summaryrefslogtreecommitdiffstats
path: root/include/linux/power_supply.h
AgeCommit message (Collapse)Author
2014-05-30power_supply: allow power supply devices registered w/o wakeup sourceZhang Rui
Currently, all the power supply devices are registered with wakeup source, this results in that every power_supply_changed() invocation brings the system out of suspend-to-freeze state. This is overkill as some device drivers, e.g. ACPI battery driver, have the ability to check the device status and wake up the system from sleeping only when necessary. Thus introduce a new API which allows device to be registered w/o wakeup source. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-23power_supply: Add power_supply_get_by_phandleSebastian Reichel
Add method to get power supply by device tree phandle. Signed-off-by: Sebastian Reichel <sre@debian.org> Reviewed-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-12-01power_supply: Add power_supply notifierPali Rohár
This patch adds a notifier chain to the power_supply, this helps drivers in other subsystem to listen to changes in power supply subsystem. This would help to take some actions in those drivers on changing the power supply properties. One such scenario is to increase/decrease system performance based on the battery capacity/voltage. Another scenario is to adjust the h/w peak current detection voltage/current thresholds based on battery voltage/capacity. The notifier helps drivers to listen to changes in power_suppy susbystem without polling the power_supply properties Signed-off-by: Jenny TC <jenny.tc@intel.com> Signed-off-by: Pali Rohár <pali.rohar@gmail.com> Acked-by: Jenny TC <jenny.tc@intel.com> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-08-27power_supply: Prevent suspend until power supply events are processedZoran Markovic
This patch, originally authored by Arve Hjonnevag and Todd Poynor, prevents the system from entering suspend mode until the power supply plug, unplug, or any other change of state event is fully processed. This guarantees that the screen lights up and displays the battery charging state. The implementation uses the power supply wakeup_source object. Cc: David Woodhouse <dwmw2@infradead.org> Cc: Arve Hjonnevag <arve@android.com> Cc: Todd Poynor <toddpoynor@google.com> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-06-28power_supply: Move of_node out of the #ifdef CONFIG_OFAnton Vorontsov
Similar to linux/device.h, move of_node struct member out of the #ifdef CONFIG_OF so that the drivers won't have to mess with #ifdefs in .c files. Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-04-16power_supply: Populate supplied_from hierarchy from the device treeRhyland Klein
With this patch the power_supply_core will try to populate supplied_from hierarchy from the device tree. Signed-off-by: Rhyland Klein <rklein@nvidia.com> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-04-16power_supply: Add core support for supplied_fromRhyland Klein
This patch adds support for supplies to register a list of char *'s which represent the list of supplies which supply them. This is the opposite as the supplied_to list. This change maintains support for supplied_to until all drivers which make use of it already are converted. Signed-off-by: Rhyland Klein <rklein@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2013-02-21Merge tag 'driver-core-3.9-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core patches from Greg Kroah-Hartman: "Here is the big driver core merge for 3.9-rc1 There are two major series here, both of which touch lots of drivers all over the kernel, and will cause you some merge conflicts: - add a new function called devm_ioremap_resource() to properly be able to check return values. - remove CONFIG_EXPERIMENTAL Other than those patches, there's not much here, some minor fixes and updates" Fix up trivial conflicts * tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (221 commits) base: memory: fix soft/hard_offline_page permissions drivercore: Fix ordering between deferred_probe and exiting initcalls backlight: fix class_find_device() arguments TTY: mark tty_get_device call with the proper const values driver-core: constify data for class_find_device() firmware: Ignore abort check when no user-helper is used firmware: Reduce ifdef CONFIG_FW_LOADER_USER_HELPER firmware: Make user-mode helper optional firmware: Refactoring for splitting user-mode helper code Driver core: treat unregistered bus_types as having no devices watchdog: Convert to devm_ioremap_resource() thermal: Convert to devm_ioremap_resource() spi: Convert to devm_ioremap_resource() power: Convert to devm_ioremap_resource() mtd: Convert to devm_ioremap_resource() mmc: Convert to devm_ioremap_resource() mfd: Convert to devm_ioremap_resource() media: Convert to devm_ioremap_resource() iommu: Convert to devm_ioremap_resource() drm: Convert to devm_ioremap_resource() ...
