to resumewait
MAINTAINERS: Update linux-pm list address
PM / ACPI: Blacklist Vaio VGN-FW520F machine known to require acpi_sleep=nonvs
PM / ACPI: Blacklist Sony Vaio known to require acpi_sleep=nonvs
PM / Hibernate: Add resumewait param to support MMC-like devices as resume file
PM / Hibernate: Fix typo in a kerneldoc comment
PM / Hibernate: Freeze kernel threads after preallocating memory
PM: Update the policy on default wakeup settings
PM / VT: Cleanup #if defined uglyness and fix compile error
PM / Suspend: Off by one in pm_suspend()
PM / Hibernate: Include storage keys in hibernation image on s390
...
This is needed so that offloaded scan can do the
right thing. Without this patch, the no_cck flag
contains random values from the kernel heap.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Whenever the scan request or tx_mgmt is requesting not to
use CCK rate for managemet frames through
NL80211_ATTR_TX_NO_CCK_RATE attribute, then mac80211 should
select appropriate least non-CCK rate. This could help to
send P2P probes and P2P action frames at non 11b rates
without diabling 11b rates globally.
Cc: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The PM QoS implementation files are better named
kernel/power/qos.c and include/linux/pm_qos.h.
The PM QoS support is compiled under the CONFIG_PM option.
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Scanning currently uses the TX rate mask to
restrict the rate set, which is bogus. Make
it use the new set of rates from userspace.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We were not allocating memory for the IEs passed in the scheduled_scan
request and this was causing memory corruption (buffer overflow).
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Do not send DS Channel parameter for directed probe requests
in order to maximize the chance that we get a response. Some
badly-behaved APs don't respond when this parameter is included.
Signed-off-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Advertise only user-requested bitrates in a HW scan.
Note that the hw_scan API doesn't currently have a
way of asking for a specific probe request bitrate,
so we might end up using a bitrate that we don't
advertise as supported. I'll fix that later.
Also add a hexdump printk to hwsim to verify this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When suspending, __ieee80211_suspend() calls ieee80211_scan_cancel(),
which will only cancel sw scan. In order to cancel hw scan, the
low-level driver has to cancel it in the suspend() callback. however,
this is too late, as a new scan_work will be enqueued (while the driver
is going into suspend).
Add a new cancel_hw_scan() callback, asking the driver to cancel an
active hw scan, and call it in ieee80211_scan_cancel().
Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Commit 79f460ca49 add a duplicate
linux/slab.h include to net/mac80211/scan.c - remove it.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Acked-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
As long as no delay is required b/w channel change, scan work
is proceeding without scheduling a new work. In such case, we
can not abort scan work when the card was unplugged. This patch
completes the scanning immediately whenever the device goes down.
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When sched_scan_stopped was called by the driver, mac80211 calls
cfg80211, which in turn was calling mac80211 back with a flag
"driver_initiated". This flag was used so that mac80211 would do the
necessary cleanup but would not call the driver. This was enough to
prevent the bounce back between the driver and mac80211, but not
between mac80211 and cfg80211.
To fix this, we now do the cleanup in mac80211 before calling
cfg80211. To help with locking issues, the workqueue was moved from
cfg80211 to mac80211.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Implement support for HW scheduled scan. The mac80211 code doesn't perform
scheduled scans itself, but calls the driver to start and stop scheduled
scans.
This patch also creates a trace event class to be used by drv_hw_scan
and the new drv_sched_scan_start and drv_sched_stop functions, in
order to avoid duplicate code.
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This seems to be a leftover from the old days, when we didn't support
any frames that didn't contain the full ieee802.11 header. This is
not the case anymore. It does not cause problems now, because they
are only dropped during scan. But when scheduled scans get merged,
this would become a problem because we would drop all small frames
while scheduled scan is running.
To fix this, return RX_CONTINUE instead of RX_DROP_MONITOR.
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The scan code has a race that Michael reported
he ran into, but it's easy to fix while at the
same time simplifying the code.
The race resulted in the following warning:
------------[ cut here ]------------
WARNING: at net/mac80211/scan.c:310 ieee80211_rx_bss_free+0x20c/0x4b8 [mac80211]()
Modules linked in: [...]
[<c0033edc>] (unwind_backtrace+0x0/0xe0) from [<c004f2a4>] (warn_slowpath_common+0x4c/0x64)
[... backtrace wasn't useful ...]
Reported-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
My previous patch to optimize scanning on operating channel
accidentally removed the code that would ensure power was
set to maximum for scanning.
