gcc points out a type mismatch:
drivers/acpi/dock.c: In function 'hot_remove_dock_devices':
drivers/acpi/dock.c:234:53: warning: implicit conversion from 'enum <anonymous>' to 'enum dock_callback_type' [-Wenum-conversion]
234 | dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST, false);
This is harmless because 'false' still has the correct numeric value,
but passing DOCK_CALL_HANDLER documents better what is going on
and avoids the warning.
Fixes: 37f908778f ("ACPI / dock: Walk list in reverse order during removal of devices")
Fixes: f09ce741a0 ("ACPI / dock / PCI: Drop ACPI dock notifier chain")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The ACPICA debug ACPI_MODULE_NAME() definition is not used, remove it.
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Based on 3 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1105 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Functions working with attribute_groups provided by <linux/sysfs.h>
work with const attribute_group. These attribute_group structures do not
change at runtime so mark them as const.
File size before:
text data bss dec hex filename
7902 3528 64 11494 2ce6 drivers/acpi/dock.o
File size after:
text data bss dec hex filename
7998 3432 64 11494 2ce6 drivers/acpi/dock.o
This change was made with the help of Coccinelle.
Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The Kconfig for this file is:
drivers/acpi/Kconfig:config ACPI_DOCK
drivers/acpi/Kconfig: bool "Dock"
...and so it is not built as a module. Hence including module.h
and everything that comes with it just for the no-op MODULE_LICENSE
and friends is rather heavy handed.
The license/author info is found at the top of the file, so we
just remove the MODULE_LICENSE etc and the include of module.h
The file does still have some module_param() so we add the right
include for that infrastructure.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is no need to carry potentially outdated Free Software Foundation
mailing address in file headers since the COPYING file includes it.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now that we have struct fwnode_handle, we can use that to point to
ACPI companions from struct device objects instead of pointing to
struct acpi_device directly.
There are two benefits from that. First, the somewhat ugly and
hackish struct acpi_dev_node can be dropped and, second, the same
struct fwnode_handle pointer can be used in the future to point
to other (non-ACPI) firmware device node types.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
There are no references to the dock_device_ids[] table anywhere in
the code and it is not even useful for module autoloading, because
the dock driver can only be built in, so drop it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We already have a macro for PREFIX of "ACPI: " in
drivers/acpi/internal.h, so remove the duplicate ones
in ACPI drivers when internal.h is included.
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Update the copyright notice of the ACPI dock driver to reflect the
fact that substantial changes have been made to it recently.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since remove_dock_dependent_devices() is only called from acpi_dock_add()
and it only is called if the add_dock_dependent_device() adding the
dock station to its own list of dependent devices has failed, it is not
really necessary, because the dock station's list of dependent devices
is guaranteed to be empty at that point. Drop it, then.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since struct acpi_dock_ops and the code handling it don't have any
users any more after the previous changes, drop that structure and
the code related to it altogether.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In order to avoid the need to register special ACPI dock
operations for SATA devices add a .uevent() callback pointer to
struct acpi_hotplug_context and make dock_hotplug_event() use that
callback if available. Also rename the existing .event() callback
in struct acpi_hotplug_context to .notify() to avoid possible
confusion in the future.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Instead of requiring a set of special dock operations to be registered
via register_hotplug_dock_device() for each ACPI dock device, it is
much more straightforward to use callback pointers from the devices'
hotplug contexts if available.
For this reason, modify dock_hotplug_event() to use callback pointers
from the hotplug contexts of ACPI devices and fall back to using the
special dock operarions only if those callbacks are missing. Also
make the ACPI-based PCI hotplug (ACPIPHP) subsystem set the .fixup
callback pointer in the hotplug contexts of devices handled by it to
a new function, acpiphp_post_dock_fixup(), so that the dock station
driver can use the callbacks from those contexts instead of special
dock operations registered via register_hotplug_dock_device().