2013-02-06driver-core: constify data for class_find_device()Michał Mirosław
All in-kernel users of class_find_device() don't really need mutable data for match callback. In two places (kernel/power/suspend_test.c, drivers/scsi/osd/osd_uld.c) this patch changes match callbacks to use const search data. The const is propagated to rtc_class_open() and power_supply_get_by_name() parameters. Note that there's a dev reference leak in suspend_test.c that's not touched in this patch. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-05power_supply: Add watchdog and safety timer expiries under PROP_HEALTH_*Ramakrishna Pallala
As most of the charger chips come with two kinds of safety features related to timing: 1. Watchdog Timer (interms of seconds/mins) 2. Safety Timer (interms of hours) This patch adds these to fault causes in POWER_SUPPLY_PROP_HEALTH_* enums so that whenever there is either watchdog timeout or safety timer timeout driver could notify the user space accurately about the fault and will also be helpful for debug. Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
2012-11-17power_supply: Register power supply for thermal cooling deviceRamakrishna Pallala
This patch registers the power supply as a cooling device if the power supply has support for charge throttling. Now with this change low level drivers need not register with thermal framework as it is automatically done by power supply framework. Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-11-17power_supply: Add support for CHARGE_CONTROL_* attributesRamakrishna Pallala
Add support for power supply attributes CHARGE_CONTROL_LIMIT and CHARGE_CONTROL_LIMIT_MAX. These new attributes will enable the user space to implement custom charging algorithms based on platform state. Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-08-22power_supply: Add new power supply properties CHARGE_CURRENT/VOLTAGE_MAXRamakrishna Pallala
There are different types of chargers avalibale like AC, Solar, USB, etc.. Even in USB we have different types SDP/DCP/CDP/ACA and all these chargers have different o/p ratings. For example SDP supports only 500mA of charge current whereas AC charger can support upto 8A or more. Similarly batteries also come with charge current and voltage ratings and these ratings vary depending on its capacity and the technology used. This patch adds two new power supply properties CONSTANT_CHARGE_CURRENT_MAX and CONSTANT_CHARGE_CURRENT_MAX. Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-08-22power_supply: Add new power supply AUTHENTIC propertyRamakrishna Pallala
It is possible that users can use non-standard chargers or use invalid batteries especially with mobile devices. This patch adds a new power supply property called 'AUTHENTIC' to indicate this to the user(user space). Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-07-13power_supply: Add min/max alert properties for CAPACITY, TEMP, TEMP_AMBIENTRamakrishna Pallala
Minimum and maximum alerts on power supply properties will help or allow the user space to "proactively" create policies like connect/disconnect charger or stop/start the user apps based on capacity or temperature parameters. These parameters can be used to avoid unnecessary polling from user space and even from kernel space if the underlying HW can support INT triggers (ex: max17042/47). This patch adds the following power supply alert type properties: CAPACITY_ALERT_MIN CAPACITY_ALERT_MAX TEMP_ALERT_MIN TEMP_ALERT_MAX TEMP_AMBIENT_ALERT_MIN TEMP_AMBIENT_ALERT_MAX Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-06-19power_supply: Add constant charge_current and charge_voltage propertiesRamakrishna Pallala
Constant Charge Current(CC) is charging parameter which limit the maximum current which can be pumped into the battery during charge cycle. Constant Charge Voltage(CV) is also charging parameter which limit the maximum voltage that battery can reach during charge cycle. It is very common practice that at low or high temperatures we do not charge the batteries upto it's fullest charge voltage to avoid battery and user safety issues. These sysfs properties will be useful for debug and to implement certain user space policies like "Charging limited due to OverTemp". Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2012-06-17power_supply: Register battery as a thermal zoneJenny TC
