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286,663 commits

Author SHA1 Message Date
Jussi Kivilinna
a7cf534d4d rndis_wlan: remove unused macro
NET_TYPE_11FB actually has never been used.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:09 -05:00
Jussi Kivilinna
1c70687536 rndis_wlan: add reporting of PMKSA candidate events
Convert old WEXT reporting to use new cfg80211_pmksa_candidate_notify().

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:08 -05:00
Jussi Kivilinna
30fd90731d rndis_wlan: add missing __packed
Some structures were missing __packed.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:07 -05:00
Jussi Kivilinna
6f104a081b rndis_wlan: pass channel info to cfg80211_roamed()
cfg80211_roamed() now has channel parameter so add passing current channel
info.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:07 -05:00
Jussi Kivilinna
cb82a66d0f rndis_wlan: split getting current channel to separate function
Split getting current channel channel from hardware to separate function
as this function will be needed later in patch 'pass channel info to
cfg80211_roamed()'.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:06 -05:00
Ben Greear
ef96a84202 mac80211: Support ht-cap over-rides.
This implements ht-cap over-rides for mac80211 drivers.
HT may be disabled, making an /a/b/g/n station act like an
a/b/g station.  HT40 may be disabled forcing the station to
be HT20 even if the AP and local hardware support HT40.

MAX-AMSDU may be disabled.
AMPDU-Density may be increased.
AMPDU-Factor may be decreased.

This has been successfully tested with ath9k using patched
wpa_supplicant and iw.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:06 -05:00
Ben Greear
7e7c8926b2 wireless: Support ht-capabilities over-rides.
This allows users to disable features such as HT, HT40,
and to modify the MCS, AMPDU, and AMSDU settings for
drivers that support it.

The MCS, AMPDU, and AMSDU features that may be disabled are
are reported in the phy-info netlink message as a mask.

Attemping to disable features that are not supported will
take no affect, but will not return errors.  This is to aid
backwards compatibility in user-space apps that may not be
clever enough to deal with parsing the the capabilities mask.

This patch only enables the infrastructure.  An additional
patch will enable the feature in mac80211.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:22:06 -05:00
Johannes Berg
dd76986b0e cfg80211/mac80211: Revert "move information element parsing logic to cfg80211"
No other driver ever ended up using this, and
the commit forgot to move the prototype so no
driver could have used it. Revert it, if any
driver shows up and needs it it can be moved
again, but until then it's more efficient to
have it in mac80211 where the only user is.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:49 -05:00
Johannes Berg
80b998993d nl80211: make get_vlan logic more common
get_vlan() sets the output parameter even if it
returns an error, which is a bit odd. Instead,
convert it to use ERR_PTR.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:49 -05:00
Johannes Berg
7c4ef7122c cfg80211: add flags for off-channel capabilities
Currently mac80211 implements these for all devices,
but given restrictions of some devices that isn't
really true, so prepare for being able to remove the
capability for some mac80211 devices.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:49 -05:00
Johannes Berg
f2dc7989bf mac80211: minor cleanup to mesh state locking
First time I tried smatch, and it says:
mesh_hwmp.c +870 mesh_queue_preq(21) error: double lock 'bottom_half:'
mesh_hwmp.c +873 mesh_queue_preq(24) error: double unlock 'bottom_half:'
mesh_hwmp.c +886 mesh_queue_preq(37) error: double unlock 'bottom_half:'

Which is indeed true -- there's no point in disabling BHs
again if we just did that a few lines earlier, so remove.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:48 -05:00
Joe Perches
1e7aecc26b iwl-debug: Shrink object by using dev_err and deduplicating formats
Using dev_err instead of dev_printk(KERN_ERR uses fewer
arguments and is a bit smaller.

Deduplicating formats used by IWL_DEBUG_QUIET_RFKILL also
makes the object a bit smaller.

Neatened the macros, used ##__VA_ARGS__.

