It's too large to be inlined.
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch (as1186) fixes a minor mistake in pci_enable_wake(). When
the routine is asked to disable remote wakeup, it should not return an
error merely because the device is not allowed to do wakeups!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch adds pci_swizzle_interrupt_pin(), which implements the
INTx swizzling algorithm specified in Table 9-1 of the "PCI-to-PCI
Bridge Architecture Specification," revision 1.2.
There are many architecture-specific implementations of this
swizzle that can be replaced by this common one.
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch makes pci_get_interrupt_pin() return values encoded
the same way as the "Interrupt Pin" value in PCI config space,
i.e., 1=INTA, ..., 4=INTD.
pirq_bios_set() is the only in-tree caller of pci_get_interrupt_pin()
and pci_get_interrupt_pin() is not exported.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: hpa@zytor.com
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Since interrupts will soon be disabled at PCI resume time, we need to
pre-allocate memory to save/restore PCI config space (or use GFP_ATOMIC,
but this is safer).
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Device drivers that use pci_request_regions() (and similar APIs) have a
reasonable expectation that they are the only ones accessing their device.
As part of the e1000e hunt, we were afraid that some userland (X or some
bootsplash stuff) was mapping the MMIO region that the driver thought it
had exclusively via /dev/mem or via various sysfs resource mappings.
This patch adds the option for device drivers to cause their reserved
regions to the "banned from /dev/mem use" list, so now both kernel memory
and device-exclusive MMIO regions are banned.
NOTE: This is only active when CONFIG_STRICT_DEVMEM is set.
In addition to the config option, a kernel parameter iomem=relaxed is
provided for the cases where developers want to diagnose, in the field,
drivers issues from userspace.
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The _OSC capability OSC_MSI_SUPPORT is set when the root bridge is added
with pci_acpi_osc_support(), so we no longer need to do it in the PCI
MSI driver. Also adds the function pci_msi_enabled, which returns true
if pci=nomsi is not on the kernel command-line.
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The _OSC capability OSC_EXT_PCI_CONFIG_SUPPORT is set when the root
bridge is added with pci_acpi_osc_support() if we can access PCI
extended config space.
This adds the function pci_ext_cfg_avail which returns true if we can
access PCI extended config space (offset greater than 0xff). It
currently only returns false if arch=x86 and raw_pci_ext_ops is not set
(which might happen if pci=nommcfg is set on the kernel command-line).
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Some PCI devices implement PCI Advanced Features, which means they
support Function Level Reset(FLR). Implement support for that in
pci_reset_function.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Separate out function level reset so that pci_reset_function can be more
easily extended.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
for fsck sake, it's used only when parsing kernel command line...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before initialization, dev->irq may be zero. Make sure we don't disable
it at reset time in that case.
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The original ARI support code has a compatibility problem with non-ARI
devices. If a device doesn't support ARI, turning on ARI forwarding on
its upper level bridge will cause undefined behavior.
This fix turns on ARI forwarding only when the subordinate devices
support it.
Tested-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Sometimes, it's necessary to enable software's ability to quiesce and
reset endpoint hardware with function-level granularity, so provide
support for it.
The patch implement Function Level Reset(FLR) feature following PCI-e
spec. And this is the first step. We would add more generic method, like
D0/D3, to allow more devices support this function.
The patch contains two functions. pcie_reset_function() is the new
driver API, and, contains some action to quiesce a device. The other
function is a helper: pcie_execute_reset_function() just executes the
reset for a particular device function.
Current the usage model is in KVM. Function reset is necessary for
assigning device to a guest, or moving it between partitions.
For Function Level Reset(FLR), please refer to PCI Express spec chapter
6.6.2.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Currently linux doesn't have any code to set the "MSI supported" bit in
Support Fireld of _OSC. This patch adds the code for that.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch adds support for PCI Express Alternative Routing-ID
Interpretation (ARI) capability.
The ARI capability extends the Function Number field of the PCI Express
Endpoint by reusing the Device Number which is otherwise hardwired to 0.