Battery and charger contribute to Thermals in most of the embedded devices. So, it makes sense to identify them as Thermal zones in a particular platform. This patch registers a thermal zone if the power supply is reporting a temperature property. The thermal zone will be used by platform's thermal management solution. Signed-off-by: Jenny TC <jenny.tc@intel.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2012-05-04power_supply: Make the core a boolean instead of a tristateAnton Vorontsov
On Mon, Apr 02, 2012 at 01:53:23PM +1000, Benjamin Herrenschmidt wrote: > > drivers/built-in.o: In function `.nouveau_pm_trigger': > > (.text+0xa56e8): undefined reference to `.power_supply_is_system_supplied' > > > > nouveau probably needs to depends on CONFIG_POWER_SUPPLY to force a module > > build with the latter is =m > > Ok, not that trivial... > > The problem is more like POWER_SUPPLY should be a bool, not a tristate. > > If you think about it: you don't want things like nouveau to depend on a > random subsystem like that, people will never get it. In fact, > POWER_SUPPLY provides empty inline stubs when not enabled, so that's > really designed to not have depends... > > However that -cannot- work if POWER_SUPPLY is modular and the drivers > who use it are not. > > The only fixes here that make sense I can think of > that don't also involve Kconfig horrors are: > > - Ugly: in power_supply.h, use the extern variant if > > defined(CONFIG_POWER_SUPPLY) || > (defined(CONFIG_POWER_SUPPLY_MODULE) && defined(MODULE)) > > IE. use the stub if power supply is a module and what is being built is > built-in. Of course that's not only ugly, it somewhat sucks from a user > perspective as the subsystem now exists but can't be used by some > drivers... > > - Better: Just make the bloody thing a bool :-) The power supply > framework itself is small enough, just make it a boolean option and > avoid the problem entirely. The actual power supply sub drivers can > remain modular of course. Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2012-05-04power_supply: Add voltage_ocv property and use it for max17042 driverRamakrishna Pallala
This adds a new sysfs file called 'voltage_ocv' which gives the Open Circuit Voltage of the battery. This property can be used for platform shutdown policies and can be useful for initial capacity estimations. Note: This patch is generated against linux-next branch. Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-03-16device.h: audit and cleanup users in main include dirPaul Gortmaker
The <linux/device.h> header includes a lot of stuff, and it in turn gets a lot of use just for the basic "struct device" which appears so often. Clean up the users as follows: 1) For those headers only needing "struct device" as a pointer in fcn args, replace the include with exactly that. 2) For headers not really using anything from device.h, simply delete the include altogether. 3) For headers relying on getting device.h implicitly before being included themselves, now explicitly include device.h 4) For files in which doing #1 or #2 uncovers an implicit dependency on some other header, fix by explicitly adding the required header(s). Any C files that were implicitly relying on device.h to be present have already been dealt with in advance. Total removals from #1 and #2: 51. Total additions coming from #3: 9. Total other implicit dependencies from #4: 7. As of 3.3-rc1, there were 110, so a net removal of 42 gives about a 38% reduction in device.h presence in include/* Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-01-04Merge branch 'power-supply-scope' of ↵Anton Vorontsov
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
2012-01-04power_supply: Add "unknown" in power supply typeKim, Milo
For the default value of power supply type, "unknown" is added. With default prop value, supply type property can be displayed as default - "Unknown". Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2011-12-09power_supply: allow a power supply to explicitly point to powered deviceJeremy Fitzhardinge
If a power supply has a scope of "Device", then allow the power supply to indicate what device it actually powers. This is represented in the power supply's sysfs directory as a symlink named "powers", which points to the sysfs directory of the powered device. If the device has children, then the sub-devices are also powered by the same power supply. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Richard Hughes <richard@hughsie.com>
2011-12-09power_supply: add SCOPE attribute to power suppliesJeremy Fitzhardinge
