Multiple race conditions are possible between PCI hotplug and the generic
PCI bus rescan and device removal that can be triggered via sysfs.

To avoid those race conditions make PCI hotplug use global PCI
rescan-remove locking.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Multiple race conditions are possible between the ACPI-based PCI hotplug
(ACPIPHP) and the generic PCI bus rescan and device removal that can be
triggered via sysfs.

To avoid those race conditions make the ACPIPHP code use global PCI
rescan-remove locking.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Using 'make namespacecheck' identify code which should be declared static.
Checked for users in other driver/archs as well.  Compile tested only.

This stops exporting the following interfaces to modules:

    pci_target_state()
    pci_load_saved_state()

[bhelgaas: retained pci_find_next_ext_capability() and pci_cfg_space_size()]
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made
during the 3.12 development cycle uncovered a problem with VGA
switcheroo that on some systems, when the device-specific method
(ATPX in the radeon case, _DSM in the nouveau case) is used to turn
off the discrete graphics, the BIOS generates ACPI hotplug events for
that device and those events cause ACPIPHP to attempt to remove the
device from the system (they are events for a device that was present
previously and is not present any more, so that's what should be done
according to the spec).  Then, the system stops functioning correctly.

Since the hotplug events in question were simply silently ignored
previously, the least intrusive way to address that problem is to
make ACPIPHP ignore them again.  For this purpose, introduce a new
ACPI device flag, no_hotplug, and modify ACPIPHP to ignore hotplug
events for PCI devices whose ACPI companions have that flag set.
Next, make the radeon and nouveau switcheroo detection code set the
no_hotplug flag for the discrete graphics' ACPI companion.

Fixes: bbd34fcd (ACPI / hotplug / PCI: Register all devices under the given bridge)
References: https://bugzilla.kernel.org/show_bug.cgi?id=61891
References: https://bugzilla.kernel.org/show_bug.cgi?id=64891Reported-and-tested-by: NMike Lothian <mike@fireburn.co.uk>
Reported-and-tested-by: <madcatx@atlas.cz>
Reported-and-tested-by: NJoaquín Aramendía <samsagax@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+

Previously, the caller checked ATTN_LED() or PWR_LED() to see whether the
slot has indicators before setting the indicator state.  That clutters the
caller unnecessarily, so this moves the test inside the callees.  The test
may not even be necessary; per spec it should be harmless to try to turn on
a non-existent LED.  But checking first does avoid unnecessary hotplug
commands.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add symbolic constants for the PCIe Slot Control indicator and power
control fields defined by spec and use them instead of open-coded hex
constants.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use the PCI_EXP_SLTSTA definitions, not 0x1f, when clearing Slot Status
bits.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

It's simpler to test the PCI_EXP_SLTSTA_PFD bit directly and to write the
constant back to PCI_EXP_SLTSTA.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

We already have the vendor/device IDs from pci_setup_device(), so drop that
info and print things that will be more useful for debugging: the slot
number and presence of button/indicators/link active reporting/etc.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

These functions:

  pcie_enable_notification()
  pciehp_power_off_slot()
  pciehp_get_power_status()
  pciehp_get_attention_status()
  pciehp_set_attention_status()
  pciehp_get_latch_status()
  pciehp_get_adapter_status()
  pcie_write_cmd()

now always return success, so this patch makes them void and drops the
error-checking code in their callers.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

There's not much point in checking the return value from every config space
access because the only likely errors are design-time things like unaligned
accesses or invalid register numbers.  The checking clutters the code
significantly, so this patch removes it.

No functional change.

Reference: http://lkml.kernel.org/r/CA+55aFzP4xEbcNmZ+MS0SQ3LrULzSq+dBiT_X9U-bPpR-Ukgrw@mail.gmail.comSigned-off-by: NBjorn Helgaas <bhelgaas@google.com>

The pciehp_readw() and pciehp_writew() wrappers only look up the pci_dev
and call the PCIe Capability accessors, so we can make things a little
more straightforward by just using the PCIe Capability accessors directly.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Replace direct inclusions of <acpi/acpi.h>, <acpi/acpi_bus.h> and
<acpi/acpi_drivers.h>, which are incorrect, with <linux/acpi.h>
inclusions and remove some inclusions of those files that aren't
necessary.