Along with the above changes drop the ACPIPHP's dock operations that
are not necessary any more.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Rework the ACPI dock station driver to store ACPI device object
pointers instead of ACPI handles in its internal data structures.
The purpose is moslty to make subsequent simplifications possible,
but also this allows the overall code size to be reduced slightly.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To allow user space to check which ACPI device object the dock
station is represented by, make acpi_dock_add() indicate to
platform_device_register_full() which ACPI device object should
be the companion of the new platform device.
This also ensures that the ACPI device object in question will
not go away while the dock platform device is present (which is
always).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since we already know what the device's PNP IDs are when
acpi_device_is_battery() is called, it is not necessary to run
acpi_get_object_info() for the device in that function. Instead, if
acpi_device_is_battery() is passed a pointer to a struct acpi_device
object, it can use the list of PNP IDs from that object, so make that
happen and modify the function's header accordingly
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The ACPI dock station code carries out an extra namespace scan
before the main one in order to find and register all of the dock
device objects. Then, it registers a notify handler for each of
them for handling dock events.
However, dock device objects need not be scanned for upfront. They
very well can be enumerated and registered during the first phase
of the main namespace scan, before attaching scan handlers and ACPI
drivers to ACPI device objects. Then, the dependent devices can be
added to the in the second phase. That makes it possible to drop
the extra namespace scan, so do it.
Moreover, it is not necessary to register notify handlers for all
of the dock stations' namespace nodes, becuase notifications may
be dispatched from the global notify handler for them. Do that and
drop two functions used for dock notify handling, acpi_dock_deferred_cb()
and dock_notify_handler(), that aren't necessary any more.
Finally, some dock station objects have _HID objects matching the
ACPI container scan handler which causes it to claim those objects
and try to handle their hotplug, but that is not a good idea,
because those objects have their own special hotplug handling anyway.
For this reason, the hotplug_notify flag should not be set for ACPI
device objects representing dock stations and the container scan
handler should be made ignore those objects, so make that happen.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After recent ACPI core changes acpi_bus_get_device() will always
succeed for dock station ACPI device objects, so show_docked()
should not use that function's return value as an indicator of
whether or not the dock device is present.
Make it use acpi_device_enumerated() for this purpose.
Fixes: 202317a573 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After commit 202317a573 (ACPI / scan: Add acpi_device objects for
all device nodes in the namespace) acpi_bus_get_device() will always
return 0 for dock devices in dock_notify(), so the dock station
docking code under ACPI_NOTIFY_DEVICE_CHECK will never be executed
and docking will not work as a result of that.
Fix the problem by making dock_notify() use acpi_device_enumerated()
to check the presence of the device instead of checking the return
value of acpi_bus_get_device().
Fixes: 202317a573 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Includes appropriate header file internal.h in dock.c because
function acpi_dock_init() has its prototype declaration in
internal.h.
This eliminates the following warning in dock.c:
drivers/acpi/dock.c:899:13: warning: no previous prototype for ‘acpi_dock_init’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
acpi_dock_init() is only called from acpi_scan_init() and the
code logic shows that it doesn't need to check acpi_disabled:
acpi_init();
if (acpi_disabled) return;
acpi_scan_init();
acpi_dock_init();
if (acpi_disabled) /* redundant */
return;
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.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: Lv 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: Rafael 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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
acpi_evaluate_integer() is an ACPI API introduced to evaluate an
ACPI control method that is known to have an integer return value.
This API can simplify the code because the calling function does not need to
use the specified acpi_buffer structure required by acpi_evaluate_object();
Convert acpi_evaluate_object() to acpi_evaluate_integer()
in drivers/acpi/dock.c in this patch.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
__init belongs after the return type on functions, not before it.
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix to return -ENODEV in the acpi notify handler install error
handling case instead of 0, as done elsewhere in this function.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The local variable id in dock_add() is not necessary, so drop it.