$ size drivers/net/wireless/iwlwifi/built-in.o*
   text	   data	    bss	    dec	    hex	filename
 462652	   8646	  92576	 563874	  89aa2	drivers/net/wireless/iwlwifi/built-in.o.new
 467557	   8646	  92592	 568795	  8addb	drivers/net/wireless/iwlwifi/built-in.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:48 -05:00
Wey-Yi Guy
1ffeb2a3e9 iwlwifi: remove redundancy
just use iwl_bus, remove the redundancy

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:48 -05:00
Emmanuel Grumbach
b3f15ef22c iwlwifi: tid_data is taken twice in iwl_trans_pcie_tx_agg_alloc
Remove this redundancy.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:48 -05:00
Emmanuel Grumbach
4bf218c033 iwlwifi: fix endianity issues in debug prints
Use the CPUed version of the variables when printing data from the
BA notification.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:47 -05:00
Emmanuel Grumbach
1daf04b8ac iwlwifi: improve the prints in the reclaim path
Some information was redundation, other was missing.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:47 -05:00
Emmanuel Grumbach
08d1700da0 iwlwifi: check the HW when a queue is stuck
Add more information when a queue is stuck and actually get
information from the scheduler instead of looking at internal
variables.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:47 -05:00
Thomas Meyer
1f1d528977 brcm80211: smac: Use kmemdup rather than duplicating its implementation
The semantic patch that makes this change is available
in scripts/coccinelle/api/memdup.cocci.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Acked-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:46 -05:00
Larry Finger
0dcc3c8429 rtlwifi: Remove redundant code from PCI interrupt
The interrupt routine for PCI devices has a special exit that
executes the same instructions as does the normal exit.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:46 -05:00
Larry Finger
abfabc9b48 rtlwifi: rtl8192cu: Fix endianian issues
Driver rtlwifi fails on a big-endian host.

These changes have been tested on a Mac PowerBook G4, which has
a PPC processor.

Although this patch touches some of the code that will affect endian
issues on PCI hardware through drivers rtl8192ce, rtl8192se, and
rtl8192de, these have not been tested due to lack of suitable hardware.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:46 -05:00
Larry Finger
ff6ff96b5b rtlwifi: rtl8192cu: Change firmware upload to use block writes
Driver rtl8192cu writes the firmware with 32-bit asynchronous writes. This
design is OK for USB 2.0 adapters, but the current implementation of
xhcu-hcd has a limited ring size, which is exceeded. By converting to
synchronous block writes, this error is avoided.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:45 -05:00
George
040a72785c rtlwifi: rtl8192cu: Allow retries for USB I/O
The USB driver does not retry reads - allow 10 tries.

Signed-off-by: George <george0505@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:44 -05:00
Kalle Valo
4745fc095d nl80211: add testmode to the list of supported commands
User space might want to test if driver supports testmode. Adding testmode
to the list of supported commands makes this easier.

I omitted testmode_dump() in purpose. I assume all drivers implementing
testmode_dump() will also implement testmode_cmd().

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:43 -05:00
Johannes Berg
fb4431bf60 mac80211: remove unused ASSOC_AP flag
WLAN_STA_ASSOC_AP indicates that the station entry
is for an AP we're associated to but isn't used so
remove it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:43 -05:00
Johannes Berg
11127e9121 mac80211: transmit fragment list to drivers
Drivers can usually handle fragmented packets
much easier when they get the entire list of
fragments at once. The only thing they need to
do is keep enough space on the queues for up
to ten fragments of a single MSDU.

This allows them to implement this with a new
operation tx_frags.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:43 -05:00
Johannes Berg
74e4dbfd57 mac80211: make TX LED handling independent of fragmentation
This just prepares for passing the entire fragment
list to the driver. No significant changes, but the
TX throughput is calculated slightly differently
now and we blink only once for each MSDU.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:43 -05:00
Johannes Berg
a1a3fcec6f mac80211: move fragment flag adjustment
Instead of adjusting the fragment flags at
TX time, adjust them at fragmentation time.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:42 -05:00
Johannes Berg
252b86c432 mac80211: use skb list for fragments
We are currently linking the skbs by using skb->next
directly. This works, but the preferred way is to use
a struct sk_buff_head instead. That also prepares for
passing that to drivers directly.

While at it I noticed we calculate the duration for
fragments twice -- remove one of them.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:42 -05:00
Zefir Kurtisi
83c7657096 ath9k: trivial: reorder rx_tasklet processing
DFS events are reported as PHY errors and need to be processed
with a correct timestamp set before ath9k_skb_preprocess() is
called and the frame is possibly dropped.