First of all, <acpi/acpi.h>, <acpi/acpi_bus.h> and <acpi/acpi_drivers.h>
should not be included directly from any files that are built for
CONFIG_ACPI unset, because that generally leads to build warnings about
undefined symbols in !CONFIG_ACPI builds.  For CONFIG_ACPI set,
<linux/acpi.h> includes those files and for CONFIG_ACPI unset it
provides stub ACPI symbols to be used in that case.

Second, there are ordering dependencies between those files that always
have to be met.  Namely, it is required that <acpi/acpi_bus.h> be included
prior to <acpi/acpi_drivers.h> so that the acpi_pci_root declarations the
latter depends on are always there.  And <acpi/acpi.h> which provides
basic ACPICA type declarations should always be included prior to any other
ACPI headers in CONFIG_ACPI builds.  That also is taken care of including
<linux/acpi.h> as appropriate.
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (drivers/pci stuff)
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> (Xen stuff)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpiphp_enumerate_slots() walks ACPI namenamespace under
a PCI host bridge with callback register_slot().
register_slot() evaluates _ADR for all the device objects
and emits a warning message for any error.  Some platforms
have _HID device objects (such as HPET and IPMI), which
trigger unnecessary warning messages.

This patch avoids emitting a warning message when a target
device object does not have _ADR.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Modify the ACPI namespace scanning code to register a struct
acpi_device object for every namespace node representing a device,
processor and so on, even if the device represented by that namespace
node is reported to be not present and not functional by _STA.

There are multiple reasons to do that.  First of all, it avoids
quite a lot of overhead when struct acpi_device objects are
deleted every time acpi_bus_trim() is run and then added again
by a subsequent acpi_bus_scan() for the same scope, although the
namespace objects they correspond to stay in memory all the time
(which always is the case on a vast majority of systems).

Second, it will allow user space to see that there are namespace
nodes representing devices that are not present at the moment and may
be added to the system.  It will also allow user space to evaluate
_SUN for those nodes to check what physical slots the "missing"
devices may be put into and it will make sense to add a sysfs
attribute for _STA evaluation after this change (that will be
useful for thermal management on some systems).

Next, it will help to consolidate the ACPI hotplug handling among
subsystems by making it possible to store hotplug-related information
in struct acpi_device objects in a standard common way.

Finally, it will help to avoid a race condition related to the
deletion of ACPI namespace nodes.  Namely, namespace nodes may be
deleted as a result of a table unload triggered by _EJ0 or _DCK.
If a hotplug notification for one of those nodes is triggered
right before the deletion and it executes a hotplug callback
via acpi_hotplug_execute(), the ACPI handle passed to that
callback may be stale when the callback actually runs.  One way
to work around that is to always pass struct acpi_device pointers
to hotplug callbacks after doing a get_device() on the objects in
question which eliminates the use-after-free possibility (the ACPI
handles in those objects are invalidated by acpi_scan_drop_device(),
so they will trigger ACPICA errors on attempts to use them).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Commit bd950799 (PCI: acpiphp: Convert to dynamic debug) removed users
of acpiphp_debug variable and the variable itself but the declaration was
left in the header file. Drop this unused declaration.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Since DEVICE_ACPI_HANDLE() is now literally identical to
ACPI_HANDLE(), replace it with the latter everywhere and drop its
definition from include/acpi.h.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Modify struct acpi_dev_node to contain a pointer to struct acpi_device
associated with the given device object (that is, its ACPI companion
device) instead of an ACPI handle corresponding to it.  Introduce two
new macros for manipulating that pointer in a CONFIG_ACPI-safe way,
ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the
ACPI_HANDLE() macro to take the above changes into account.
Drop the ACPI_HANDLE_SET() macro entirely and rework its users to
use ACPI_COMPANION_SET() instead.  For some of them who used to
pass the result of acpi_get_child() directly to ACPI_HANDLE_SET()
introduce a helper routine acpi_preset_companion() doing an
equivalent thing.