While we're at it, use an initializer to clear the local variable ds
and drop the memset() used for this purpose.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The only user of the ACPI dock notifier chain is the ACPI-based PCI
hotplug (acpiphp) driver that uses it to carry out post-dock fixups
needed by some systems with broken _DCK. However, it is not
necessary to use a separate notifier chain for that, as it can be
simply replaced with a new callback in struct acpi_dock_ops.
For this reason, add a new .fixup() callback to struct acpi_dock_ops
and make hotplug_dock_devices() execute it for all dock devices with
hotplug operations registered. Accordingly, make acpiphp point that
callback to the function carrying out the post-dock fixups and
do not register a separate dock notifier for each device
registering dock operations. Finally, drop the ACPI dock notifier
chain that has no more users.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The function creating and registering dock station objects,
dock_add(), leaks memory if there's an error after it's walked
the ACPI namespace calling find_dock_devices(), because it doesn't
free the list of dependent devices it's just created in those cases.
Fix that issue by adding the missing code to free the list of
dependent devices on errors.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The ACPI dock driver uses register_acpi_bus_notifier() which
installs a notifier triggered globally for all system notifications.
That first of all is inefficient, because the dock driver is only
interested in notifications associated with the devices it handles,
but it has to handle all system notifies for all devices. Moreover,
it does that even if no docking stations are present in the system
(CONFIG_ACPI_DOCK set is sufficient for that to happen). Besides,
that is inconvenient, because it requires the driver to do extra work
for each notification to find the target dock station object.
For these reasons, rework the dock driver to install a notify
handler individually for each dock station in the system using
acpi_install_notify_handler(). This allows the dock station
object to be passed directly to the notify handler and makes it
possible to simplify the dock driver quite a bit. It also
reduces the overhead related to the handling of all system
notifies when CONFIG_ACPI_DOCK is set.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Make dock_init_hotplug() and dock_release_hotplug() slightly simpler
and move some checks in those functions to the code paths where they
are needed.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
If there are indirect dependencies between devices in a dock
station's dependent devices list, they may be broken if the devices
are removed in the same order in which they have been added.
For this reason, make the code in handle_eject_request() walk the
list of dependent devices in reverse order.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Since acpi_walk_namespace() calls find_dock_devices() during tree
pre-order visit, the latter doesn't need to add devices whose
parents have _EJD pointing to the docking station to the list of
that station's dependent devices, because those parents are going to
be added to that list anyway and the removal of a parent will take
care of the removal of its children in those cases.
For this reason, rework find_dock_devices() to only call
add_dock_dependent_device() for devices whose _EJD point directy to
the docking station represented by its context argument and simplify
it slightly.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
The only existing user of the hp_lock mutex in struct dock_station,
hotplug_dock_devices(), is always called under acpi_scan_lock and
cannot race with another instance of itself, so drop the mutex
which is not necessary.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use helper functions introduced previously to simplify the ACPI dock
driver.
[rjw: Changelog]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The return value of dock_create_acpi_device() is not used at all,
so change its signature to return void and simplify the
implementation of it.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Mark all initialization functions with __init to reduce runtime
memory consumption.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
All dock station objects are created during initialization and
don't change at runtime, so drop the redundant spin lock from
struct dock_station.
[rjw: Changelog]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Function dock_add() will be called multiple times if there are
multiple dock stations, which causes acpi_dock_notifier_list to be
initialized multiple times.
To avoid that, move the initialization of acpi_dock_notifier_list
from dock_add() to acpi_dock_init().
[rjw: Changelog]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit 94add0f (ACPI / dock: Initialize ACPI dock subsystem upfront)
changed the header of acpi_dock_init() in internal.h so that it is
supposed to be a void function now, but it forgot to update its
actual definition in dock.c according to which it still is supposed
to return int.
Although that didn't cause any visible breakage or even a compiler
warning to be thrown, which is odd enough, fix it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.10+ <stable@vger.kernel.org>
The interactions between the ACPI dock driver and the ACPI-based PCI
hotplug (acpiphp) are currently problematic because of ordering
issues during hot-remove operations.
