PCI: Fix whitespace, capitalization, and spelling errors

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

PCI: Fix whitespace, capitalization, and spelling errors

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: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routines

There are two different interfaces for queuing up work items on the
ACPI hotplug workqueue, alloc_acpi_hp_work() used by PCI a

ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routines

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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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Revert "ACPI / hotplug / PCI: Avoid doing too much for spurious notifies"

Commit 2dc4128 (ACPI / hotplug / PCI: Avoid doing too much for
spurious notifies) changed the enable_slot() to check return

Revert "ACPI / hotplug / PCI: Avoid doing too much for spurious notifies"

Commit 2dc4128 (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
a47d8c8 (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: 2dc41281b1d1 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies)
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Drop WARN_ON() from acpiphp_enumerate_slots()

The WARN_ON() in acpiphp_enumerate_slots() triggers unnecessarily for
devices whose bridges are going to be handled by native PCIe

ACPI / hotplug / PCI: Drop WARN_ON() from acpiphp_enumerate_slots()

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=62831
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Fix error code path in acpiphp_enumerate_slots()

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

ACPI / hotplug / PCI: Fix error code path in acpiphp_enumerate_slots()

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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

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PCI: acpiphp: Convert to dynamic debug

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

PCI: acpiphp: Convert to dynamic debug

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: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks

In the current ACPIPHP notify handler we always go directly for a
rescan of the parent bus if we get a device check notificat

ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks

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=60865
Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Use _OST to notify firmware about notify status

The spec suggests that we should use _OST to notify the platform
about the status of notifications it sends us, for example so t

ACPI / hotplug / PCI: Use _OST to notify firmware about notify status

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: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Avoid doing too much for spurious notifies

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

ACPI / hotplug / PCI: Avoid doing too much for spurious notifies

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: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Don't trim devices before scanning the namespace

In acpiphp_bus_add() we first remove device objects corresponding to
the given handle and the ACPI namespace branch below it, w

ACPI / hotplug / PCI: Don't trim devices before scanning the namespace

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: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Fix NULL pointer dereference in cleanup_bridge()

After commit bbd34fc (ACPI / hotplug / PCI: Register all devices
under the given bridge) register_slot() is called for all PCI

ACPI / hotplug / PCI: Fix NULL pointer dereference in cleanup_bridge()

After commit bbd34fc (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: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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PCI: Delay enabling bridges until they're needed

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

PCI: Delay enabling bridges until they're needed

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: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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ACPI / hotplug / PCI: Get rid of check_sub_bridges()

Now that acpiphp_check_bridge() always enumerates devices behind the
bridge, there is no need to do that for each sub-bridge anymore like
it is d

ACPI / hotplug / PCI: Get rid of check_sub_bridges()

Now that acpiphp_check_bridge() always enumerates devices behind the
bridge, there is no need to do that for each sub-bridge anymore like
it is done in the current ACPI-based PCI hotplug (ACPIPHP) code.

Given this we don't need check_sub_bridges() anymore, so drop that
function completely.

This also simplifies the ACPIPHP code a bit.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Clean up bridge_mutex usage

Do not acquire bridge_mutex around the addition of a slot to its
bridge's list of slots and arount the addition of a function to
its slot's list of

ACPI / hotplug / PCI: Clean up bridge_mutex usage

Do not acquire bridge_mutex around the addition of a slot to its
bridge's list of slots and arount the addition of a function to
its slot's list of functions, because that doesn't help anything
right now (those lists are walked without any locking anyway).

However, acquire bridge_mutex around the list walk in
acpiphp_remove_slots() and use list_for_each_entry() there,
because we terminate the walk as soon as we find the first matching
entry. This prevents that list walk from colliding with bridge
addition and removal.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Redefine enable_device() and disable_device()

Notice that functions enable_device() and disable_device() cannot
fail and their return values are ignored in the majority of plac

ACPI / hotplug / PCI: Redefine enable_device() and disable_device()

Notice that functions enable_device() and disable_device() cannot
fail and their return values are ignored in the majority of places,
so redefine them as void and use the opportunity to change their
names to enable_slot() and disable_slot(), respectively, which much
better reflects what they do.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Sanitize acpiphp_get_(latch)|(adapter)_status()

There is no need for a temporary variable and all the tricks with
ternary operators in acpiphp_get_(latch)|(adapter)_status(). C

ACPI / hotplug / PCI: Sanitize acpiphp_get_(latch)|(adapter)_status()

There is no need for a temporary variable and all the tricks with
ternary operators in acpiphp_get_(latch)|(adapter)_status(). Change
those functions to be a bit more straightforward.

[rjw: Changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Check for new devices on enabled slots

The current implementation of acpiphp_check_bridge() is pretty dumb:
- It enables a slot if it's not enabled and the slot status is
A

ACPI / hotplug / PCI: Check for new devices on enabled slots

The current implementation of acpiphp_check_bridge() is pretty dumb:
- It enables a slot if it's not enabled and the slot status is
ACPI_STA_ALL.
- It disables a slot if it's enabled and the slot status is not
ACPI_STA_ALL.

This behavior is not sufficient to handle the Thunderbolt daisy
chaining case properly, however, because in that case the bus
behind the already enabled slot needs to be rescanned for new
devices.

For this reason, modify acpiphp_check_bridge() so that slots are
disabled and stopped if they are not in the ACPI_STA_ALL state.

For slots in the ACPI_STA_ALL state, devices behind them that don't
respond are trimmed using a new function, trim_stale_devices(),
introduced specifically for this purpose. That function walks
the given bus and checks each device on it. If the device doesn't
respond, it is assumed to be gone and is removed.