The main motivation for doing this is that there are things
represented by struct acpi_device objects that don't have valid
ACPI handles (so called fixed ACPI hardware features, such as
power and sleep buttons) and we would like to create platform
device objects for them and "glue" them to their ACPI companions
in the usual way (which currently is impossible due to the
lack of valid ACPI handles).  However, there are more reasons
why it may be useful.

First, struct acpi_device pointers allow of much better type checking
than void pointers which are ACPI handles, so it should be more
difficult to write buggy code using modified struct acpi_dev_node
and the new macros.  Second, the change should help to reduce (over
time) the number of places in which the result of ACPI_HANDLE() is
passed to acpi_bus_get_device() in order to obtain a pointer to the
struct acpi_device associated with the given "physical" device,
because now that pointer is returned by ACPI_COMPANION() directly.
Finally, the change should make it easier to write generic code that
will build both for CONFIG_ACPI set and unset without adding explicit
compiler directives to it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> # on Haswell
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com> # for ATA and SDIO part

Fix whitespace, capitalization, and spelling errors.  No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.

Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are two different interfaces for queuing up work items on the
ACPI hotplug workqueue, alloc_acpi_hp_work() used by PCI and PCI host
bridge hotplug code and acpi_os_hotplug_execute() used by the common
ACPI hotplug code and docking stations.  They both are somewhat
cumbersome to use and work slightly differently.

The users of alloc_acpi_hp_work() have to submit a work function that
will extract the necessary data items from a struct acpi_hp_work
object allocated by alloc_acpi_hp_work() and then will free that
object, while it would be more straightforward to simply use a work
function with one more argument and let the interface take care of
the execution details.

The users of acpi_os_hotplug_execute() also have to deal with the
fact that it takes only one argument in addition to the work function
pointer, although acpi_os_execute_deferred() actually takes care of
the allocation and freeing of memory, so it would have been able to
pass more arguments to the work function if it hadn't been
constrained by the connection with acpi_os_execute().

Moreover, while alloc_acpi_hp_work() makes GFP_KERNEL memory
allocations, which is correct, because hotplug work items are
always queued up from process context, acpi_os_hotplug_execute()
uses GFP_ATOMIC, as that is needed by acpi_os_execute().  Also,
acpi_os_execute_deferred() queued up by it waits for the ACPI event
workqueues to flush before executing the work function, whereas
alloc_acpi_hp_work() can't do anything similar.  That leads to
somewhat arbitrary differences in behavior between various ACPI
hotplug code paths and has to be straightened up.

For this reason, replace both alloc_acpi_hp_work() and
acpi_os_hotplug_execute() with a single interface,
acpi_hotplug_execute(), combining their behavior and being more
friendly to its users than any of the two.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Commit 2dc41281 (ACPI / hotplug / PCI: Avoid doing too much for
spurious notifies) changed the enable_slot() to check return value of
pci_scan_slot() and if it is zero return early from the function. It
means that there were no new devices in this particular slot.

However, if a device appeared deeper in the hierarchy the code now
ignores it causing things like Thunderbolt chaining fail to recognize
new devices.

The problem with Alex Williamson's machine was solved with commit
a47d8c8e (ACPI / hotplug / PCI: Avoid parent bus rescans on spurious
device checks) and hence we should be able to restore the original
functionality that we always rescan on bus check notification.

On a device check notification we still check what acpiphp_rescan_slot()
returns and on zero bail out early.

Fixes: 2dc41281 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies)
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Cleanup arch specific pci messages. Remove unhelpful messages and
replace others with entries in the debugfs.
Reviewed-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The WARN_ON() in acpiphp_enumerate_slots() triggers unnecessarily for
devices whose bridges are going to be handled by native PCIe hotplug
(pciehp) and the simplest way to prevent that from happening is to
drop the WARN_ON().