This adds a "scope" attribute to a power_supply, which indicates how much of the system it powers. It appears in sysfs as "scope" or in the uevent file as POWER_SUPPLY_SCOPE=. There are presently three possible values: Unknown - unknown power topology System - the power supply powers the whole system Device - it powers a specific device, or tree of devices A power supply which doesn't have a "scope" attribute should be assumed to have "System" scope. In general, usermode should assume that loss of all System-scoped power supplies will power off the whole system, but any single one is sufficient to power the system. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Richard Hughes <richard@hughsie.com>
2011-03-01power_supply: Update power_supply_is_watt_propertyRhyland Klein
Update the power_supply_is_watt_property function to include POWER_NOW. Signed-off-by: Rhyland Klein <rklein@nvidia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2011-01-31power_supply: Add new LED trigger charging-blink-solid-fullVasily Khoruzhick
Add new trigger to power_supply LEDs. It will blink when battery is charging, and stay solid when battery is charged. It's usefull to indicate battery state when there's only one LED available. Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2011-01-31bq20z75: Add support for charge propertiesRhyland Klein
Adding support for charge properties for gas gauge. Also ensuring that battery mode is correct now for energy as well as charge properties by setting it on the fly. I also added 2 functions to power_supply.h to help identify the units for specific properties more easily by power supplies. Signed-off-by: Rhyland Klein <rklein@nvidia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2010-10-06power_supply: Introduce maximum current propertyHeikki Krogerus
USB only gives the maximum current allowed to draw. Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@nokia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2010-10-06power_supply: Add types for USB chargersHeikki Krogerus
This adds power supply types for USB chargers defined in Battery Charging Specification 1.1. Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@nokia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2010-05-19power_supply: Add support for writeable propertiesDaniel Mack
This patch adds support for writeable power supply properties and exposes them as writeable to sysfs. A power supply implementation must implement two new function calls in order to use that feature: int set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val); int property_is_writeable(struct power_supply *psy, enum power_supply_property psp); Signed-off-by: Daniel Mack <daniel@caiaq.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Alexey Starikovskiy <astarikovskiy@suse.de> Cc: Len Brown <len.brown@intel.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Matt Reimer <mreimer@vpop.net> Cc: Evgeniy Polyakov <zbr@ioremap.net> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2010-05-19power_supply: Use attribute groupsAnton Vorontsov
This fixes a race between power supply device and initial attributes creation, plus makes it possible to implement writable properties. [Daniel Mack - removed superflous return statement and dropped .mode attribute from POWER_SUPPLY_ATTR] Suggested-by: Greg KH <gregkh@suse.de> Suggested-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com> Tested-by: Daniel Mack <daniel@caiaq.de>
2010-01-15POWER: Add support for cycle_countAlexey Starikovskiy
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de> Signed-off-by: Len Brown <len.brown@intel.com>
2009-07-30power_supply: get_by_name and set_charged functionalityDaniel Mack
This adds a function that indicates that a battery is fully charged. It also includes functions to get a power_supply device from the class of registered devices by name reference. These can be used to find a specific battery to call power_supply_set_battery_charged() on. Some battery drivers might need this information to calibrate themselves. Signed-off-by: Daniel Mack <daniel@caiaq.de> Cc: Ian Molton <spyro@f2s.com> Cc: Anton Vorontsov <cbou@mail.ru> Cc: Matt Reimer <mreimer@vpop.net> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2009-07-02power_supply: Add a charge_type property, and use it for olpc driverAndres Salomon
This adds a new sysfs file called 'charge_type' which displays the type of charging (unknown, n/a, trickle charge, or fast charging). This allows things like battery diagnostics to determine what the battery/EC is doing without resorting to changing the 'status' sysfs output. Signed-off-by: Andres Salomon <dilinger@collabora.co.uk> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2009-07-01Revert "power: remove POWER_SUPPLY_PROP_CAPACITY_LEVEL"Andres Salomon