With ARI, an Endpoint can have up to 256 functions.
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This is a cleanup that changes all PCI configuration space size
representations to the macros (PCI_CFG_SPACE_SIZE and
PCI_CFG_SPACE_EXP_SIZE). And the macros are also moved from
drivers/pci/probe.c to drivers/pci/pci.h.
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Checkpatch would have complained about this but neither Bjorn nor myself
ran it prior to pushing. Fixup the issues Andrew pointed out.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch changes these two messages:
pci 0000:00:03.0: supports D1
pci 0000:00:03.0: supports D2
to this:
pci 0000:00:03.0: supports D1 D2
It also trivially converts a "dev_printk(KERN_INFO, ...)" to
"dev_info(...)".
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Many device drivers use the following sequence of statements to enable
the device to wake up the system while being in the D3_hot or D3_cold
low power state:
pci_enable_wake(pdev, PCI_D3hot, 1);
pci_enable_wake(pdev, PCI_D3cold, 1);
However, the second call is not necessary if the first one succeeds (the
ordering of the statements above doesn't matter here) and it may even be
harmful, because we are not supposed to enable PME# after the wake-up
power has been enabled for the device.
To allow drivers to overcome this problem, introduce function
pci_wake_from_d3() that will enable the device to wake up the system
from any of D3_hot and D3_cold as long as the wake-up from at least one
of them is supported.
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This converts things in drivers/pci to use %pR to printout the
content of a struct resource instead of hand-casted %llx or
other variants.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Export pci_pme_active() to drivers, so that they can clear the
PME_status bit and disable PME# for their devices without involving
ACPI.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Libata has some hacks to deal with certain controllers going silly in D3
state. The right way to handle this is to keep a PCI device flag for
such devices. That can then be generalised for no ATA devices with power
problems.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Make more PCI PM core functionality available to drivers
* Export pci_pme_capable() so that it can be called directly by
drivers (for example, tg3 needs that).
* Move the state choosing part of pci_prepare_to_sleep() to a
separate function, pci_target_state(), that can be called directly
by drivers (for example, tg3 needs that).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Fix kernel-doc comments so that they don't produce errors.
Also cut some extraneous copy-paste text.
Error(linhead//drivers/pci/pci.c:1133): duplicate section name 'Description'
Error(linhead//drivers/pci/pci.c:1189): duplicate section name 'Description'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/pci/pci.c needs pm_wakeup.h since it uses device_set_wakup_capable().
The latter also needs to be stubbed out for !CONFIG_PM.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The recently introduced pci_prepare_to_sleep() needs the following fix,
because there are systems which are not power manageable by ACPI (ie.
ACPI doesn't provide methods to put the device into low power states and
back), but require ACPI hooks to be executed for wake-up to work.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
If the offset of PCI device's PM capability in its configuration space,
the mask of states that the device supports PME# from and the D1 and D2
support bits are cached in the corresponding struct pci_dev, the PCI
device PM code can be simplified quite a bit.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Introduce functions pci_prepare_to_sleep() and pci_back_from_sleep(),
to be used by the PCI drivers that want to place their devices into
the lowest power state appropiate for them (PCI_D3hot, if the device
is not supposed to wake up the system, or the deepest state from
which the wake-up is possible, otherwise) while the system is being
prepared to go into a sleeping state and to put them back into D0
during the subsequent transition to the working state.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
* Introduce function acpi_pm_device_sleep_wake() for enabling and
disabling the system wake-up capability of devices that are power
manageable by ACPI.
* Introduce function acpi_bus_can_wakeup() allowing other (dependent)
subsystems to check if ACPI is able to enable the system wake-up
capability of given device.
* Introduce callback .sleep_wake() in struct pci_platform_pm_ops and
for the ACPI PCI 'driver' make it use acpi_pm_device_sleep_wake().
* Introduce callback .can_wakeup() in struct pci_platform_pm_ops and
for the ACPI 'driver' make it use acpi_bus_can_wakeup().