References: https://bugzilla.kernel.org/show_bug.cgi?id=62831Reported-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

One of the error code paths in acpiphp_enumerate_slots() is missing
a pci_dev_put(bridge->pci_dev) call, so add it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>

This patch is to use pr_debug/info/warn/err to replace acpiphp_ibm debug
functions and remove module's debug param.

User interface change: before this patch, boot with the "acpiphp_ibm.debug"
kernel parameter to turn on debug.  After this patch, set
CONFIG_DYNAMIC_DEBUG=y and boot with "acpiphp_ibm.dyndebug=+p" instead.
See Documentation/dynamic-debug-howto.txt.

[bhelgaas: changelog]
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This patch is to use pr_debug/info/warn/err to replace acpiphp debug
functions and remove module's debug param.

User interface change: before this patch, boot with the "acpiphp.debug"
kernel parameter to turn on debug.  After this patch, set
CONFIG_DYNAMIC_DEBUG=y and boot with "acpiphp.dyndebug=+p" instead.
See Documentation/dynamic-debug-howto.txt.

[bhelgaas: changelog]
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Make PCI Host Bridge _OSC #defines more consistent.  No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_has_method() is a new ACPI API introduced to check
the existence of an ACPI control method.

It can be used to replace acpi_get_handle() in the case that
1. the calling function doesn't need the ACPI handle of the control method.
and
2. the calling function doesn't care the reason why the method is unavailable.

Convert acpi_get_handle() to acpi_has_method()
in drivers/pci/hotplug/acpi_pcihp.c in this patch.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
CC: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In the current ACPIPHP notify handler we always go directly for a
rescan of the parent bus if we get a device check notification for
a device that is not a bridge.  However, this obviously is
overzealous if nothing really changes, because this way we may rescan
the whole PCI hierarchy pretty much in vain.

That happens on Alex Williamson's machine whose ACPI tables contain
device objects that are supposed to coresspond to PCIe root ports,
but those ports aren't physically present (or at least they aren't
visible in the PCI config space to us).  The BIOS generates multiple
device check notifies for those objects during boot and for each of
them we go straight for the parent bus rescan, but the parent bus is
the root bus in this particular case.  In consequence, we rescan the
whole PCI bus from the top several times in a row, which is
completely unnecessary, increases boot time by 50% (after previous
fixes) and generates excess dmesg output from the PCI subsystem.

Fix the problem by checking if we can find anything new in the
slot corresponding to the device we've got a device check notify
for and doing nothig if that's not the case.

The spec (ACPI 5.0, Section 5.6.6) appears to mandate this behavior,
as it says:

  Device Check. Used to notify OSPM that the device either appeared
  or disappeared. If the device has appeared, OSPM will re-enumerate
  from the parent. If the device has disappeared, OSPM will
  invalidate the state of the device. OSPM may optimize out
  re-enumeration.

Therefore, according to the spec, we are free to do nothing if
nothing changes.

References: https://bugzilla.kernel.org/show_bug.cgi?id=60865Reported-and-tested-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The spec suggests that we should use _OST to notify the platform
about the status of notifications it sends us, for example so that
it doesn't repeate a notification that has been handled already.

This turns out to help reduce the amount of diagnostic output from
the ACPIPHP subsystem and speed up boot on at least one system that
generates multiple device check notifies for PCIe devices on the root
bus during boot.
Reported-and-tested-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Sometimes we may get a spurious device check or bus check notify for
a hotplug device and in those cases we should avoid doing all of the
configuration work needed when something actually changes.  To that
end, check the return value of pci_scan_slot() in enable_slot() and
bail out early if it is 0.