This patch puts the rxs->mactime calculation before the skb
is preprocessed to prepare for DFS event reporting.

Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:42 -05:00
Luis R. Rodriguez
b68e6b3b33 cfg80211: pass DFS region to drivers through reg_notifier()
This grants drivers access to the DFS region that a
regulatory domain belongs to.

Signed-off-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:41 -05:00
Luis R. Rodriguez
8b60b07805 cfg80211: process regulatory DFS region for countries
The wireless-regdb now has support for mapping a country to
one DFS region. CRDA sends this to us now so process it
so we can provide that hint to drivers. This will later be
used by code for processing DFS in a way that meets the
criteria for the DFS region the country belongs to.

Signed-off-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-11-21 16:20:41 -05:00
Eric Dumazet
9205fd9cca tg3: switch to build_skb() infrastructure
This is very similar to bnx2x conversion, but simpler since no special
alignement is required, so goal was not to reduce skb truesize.

Using build_skb() reduces cache line misses in the driver, since we
use cache hot skb instead of cold ones. Number of in-flight sk_buff
structures is lower, they are more likely recycled in SLUB caches
while still hot.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Matt Carlson <mcarlson@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
CC: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-21 16:10:31 -05:00
John W. Linville
4713e962c5 Merge branch 'for-linville' of git://github.com/sgruszka/iwlegacy 2011-11-21 16:00:56 -05:00
Tejun Heo
ec012476af usb_storage: don't use set_freezable_with_signal()
The current implementation of set_freezable_with_signal() is buggy and
tricky to get right.  usb-storage is the only user and its use can be
avoided trivially.

All usb-storage wants is to be able to sleep with timeout and get
woken up if freezing() becomes true.  This can be trivially
implemented by doing interruptible wait w/ freezing() included in the
wait condition.  There's no reason to use set_freezable_with_signal().

Perform interruptible wait on freezing() instead of using
set_freezable_with_signal(), which is scheduled for removal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-21 12:32:26 -08:00
Tejun Heo
839e3407d9 freezer: remove unused @sig_only from freeze_task()
After "freezer: make freezing() test freeze conditions in effect
instead of TIF_FREEZE", freezing() returns authoritative answer on
whether the current task should freeze or not and freeze_task()
doesn't need or use @sig_only.  Remove it.

While at it, rewrite function comment for freeze_task() and rename
@sig_only to @user_only in try_to_freeze_tasks().

This patch doesn't cause any functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:26 -08:00
Tejun Heo
37ad8aca94 freezer: use lock_task_sighand() in fake_signal_wake_up()
cgroup_freezer calls freeze_task() without holding tasklist_lock and,
if the task is exiting, its ->sighand may be gone by the time
fake_signal_wake_up() is called.  Use lock_task_sighand() instead of
accessing ->sighand directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Paul Menage <paul@paulmenage.org>
2011-11-21 12:32:26 -08:00
Tejun Heo
5ece3eae4c freezer: restructure __refrigerator()
If another freeze happens before all tasks leave FROZEN state after
being thawed, the freezer can see the existing FROZEN and consider the
tasks to be frozen but they can clear FROZEN without checking the new
freezing().

Oleg suggested restructuring __refrigerator() such that there's single
condition check section inside freezer_lock and sigpending is cleared
afterwards, which fixes the problem and simplifies the code.
Restructure accordingly.

-v2: Frozen loop exited without releasing freezer_lock.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
2011-11-21 12:32:26 -08:00
Tejun Heo
96ee6d8539 freezer: fix set_freezable[_with_signal]() race
A kthread doing set_freezable*() may race with on-going PM freeze and
the freezer might think all tasks are frozen while the new freezable
kthread is merrily proceeding to execute code paths which aren't
supposed to be executing during PM freeze.

Reimplement set_freezable[_with_signal]() using __set_freezable() such
that freezable PF flags are modified under freezer_lock and
try_to_freeze() is called afterwards.  This eliminates race condition
against freezing.