* Move the PME# handlig code out of pci_enable_wake() and split it
into two functions, pci_pme_capable() and pci_pme_active(),
allowing the caller to check if given device is capable of
generating PME# from given power state and to enable/disable the
device's PME# functionality, respectively.
* Modify pci_enable_wake() to use the new ACPI callbacks and the new
PME#-related functions.
* Drop the generic .platform_enable_wakeup() callback that is not
used any more.
* Introduce device_set_wakeup_capable() that will set the
power.can_wakeup flag of given device.
* Rework PCI device PM initialization so that, if given device is
capable of generating wake-up events, either natively through the
PME# mechanism, or with the help of the platform, its
power.can_wakeup flag is set and its power.should_wakeup flag is
unset as appropriate.
* Make ACPI set the power.can_wakeup flag for devices found to be
wake-up capable by it.
* Make the ACPI wake-up code enable/disable GPEs for devices that
have the wakeup.flags.prepared flag set (which means that their
wake-up power has been enabled).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Rework pci_set_power_state() so that the platform callback is
invoked before the native mechanism, if necessary. Also, make
the function check if the device is power manageable by the
platform before invoking the platform callback.
This may matter if the device dependent on additional power
resources controlled by the platform is being put into D0, in which
case those power resources must be turned on before we attempt to
handle the device itself.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Introduce function pointer platform_pci_power_manageable to be used
by the platform-related code to point to a function allowing us to
check if given device is power manageable by the platform.
Introduce acpi_pci_power_manageable() playing that role for ACPI.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Convert printks to use dev_printk().
I converted pr_debug() to dev_dbg(). Both use KERN_DEBUG and are enabled
only when DEBUG is defined.
I converted printk(KERN_DEBUG) to dev_printk(KERN_DEBUG), not to dev_dbg(),
because dev_dbg() is only enabled when DEBUG is defined.
I converted DBG(KERN_INFO) (only in setup-bus.c) to dev_info(). The DBG()
name makes it sound like debug, but it's been enabled forever, so dev_info()
preserves the previous behavior.
I tried to make the resource assignment formats more consistent, e.g.,
"BAR %d: got res [%#llx-%#llx] bus [%#llx-%#llx] flags %#lx\n"
instead of sometimes using "start-end" and sometimes using "size@start".
I'm not attached to one or the other; I'd just like them consistent.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Since the second argument of acpi_pci_choose_state() and
platform_pci_choose_state() is never used, remove it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
This patch removes CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
PCI Express ASPM defines a protocol for PCI Express components in the D0
state to reduce Link power by placing their Links into a low power state
and instructing the other end of the Link to do likewise. This
capability allows hardware-autonomous, dynamic Link power reduction
beyond what is achievable by software-only controlled power management.
However, The device should be configured by software appropriately.
Enabling ASPM will save power, but will introduce device latency.
This patch adds ASPM support in Linux. It introduces a global policy for
ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control
it. The interface can be used as a boot option too. Currently we have
below setting:
-default, BIOS default setting
-powersave, highest power saving mode, enable all available ASPM
state and clock power management
-performance, highest performance, disable ASPM and clock power
management
By default, the 'default' policy is used currently.
In my test, power difference between powersave mode and performance mode
is about 1.3w in a system with 3 PCIE links.
Note: some devices might not work well with aspm, either because chipset
issue or device issue. The patch provide API (pci_disable_link_state),
driver can disable ASPM for specific device.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Revert as it is reported to cause problems for people.
commit 4348a2dc49
Author: Shaohua Li <shaohua.li@intel.com>
Date: Wed Oct 24 10:45:08 2007 +0800
pcie: utilize pcie transaction pending bit
PCIE has a mechanism to wait for Non-Posted request to complete. I think
pci_disable_device is a good place to do this.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Due to the regression reported at
http://bugzilla.kernel.org/show_bug.cgi?id=10065
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Soeren Sonnenburg <kernel@nn7.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
During the last step of hibernation in the "platform" mode (with the
help of ACPI) we use the suspend code, including the devices'
->suspend() methods, to prepare the system for entering the ACPI S4
system sleep state.