This turns out to help reduce the amount of diagnostic output from
the ACPIPHP subsystem and speed up boot on at least one system that
generates multiple device check notifies for PCIe devices on the root
bus during boot.
Reported-and-tested-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In acpiphp_bus_add() we first remove device objects corresponding to
the given handle and the ACPI namespace branch below it, which are
then re-created by acpi_bus_scan().  This used to be done to clean
up after surprise removals, but now we do the cleanup through
trim_stale_devices() which checks if the devices in question are
actually gone before removing them, so the device hierarchy trimming
in acpiphp_bus_add() is not necessary any more and, moreover, it may
lead to problems if it removes device objects corresponding to
devices that are actually present.

For this reason, remove the leftover acpiphp_bus_trim() from
acpiphp_bus_add().
Reported-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add an arch specific attribute to recover a pci function from an
error state or config space blockage.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Convert s390' pci hotplug to be builtin only, with no module option.
Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Based on a patch by Jon Mason (see URL below).

All users of pcie_bus_configure_settings() pass arguments of the form
"bus, bus->self->pcie_mpss".  The "mpss" argument is redundant since we
can easily look it up internally.  In addition, all callers check
"bus->self" for NULL, which we can also do internally.

This patch simplifies the interface and the callers.  No functional change.

Reference: http://lkml.kernel.org/r/1317048850-30728-2-git-send-email-mason@myri.comSigned-off-by: NBjorn Helgaas <bhelgaas@google.com>

After commit bbd34fcd (ACPI / hotplug / PCI: Register all devices
under the given bridge) register_slot() is called for all PCI
devices under a given bridge that have corresponding objects in
the ACPI namespace, but it calls acpiphp_register_hotplug_slot()
only for devices satisfying specific criteria.  Still,
cleanup_bridge() calls acpiphp_unregister_hotplug_slot() for all
objects created by register_slot(), although it should only call it
for the ones that acpiphp_register_hotplug_slot() has been called
for (successfully).  This causes a NULL pointer to be dereferenced
by the acpiphp_unregister_hotplug_slot() executed by cleanup_bridge()
if the object it is called for has not been passed to
acpiphp_register_hotplug_slot().

To fix this problem, check if the 'slot' field of the object passed
to acpiphp_unregister_hotplug_slot() in cleanup_bridge() is not NULL,
which only is the case if acpiphp_register_hotplug_slot() has been
executed for that object.  In addition to that, make register_slot()
reset the 'slot' field to NULL if acpiphp_register_hotplug_slot() has
failed for the given object to prevent stale pointers from being
used by acpiphp_unregister_hotplug_slot().
Reported-and-tested-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

PCIe hotplug has a bus per slot, so we can just use a normal
secondary bus reset.  However, if a slot supports surprise removal,
a bus reset can be seen as a presence detection change triggering
a hot-remove followed by a hot-add.  Disable presence detection from
triggering an interrupt or being polled around the bus reset.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Convert CONFIG_HOTPLUG_PCI from tristate to bool.  This only affects
the hotplug core; several of the hotplug drivers can still be modules.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

Hot-removing a device with SR-IOV enabled causes a null pointer dereference
in v3.9 and v3.10.

This is a regression caused by ba518e3c ("PCI: pciehp: Iterate over all
devices in slot, not functions 0-7").  When we iterate over the
bus->devices list, we first remove the PF, which also removes all the VFs
from the list.  Then the list iterator blows up because more than just the
current entry was removed from the list.

ac205b7b ("PCI: make sriov work with hotplug remove") works around a
similar problem in pci_stop_bus_devices() by iterating over the list in
reverse, so the VFs are stopped and removed from the list first, before the
PF.

This patch changes pciehp_unconfigure_device() to iterate over the list in
reverse, too.

[bhelgaas: bugzilla, changelog]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60604Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NYijing Wang <wangyijing@huawei.com>
CC: stable@vger.kernel.org	# v3.9+

We currently enable PCI bridges after scanning a bus and assigning
resources.  This is often done in arch code.

This patch changes this so we don't enable a bridge until necessary, i.e.,
until we enable a PCI device behind the bridge.  We do this in the generic
pci_enable_device() path, so this also removes the arch-specific code to
enable bridges.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>