First of all, the current ACPI glue code expects that physical
devices will always be deleted before deleting the companion ACPI
device objects. Otherwise, acpi_unbind_one() will fail with a
warning message printed to the kernel log, for example:
[ 185.026073] usb usb5: Oops, 'acpi_handle' corrupt
[ 185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
[ 185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
[ 180.013656] port1: Oops, 'acpi_handle' corrupt
This means, in particular, that struct pci_dev objects have to
be deleted before the struct acpi_device objects they are "glued"
with.
Now, the following happens the during the undocking of an ACPI-based
dock station:
1) hotplug_dock_devices() invokes registered hotplug callbacks to
destroy physical devices associated with the ACPI device objects
depending on the dock station. It calls dd->ops->handler() for
each of those device objects.
2) For PCI devices dd->ops->handler() points to
handle_hotplug_event_func() that queues up a separate work item
to execute _handle_hotplug_event_func() for the given device and
returns immediately. That work item will be executed later.
3) hotplug_dock_devices() calls dock_remove_acpi_device() for each
device depending on the dock station. This runs acpi_bus_trim()
for each of them, which causes the underlying ACPI device object
to be destroyed, but the work items queued up by
handle_hotplug_event_func() haven't been started yet.
4) _handle_hotplug_event_func() queued up in step 2) are executed
and cause the above failure to happen, because the PCI devices
they handle do not have the companion ACPI device objects any
more (those objects have been deleted in step 3).
The possible breakage doesn't end here, though, because
hotplug_dock_devices() may return before at least some of the
_handle_hotplug_event_func() work items spawned by it have a
chance to complete and then undock() will cause _DCK to be
evaluated and that will cause the devices handled by the
_handle_hotplug_event_func() to go away possibly while they are
being accessed.
This means that dd->ops->handler() for PCI devices should not point
to handle_hotplug_event_func(). Instead, it should point to a
function that will do the work of _handle_hotplug_event_func()
synchronously. For this reason, introduce such a function,
hotplug_event_func(), and modity acpiphp_dock_ops to point to
it as the handler.
Unfortunately, however, this is not sufficient, because if the dock
code were not changed further, hotplug_event_func() would now
deadlock with hotplug_dock_devices() that called it, since it would
run unregister_hotplug_dock_device() which in turn would attempt to
acquire the dock station's hp_lock mutex already acquired by
hotplug_dock_devices().
To resolve that deadlock use the observation that
unregister_hotplug_dock_device() won't need to acquire hp_lock
if PCI bridges the devices on the dock station depend on are
prevented from being removed prematurely while the first loop in
hotplug_dock_devices() is in progress.
To make that possible, introduce a mechanism by which the callers of
register_hotplug_dock_device() can provide "init" and "release"
routines that will be executed, respectively, during the addition
and removal of the physical device object associated with the
given ACPI device handle. Make acpiphp use two new functions,
acpiphp_dock_init() and acpiphp_dock_release(), that call
get_bridge() and put_bridge(), respectively, on the acpiphp bridge
holding the given device, for this purpose.
In addition to that, remove the dock station's list of
"hotplug devices" and make the dock code always walk the whole list
of "dependent devices" instead in such a way that the loops in
hotplug_dock_devices() and dock_event() (replacing the loops over
"hotplug devices") will take references to the list entries that
register_hotplug_dock_device() has been called for. That prevents
the "release" routines associated with those entries from being
called while the given entry is being processed and for PCI
devices this means that their bridges won't be removed (by a
concurrent thread) while hotplug_event_func() handling them is
being executed.
This change is based on two earlier patches from Jiang Liu.
References: https://bugzilla.kernel.org/show_bug.cgi?id=59501
Reported-and-tested-by: Alexander E. Patrakov <patrakov@gmail.com>
Tracked-down-by: Jiang Liu <jiang.liu@huawei.com>
Tested-by: Illya Klymov <xanf@xanf.me>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org>