But at least for some devices the operations performed by the
->suspend() callback in that case must be different from its operations
during regular suspend.
For this reason, introduce the new PM event type PM_EVENT_HIBERNATE and
pass it to the device drivers' ->suspend() methods during the last phase
of hibernation, so that they can distinguish this case and handle it as
appropriate. Modify the drivers that handle PM_EVENT_SUSPEND in a
special way and need to handle PM_EVENT_HIBERNATE in the same way.
These changes are necessary to fix a hibernation regression related
to the i915 driver (ref. http://lkml.org/lkml/2008/2/22/488).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds PCI's accessor for segment_boundary_mask in device_dma_parameters.
The default segment_boundary is set to 0xffffffff, same to the block layer's
default value (and the scsi mid layer uses the same value).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds struct device_dma_parameters in struct pci_dev and properly
sets up a pointer in struct device.
The default max_segment_size is set to 64K, same to the block layer's
default value.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Mostly-acked-by: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 6c723d5bd8.
It caused build errors on non-x86 platforms, config file confusion, and
even some boot errors on some x86-64 boxes. All around, not quite ready
for prime-time :(
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/pci-2.6: (64 commits)
PCI: make pci_bus a struct device
PCI: fix codingstyle issues in include/linux/pci.h
PCI: fix codingstyle issues in drivers/pci/pci.h
PCI: PCIE ASPM support
PCI: Fix fakephp deadlock
PCI: modify SB700 SATA MSI quirk
PCI: Run ACPI _OSC method on root bridges only
PCI ACPI: AER driver should only register PCIe devices with _OSC
PCI ACPI: Added a function to register _OSC with only PCIe devices.
PCI: constify function pointer tables
PCI: Convert drivers/pci/proc.c to use unlocked_ioctl
pciehp: block new requests from the device before power off
pciehp: workaround against Bad DLLP during power off
pciehp: wait for 1000ms before LED operation after power off
PCI: Remove pci_enable_device_bars() from documentation
PCI: Remove pci_enable_device_bars()
PCI: Remove users of pci_enable_device_bars()
PCI: Add pci_enable_device_{io,mem} intefaces
PCI: avoid save the same type of cap multiple times
PCI: correctly initialize a structure for pcie_save_pcix_state()
...
PCI Express ASPM defines a protocol for PCI Express components in the D0
state to reduce Link power by placing their Links into a low power state
and instructing the other end of the Link to do likewise. This
capability allows hardware-autonomous, dynamic Link power reduction
beyond what is achievable by software-only controlled power management.
However, The device should be configured by software appropriately.
Enabling ASPM will save power, but will introduce device latency.
This patch adds ASPM support in Linux. It introduces a global policy for
ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control
it. The interface can be used as a boot option too. Currently we have
below setting:
-default, BIOS default setting
-powersave, highest power saving mode, enable all available ASPM
state
and clock power management
-performance, highest performance, disable ASPM and clock power
management
By default, the 'default' policy is used currently.
In my test, power difference between powersave mode and performance mode
is about 1.3w in a system with 3 PCIE links.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Now that all in-tree users are gone, this removes pci_enable_device_bars()
completely.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The pci_enable_device_bars() interface isn't well suited to PCI
because you can't actually enable/disable BARs individually on
a device. So for example, if a device has 2 memory BARs 0 and 1,
and one of them (let's say 1) has not been successfully allocated
by the firmware or the kernel, then enabling memory decoding
shouldn't be permitted for the entire device since it will decode
whatever random address is still in that BAR 1.
So a device must be either fully enabled for IO, for Memory, or
for both. Not on a per-BAR basis.
This provides two new functions, pci_enable_device_io() and
pci_enable_device_mem() to replace pci_enable_device_bars(). The
implementation internally builds a BAR mask in order to be able
to use existing arch infrastructure.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Avoid adding the same type of cap multiple times, otherwise we will see dead loop.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Andrew Morton