Once all of the stale devices directy behind the slot have been
removed, acpiphp_check_bridge() will start looking for new devices
that might have appeared on the given bus. It will do that even if
the slot is already enabled (SLOT_ENABLED is set for it).

In addition to that, make the bus check notification ignore
SLOT_ENABLED and go for enable_device() directly if bridge is NULL,
so that devices behind the slot are re-enumerated in that case too.

This change is based on earlier patches from Kirill A Shutemov
and Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Allow slots without new devices to be rescanned

Currently, enable_device() checks the return value of pci_scan_slot()
and returns immediately if that's 0 (meaning that no new f

ACPI / hotplug / PCI: Allow slots without new devices to be rescanned

Currently, enable_device() checks the return value of pci_scan_slot()
and returns immediately if that's 0 (meaning that no new functions
have been found in the slot). However, if one of the functions in
the slot is a bridge, some new devices may appear below it even if
the bridge itself is present continuously, so it generally is
necessary to do the rescan anyway just in case. [In particular,
that's necessary with the Thunderbolt daisy chaining in which case
new devices may be connected to the existing ones down the chain.]

The correctness of this change relies on the ability of
pcibios_resource_survey_bus() to detect if it has already been called
for the given bus and to skip it if so. Failure to do that will lead
to resource allocation conflicts.

[rjw: Changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Do not check SLOT_ENABLED in enable_device()

With Thunderbolt you can daisy chain devices: connect new devices to
an already plugged one. In that case the "hotplug slot" is al

ACPI / hotplug / PCI: Do not check SLOT_ENABLED in enable_device()

With Thunderbolt you can daisy chain devices: connect new devices to
an already plugged one. In that case the "hotplug slot" is already
enabled, but we still want to look for new PCI devices behind it.

Reuse enable_device() to scan for new PCI devices on enabled slots
and push the SLOT_ENABLED check up into acpiphp_enable_slot().

[rjw: Rebased, modified the changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Do not exectute _PS0 and _PS3 directly

The ACPI-based PCI hotplug (acpiphp) core code need not and really
should not execute _PS0 and _PS3 directly for devices it handles.

Fir

ACPI / hotplug / PCI: Do not exectute _PS0 and _PS3 directly

The ACPI-based PCI hotplug (acpiphp) core code need not and really
should not execute _PS0 and _PS3 directly for devices it handles.

First of all, it is not necessary to put devices into D3 after
acpi_bus_trim() has walked through them, because
acpi_device_unregister() invoked by it puts each device into D3cold
before returning. Thus after disable_device() the slot should be
powered down already.

Second, calling _PS0 directly on ACPI device objects may not be
appropriate, because it may require power resources to be set up in
a specific way in advance and that must be taken care of by the ACPI
core. Thus modify acpiphp_bus_add() to power up the device using
the appropriate interface after it has run acpi_bus_scan() on its
handle.

After that, the functions executing _PS0 and _PS3, power_on_slot()
and power_off_slot(), are not necessary any more, so drop them
and update the code calling them accordingly. Also drop the
function flags related to device power states, since they aren't
useful any more too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Do not queue up event handling work items in vain

Modify handle_hotplug_event() to avoid queing up the execution of
handle_hotplug_event_work_fn() as a work item on kacpi_hotpl

ACPI / hotplug / PCI: Do not queue up event handling work items in vain

Modify handle_hotplug_event() to avoid queing up the execution of
handle_hotplug_event_work_fn() as a work item on kacpi_hotplug_wq
for non-hotplug events, such as ACPI_NOTIFY_DEVICE_WAKE. Move
the code printing diagnostic messages for those events into
handle_hotplug_event().

In addition to that, remove the bogus comment about how the core
should distinguish between hotplug and non-hotplug events and
queue them up on different workqueues. The core clearly cannot
know in advance what events will be interesting to the given
caller of acpi_install_notify_handler().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Consolidate slot disabling and ejecting

Both acpiphp_disable_slot() and acpiphp_eject_slot() are always
called together so instead of calling each separately we can
consolidate

ACPI / hotplug / PCI: Consolidate slot disabling and ejecting

Both acpiphp_disable_slot() and acpiphp_eject_slot() are always
called together so instead of calling each separately we can
consolidate them into one function acpiphp_disable_and_eject_slot()
that does both (but it will return success on _EJ0 failures that
were ignored in the majority of call sites anyway).

[rjw: Rebased plus minor tweaks]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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ACPI / hotplug / PCI: Drop redundant checks from check_hotplug_bridge()

Two checks in check_hotplug_bridge() are redundant (they have been
done by the caller already), so drop them.

Signed-off-by:

ACPI / hotplug / PCI: Drop redundant checks from check_hotplug_bridge()

Two checks in check_hotplug_bridge() are redundant (they have been
done by the caller already), so drop them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Rework namespace scanning and trimming routines

The acpiphp_bus_trim() and acpiphp_bus_add() functions need not
return error codes that are never checked, so redefine them and

ACPI / hotplug / PCI: Rework namespace scanning and trimming routines

The acpiphp_bus_trim() and acpiphp_bus_add() functions need not
return error codes that are never checked, so redefine them and
simplify them a bit.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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ACPI / hotplug / PCI: Store parent in functions and bus in slots

To avoid chasing more pointers than necessary in some situations,
move the bridge pointer from struct acpiphp_slot to struct
acpiphp_

ACPI / hotplug / PCI: Store parent in functions and bus in slots

To avoid chasing more pointers than necessary in some situations,
move the bridge pointer from struct acpiphp_slot to struct
acpiphp_func (and call it 'parent') and add a bus pointer to
struct acpiphp_slot.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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