This patch re-adds that functionality.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Previous code set the channel type to NO_HT, but it
appears that NO_HT packets can be sent on any channel
type, so we do not need to change the channel type
as long as the channel is correct.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This should decrease un-necessary flushes, on/off channel work,
and channel changes in cases where the only scanned channel is
the current operating channel.
* Removes SCAN_OFF_CHANNEL flag, uses SDATA_STATE_OFFCHANNEL
and is-scanning flags instead.
* Add helper method to determine if we are currently configured
for the operating channel.
* Do no blindly go off/on channel in work.c Instead, only call
appropriate on/off code when we really need to change channels.
Always enable offchannel-ps mode when starting work,
and disable it when we are done.
* Consolidate ieee80211_offchannel_stop_station and
ieee80211_offchannel_stop_beaconing, call it
ieee80211_offchannel_stop_vifs instead.
* Accept non-beacon frames when scanning on operating channel.
* Scan state machine optimized to minimize on/off channel
transitions. Also, when going on-channel, go ahead and
re-enable beaconing. We're going to be there for 200ms,
so seems like some useful beaconing could happen.
Always enable offchannel-ps mode when starting software
scan, and disable it when we are done.
* Grab local->mtx earlier in __ieee80211_scan_completed_finish
so that we are protected when calling hw_config(), etc.
* Pass probe-responses up the stack if scanning on local
channel, so that mlme can take a look.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Extend channel to frequency mapping for 802.11j Japan 4.9GHz band, according to
IEEE802.11 section 17.3.8.3.2 and Annex J. Because there are now overlapping
channel numbers in the 2GHz and 5GHz band we can't map from channel to
frequency without knowing the band. This is no problem as in most contexts we
know the band. In places where we don't know the band (and WEXT compatibility)
we assume the 2GHz band for channels below 14.
This patch does not implement all channel to frequency mappings defined in
802.11, it's just an extension for 802.11j 20MHz channels. 5MHz and 10MHz
channels as well as 802.11y channels have been omitted.
The following drivers have been updated to reflect the API changes:
iwl-3945, iwl-agn, iwmc3200wifi, libertas, mwl8k, rt2x00, wl1251, wl12xx.
The drivers have been compile-tested only.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Brian Prodoehl <bprodoehl@gmail.com>
Acked-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The recent scan overhaul broke locking
because now we can jump to code that
attempts to unlock, while we don't have
the mutex held. Fix this by holding the
mutex around all the relevant code.
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
net/mac80211/scan.c: In function ‘ieee80211_scan_cancel’:
net/mac80211/scan.c:794: warning: ‘finish’ may be used uninitialized in this function
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We nulify local->scan_req on failure in __ieee80211_start_scan, so
__ieee80211_scan_completed will not call cfg80211_scan_done. Fix that.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When performing hw scan and not abort it, __ieee80211_scan_completed()
is currently called from scan work, so does not need to reschedule work
to call drv_hw_scan().
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This is partial revert and fix for commit
85f72bc839 "mac80211: only cancel
software-based scans on suspend"
When cfg80211 request the scan and mac80211 perform some management work,
we defer the scan request. We do not canceling such requests when calling
ieee80211_scan_cancel(), because of SCAN_SW_SCANNING bit check just
before the call. So fix that problem.
Another problem, which commit 85f72bc839
tries to solve, is we can not cancel HW scan. Hence patch make
ieee80211_scan_cancel() ignore HW scan (see code comments). Keeping
local->mtx lock assures that the deferred scan will not become
"working" HW scan.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We are taking local->mtx inside __ieee80211_scan_completed(), but just
before call to that function we drop the lock. Dropping/taking lock is not
good, because can lead to hard to understand race conditions.
Patch split scan_completed() code into two functions, first must be called
with local->mtx taken and second without it.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Use goto instruction to call __ieee80211_scan_completed only ones in
ieee80211_scan_work. This is prepare for the next patch.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
IEEE Std 802.11k-2008 added DS Parameter Set information element into
Probe Request frames as an optional information on 2.4 GHz band (and
mandatory, if radio measurements are enabled). This allows APs to
filter out Probe Request frames that may be received from neighboring
overlapping channels and by doing so, reduce the number of unnecessary
frames in the air. Make mac80211 add this IE into Probe Request frames
whenever the channel is known (i.e., whenever hwscan is not used).
Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If the TX rate set has been masked, the removed rates can also be
removed from the Supported Rates and Extended Supported Rates IEs in
Probe Request frames.
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The ieee80211_scan_completed() function was a frequent
source of potential deadlocks, since it is called by
drivers but may call back into drivers, so drivers had
to make sure to call it without any locks held, which
frequently lead to more complex code in drivers. Avoid
that problem by allowing the function to be called in
any context, and queueing the actual work it does.