Note: Separated out from larger patch to resolve fix order dependency
      Oleg pointed out.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:25 -08:00
Tejun Heo
948246f70a freezer: remove should_send_signal() and update frozen()
should_send_signal() is only used in freezer.c.  Exporting them only
increases chance of abuse.  Open code the two users and remove it.

Update frozen() to return bool.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:25 -08:00
Tejun Heo
d88e4cb671 freezer: remove now unused TIF_FREEZE
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
2011-11-21 12:32:25 -08:00
Tejun Heo
a3201227f8 freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE
Using TIF_FREEZE for freezing worked when there was only single
freezing condition (the PM one); however, now there is also the
cgroup_freezer and single bit flag is getting clumsy.
thaw_processes() is already testing whether cgroup freezing in in
effect to avoid thawing tasks which were frozen by both PM and cgroup
freezers.

This is racy (nothing prevents race against cgroup freezing) and
fragile.  A much simpler way is to test actual freeze conditions from
freezing() - ie. directly test whether PM or cgroup freezing is in
effect.

This patch adds variables to indicate whether and what type of
freezing conditions are in effect and reimplements freezing() such
that it directly tests whether any of the two freezing conditions is
active and the task should freeze.  On fast path, freezing() is still
very cheap - it only tests system_freezing_cnt.

This makes the clumsy dancing aroung TIF_FREEZE unnecessary and
freeze/thaw operations more usual - updating state variables for the
new state and nudging target tasks so that they notice the new state
and comply.  As long as the nudging happens after state update, it's
race-free.

* This allows use of freezing() in freeze_task().  Replace the open
  coded tests with freezing().

* p != current test is added to warning printing conditions in
  try_to_freeze_tasks() failure path.  This is necessary as freezing()
  is now true for the task which initiated freezing too.

-v2: Oleg pointed out that re-freezing FROZEN cgroup could increment
     system_freezing_cnt.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul Menage <paul@paulmenage.org>  (for the cgroup portions)
2011-11-21 12:32:25 -08:00
Tejun Heo
22b4e111fa cgroup_freezer: prepare for removal of TIF_FREEZE
TIF_FREEZE will be removed soon and freezing() will directly test
whether any freezing condition is in effect.  Make the following
changes in preparation.

* Rename cgroup_freezing_or_frozen() to cgroup_freezing() and make it
  return bool.

* Make cgroup_freezing() access task_freezer() under rcu read lock
  instead of task_lock().  This makes the state dereferencing racy
  against task moving to another cgroup; however, it was already racy
  without this change as ->state dereference wasn't synchronized.
  This will be later dealt with using attach hooks.

* freezer->state is now set before trying to push tasks into the
  target state.

-v2: Oleg pointed out that freeze_change_state() was setting
     freeze->state incorrectly to CGROUP_FROZEN instead of
     CGROUP_FREEZING.  Fixed.

-v3: Matt pointed out that setting CGROUP_FROZEN used to always invoke
     try_to_freeze_cgroup() regardless of the current state.  Patch
     updated such that the actual freeze/thaw operations are always
     performed on invocation.  This shouldn't make any difference
     unless something is broken.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:25 -08:00
Tejun Heo
03afed8bc2 freezer: clean up freeze_processes() failure path
freeze_processes() failure path is rather messy.  Freezing is canceled
for workqueues and tasks which aren't frozen yet but frozen tasks are
left alone and should be thawed by the caller and of course some
callers (xen and kexec) didn't do it.

This patch updates __thaw_task() to handle cancelation correctly and
makes freeze_processes() and freeze_kernel_threads() call
thaw_processes() on failure instead so that the system is fully thawed
on failure.  Unnecessary [suspend_]thaw_processes() calls are removed
from kernel/power/hibernate.c, suspend.c and user.c.

While at it, restructure error checking if clause in suspend_prepare()
to be less weird.

-v2: Srivatsa spotted missing removal of suspend_thaw_processes() in
     suspend_prepare() and error in commit message.  Updated.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
2011-11-21 12:32:24 -08:00
Tejun Heo
376fede80e freezer: kill PF_FREEZING
With the previous changes, there's no meaningful difference between
PF_FREEZING and PF_FROZEN.  Remove PF_FREEZING and use PF_FROZEN
instead in task_contributes_to_load().