This reverts commit 8efe444038a205e79b38b7ad03878824901849a8 and 4cbc76eadf56399cd11fb736b33c53aec9caab8c. Richard@laptop.org was apparently using CAPACITY_LEVEL for debugging battery/EC problems, and was upset that it was removed. This readds it. Conflicts: Documentation/power_supply_class.txt Signed-off-by: Andres Salomon <dilinger@collabora.co.uk> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2009-03-27ACPI: battery: add power_{now,avg} properties to power_classAlexey Starikovskiy
ACPI has smart batteries, which work in units of energy and measure rate of (dis)charge as power, thus it is not appropriate to export it as a current_now. Current_now will still be exported to allow for userland applications to match. Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de> Signed-off-by: Len Brown <len.brown@intel.com>
2009-01-04power_supply: Add cold to the POWER_SUPPLY_HEALTH report valuesMark Brown
Some systems are able to report problems with batteries being under temperature. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
2008-09-01power_supply: Add function to return system-wide power stateMatthew Garrett
Certain drivers benefit from knowing whether the system is on ac or battery, for instance when determining which backlight registers to read. This adds a simple call to determine whether there's an online power supply other than any batteries. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2008-05-13power_supply: add CHARGE_COUNTER property and olpc_battery support for itAndres Salomon
This adds PROP_CHARGE_COUNTER to the power supply class (documenting it as well). The OLPC battery driver uses this for spitting out its ACR values (in uAh). We have some rounding errors (the data sheet claims 416.7, the math actually works out to 416.666667, so we're forced to choose between overflows or precision loss. I chose precision loss, and stuck w/ data sheet values), but I don't think anyone will care that much. Signed-off-by: Andres Salomon <dilinger@debian.org> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2008-02-05ACPI: battery: add sysfs serial numbermaximilian attems
egrep serial /proc/acpi/battery/BAT0/info serial number: 32090 serial number can tell you from the imminent danger of beeing set on fire. Signed-off-by: maximilian attems <max@stro.at> Acked-by: Alexey Starikovskiy <astarikovskiy@suse.de> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-02power_supply: add few more values and propsDmitry Baryshkov
Add LiMn (one of the most common for small non-rechargable batteries) battery technology and voltage_min/_max properties support. Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com> Signed-off-by: Anton Vorontsov <cbou@mail.ru>
2008-02-02power: remove POWER_SUPPLY_PROP_CAPACITY_LEVELAndres Salomon
The CAPACITY_LEVEL stuff defines various levels of charge; however, what is the difference between them? What differentiates between HIGH and NORMAL, LOW and CRITICAL, etc? As it appears that these are fairly arbitrary, we end up making such policy decisions in the kernel (or in hardware). This is the sort of decision that should be made in userspace, not in the kernel. If the hardware does not support _CAPACITY and it cannot be easily calculated, then perhaps the driver should register a custom CAPACITY_LEVEL attribute; however, userspace should not become accustomed to looking for such a thing, and we should certainly not encourage drivers to provide CAPACITY_LEVEL stubs. The following removes support for POWER_SUPPLY_PROP_CAPACITY_LEVEL. The OLPC battery driver is the only driver making use of this, so it's removed from there as well. Signed-off-by: Andres Salomon <dilinger@debian.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-07-10[BATTERY] Universal power supply class (was: battery class)Anton Vorontsov
This class is result of "external power" and "battery" classes merge, as suggested by David Woodhouse. He also implemented uevent support. Here how userspace seeing it now: # ls /sys/class/power\ supply/ ac main-battery usb # cat /sys/class/power\ supply/ac/type AC # cat /sys/class/power\ supply/usb/type USB # cat /sys/class/power\ supply/main-battery/type Battery # cat /sys/class/power\ supply/ac/online 1 # cat /sys/class/power\ supply/usb/online 0 # cat /sys/class/power\ supply/main-battery/status Charging # cat /sys/class/leds/h5400\:red-left/trigger none h5400-radio timer hwtimer ac-online usb-online main-battery-charging-or-full [main-battery-charging] main-battery-full Signed-off-by: Anton Vorontsov <cbou@mail.ru> Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>