Also update the documentation for it to indicate this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Sometimes we don't just need to know whether or
not the device is idle, but also per interface.
This adds that reporting capability to mac80211.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Having both scan and work mutexes is not just
a bit too fine grained, it also creates issues
when there's code that needs both since they
then need to be acquired in the right order,
which can be hard to do.
Therefore, use just a single mutex for both.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Releasing the scan mutex while starting scans
can lead to unexpected things happening, so
we shouldn't do that. Fix that and hold the
mutex across the scan triggering.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Some features require knowing the DTIM period
before associating. This implements the ability
to wait for a beacon in mac80211 before assoc
to provide this value. It is optional since
most likely not all drivers will need this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This reverts this commit. While in theory the change is
correct the patch does not address current assumptions made
by some drivers, one which is definitley affected is ath9k.
Prior to this change the scan complete callback would be
called after we returned to the home channel and configured
the hardware RX filters. After this change we call the scan
complete callback prior to both the hw config and the config
filter. At least for ath9k this breaks quite a few assumptions
on the callback, leading to disconnects to the AP after every scan
making the driver pretty useless on STA mode. The goal behind
this commit was to address the now understood spurious warnings
from ath9k and mac80211_hwsim on scanning on two wiphys at the
same time but we have now supressed these and will address this
issue in the next kernel release.
When fixing this for good next we must first review the other
driver's dependence on this logic and perhaps consider removal
of the scan complete callback all together.
Cc: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Fix the following compile warning:
CC [M] net/mac80211/scan.o
net/mac80211/scan.c: In function 'ieee80211_request_internal_scan':
net/mac80211/scan.c:749:23: warning: comparison between 'enum nl80211_band' and 'enum ieee80211_band'
caused by the local variable band not being of the proper 'ieee80211_band' type.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently, detection in hwsim and ath9k can
detect that two sw scans are in flight at the
same time, which isn't really true. It is
caused by a race condition, because the scan
complete callback is called too late, after
the lock has been dropped, so that a new scan
can be started before it is called.
It is also called too early semantically, as
it is currently called _after_ the return to
the operating channel -- it should be before
so that drivers know this is the operating
channel again.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1674 commits)
qlcnic: adding co maintainer
ixgbe: add support for active DA cables
ixgbe: dcb, do not tag tc_prio_control frames
ixgbe: fix ixgbe_tx_is_paused logic
ixgbe: always enable vlan strip/insert when DCB is enabled
ixgbe: remove some redundant code in setting FCoE FIP filter
ixgbe: fix wrong offset to fc_frame_header in ixgbe_fcoe_ddp
ixgbe: fix header len when unsplit packet overflows to data buffer
ipv6: Never schedule DAD timer on dead address
ipv6: Use POSTDAD state
ipv6: Use state_lock to protect ifa state
ipv6: Replace inet6_ifaddr->dead with state
cxgb4: notify upper drivers if the device is already up when they load
cxgb4: keep interrupts available when the ports are brought down
cxgb4: fix initial addition of MAC address
cnic: Return SPQ credit to bnx2x after ring setup and shutdown.
cnic: Convert cnic_local_flags to atomic ops.
can: Fix SJA1000 command register writes on SMP systems
bridge: fix build for CONFIG_SYSFS disabled
ARCNET: Limit com20020 PCI ID matches for SOHARD cards
...
Fix up various conflicts with pcmcia tree drivers/net/
{pcmcia/3c589_cs.c, wireless/orinoco/orinoco_cs.c and
wireless/orinoco/spectrum_cs.c} and feature removal
(Documentation/feature-removal-schedule.txt).
Also fix a non-content conflict due to pm_qos_requirement getting
renamed in the PM tree (now pm_qos_request) in net/mac80211/scan.c
When IBSS is fixed to a frequency, it can still
scan to try to find the right BSSID. This makes
sense if the BSSID isn't also fixed, but it need
not scan all channels -- just one is sufficient.
Make it do that by moving the scan setup code to
ieee80211_request_internal_scan() and include
a channel variable setting.
Note that this can be further improved to start
the IBSS right away if both frequency and BSSID
are fixed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Use old supported rates, if AP do not provide supported rates
information element in a new managment frame.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When scanning, it is somewhat important to scan
on the correct virtual interface. All drivers
that currently implement hw_scan only support a
single virtual interface, but that may change
and then we'd want to be ready.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Enhance tracing by adding tracing for a variety of
callbacks that the drivers call, and also for
internal calls (currently limited to queue status).
This can aid debugging what is going on in mac80211
in interaction with drivers, since we can now see
what drivers call and not just what mac80211 calls
in the driver.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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>