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:24 -08:00
Tejun Heo
85f1d47665 freezer: test freezable conditions while holding freezer_lock
try_to_freeze_tasks() and thaw_processes() use freezable() and
frozen() as preliminary tests before initiating operations on a task.
These are done without any synchronization and hinder with
synchronization cleanup without any real performance benefits.

In try_to_freeze_tasks(), open code self test and move PF_NOFREEZE and
frozen() tests inside freezer_lock in freeze_task().

thaw_processes() can simply drop freezable() test as frozen() test in
__thaw_task() is enough.

Note: This used to be a part of larger patch to fix set_freezable()
      race.  Separated out to satisfy ordering among dependent fixes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:24 -08:00
Tejun Heo
6907483b4e freezer: make freezing indicate freeze condition in effect
Currently freezing (TIF_FREEZE) and frozen (PF_FROZEN) states are
interlocked - freezing is set to request freeze and when the task
actually freezes, it clears freezing and sets frozen.

This interlocking makes things more complex than necessary - freezing
doesn't mean there's freezing condition in effect and frozen doesn't
match the task actually entering and leaving frozen state (it's
cleared by the thawing task).

This patch makes freezing indicate that freeze condition is in effect.
A task enters and stays frozen if freezing.  This makes PF_FROZEN
manipulation done only by the task itself and prevents wakeup from
__thaw_task() leaking outside of refrigerator.

The only place which needs to tell freezing && !frozen is
try_to_freeze_task() to whine about tasks which don't enter frozen.
It's updated to test the condition explicitly.

With the change, frozen() state my linger after __thaw_task() until
the task wakes up and exits fridge.  This can trigger BUG_ON() in
update_if_frozen().  Work it around by testing freezing() && frozen()
instead of frozen().

-v2: Oleg pointed out missing re-check of freezing() when trying to
     clear FROZEN and possible spurious BUG_ON() trigger in
     update_if_frozen().  Both fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Menage <paul@paulmenage.org>
2011-11-21 12:32:24 -08:00
Tejun Heo
0c9af09262 freezer: use dedicated lock instead of task_lock() + memory barrier
Freezer synchronization is needlessly complicated - it's by no means a
hot path and the priority is staying unintrusive and safe.  This patch
makes it simply use a dedicated lock instead of piggy-backing on
task_lock() and playing with memory barriers.

On the failure path of try_to_freeze_tasks(), locking is moved from it
to cancel_freezing().  This makes the frozen() test racy but the race
here is a non-issue as the warning is printed for tasks which failed
to enter frozen for 20 seconds and race on PF_FROZEN at the last
moment doesn't change anything.

This simplifies freezer implementation and eases further changes
including some race fixes.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:24 -08:00
Tejun Heo
6cd8dedcdd freezer: don't distinguish nosig tasks on thaw
There's no point in thawing nosig tasks before others.  There's no
ordering requirement between the two groups on thaw, which the staged
thawing can't guarantee anyway.  Simplify thaw_processes() by removing
the distinction and collapsing thaw_tasks() into thaw_processes().
This will help further updates to freezer.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:23 -08:00
Tejun Heo
a585042f7b freezer: remove racy clear_freeze_flag() and set PF_NOFREEZE on dead tasks
clear_freeze_flag() in exit_mm() is racy.  Freezing can start
afterwards.  Remove it.  Skipping freezer for exiting task will be
properly implemented later.

Also, freezable() was testing exit_state directly to make system
freezer ignore dead tasks.  Let the exiting task set PF_NOFREEZE after
entering TASK_DEAD instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:23 -08:00
Tejun Heo
a5be2d0d1a freezer: rename thaw_process() to __thaw_task() and simplify the implementation
thaw_process() now has only internal users - system and cgroup
freezers.  Remove the unnecessary return value, rename, unexport and
collapse __thaw_process() into it.  This will help further updates to
the freezer code.

-v3: oom_kill grew a use of thaw_process() while this patch was
     pending.  Convert it to use __thaw_task() for now.  In the longer
     term, this should be handled by allowing tasks to die if killed
     even if it's frozen.

-v2: minor style update as suggested by Matt.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Menage <menage@google.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
2011-11-21 12:32:23 -08:00