PCI: Remove MODULE_LICENSE so boolean drivers don't look like modules

Since 8b41fc4454e3 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations

PCI: Remove MODULE_LICENSE so boolean drivers don't look like modules

Since 8b41fc4454e3 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations are
used to identify modules. As a consequence, MODULE_LICENSE in non-modules
causes modprobe to misidentify the object file as a module when it is not,
and modprobe might succeed rather than failing with a suitable error
message.

For tristate modules that can be either built-in or loaded at runtime,
modprobe succeeds in both cases:

# modprobe ext4
[exit status zero if CONFIG_EXT4_FS=y or =m]

For boolean modules like the Standard Hot Plug Controller driver (shpchp)
that cannot be loaded at runtime, modprobe should always fail like this:

# modprobe shpchp
modprobe: FATAL: Module shpchp not found in directory /lib/modules/...
[exit status non-zero regardless of CONFIG_HOTPLUG_PCI_SHPC]

but prior to this commit, shpchp_core.c contained MODULE_LICENSE, so
"modprobe shpchp" silently succeeded when it should have failed.

Remove MODULE_LICENSE in files that cannot be built as modules.

[bhelgaas: commit log, squash]
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230216152410.4312-1-nick.alcock@oracle.com/
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>

show more ...

PCI: Add defines for normal and subtractive PCI bridges

Add these PCI class codes to pci_ids.h:

PCI_CLASS_BRIDGE_PCI_NORMAL
PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE

Use these defines in all kernel cod

PCI: Add defines for normal and subtractive PCI bridges

Add these PCI class codes to pci_ids.h:

PCI_CLASS_BRIDGE_PCI_NORMAL
PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE

Use these defines in all kernel code for describing PCI class codes for
normal and subtractive PCI bridges.

[bhelgaas: similar change in pci-mvebu.c]
Link: https://lore.kernel.org/r/20220214114109.26809-1-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: hotplug: Embed hotplug_slot

When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its inte

PCI: hotplug: Embed hotplug_slot

When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of(). But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths. Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference. And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct. The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com> # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>

show more ...

PCI: hotplug: Drop hotplug_slot_info

Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tg

PCI: hotplug: Drop hotplug_slot_info

Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Apparently the idea was that drivers furnish the hotplug core with an
up-to-date card presence status, power status, latch status and
attention indicator status as well as notify the hotplug core of changes
thereof. However only 4 out of 12 hotplug drivers bother to notify the
hotplug core with pci_hp_change_slot_info() and the hotplug core never
made any use of the information: There is just a single macro in
pci_hotplug_core.c, GET_STATUS(), which uses the hotplug_slot_info if
the driver lacks the corresponding callback in hotplug_slot_ops. The
macro is called when the user reads the attribute via sysfs.

Now, if the callback isn't defined, the attribute isn't exposed in sysfs
in the first place (see e.g. has_power_file()). There are only two
situations when the hotplug_slot_info would actually be accessed:

* If the driver defines ->enable_slot or ->disable_slot but not
->get_power_status.

* If the driver defines ->set_attention_status but not
->get_attention_status.

There is no driver doing the former and just a single driver doing the
latter, namely pnv_php.c. Amend it with a ->get_attention_status
callback. With that, the hotplug_slot_info becomes completely unused by
the PCI hotplug core. But a few drivers use it internally as a cache:

cpcihp uses it to cache the latch_status and adapter_status.
cpqhp uses it to cache the adapter_status.
pnv_php and rpaphp use it to cache the attention_status.
shpchp uses it to cache all four values.

Amend these drivers to cache the information in their private slot
struct. shpchp's slot struct already contains members to cache the
power_status and adapter_status, so additional members are only needed
for the other two values. In the case of cpqphp, the cached value is
only accessed in a single place, so instead of caching it, read the
current value from the hardware.

Caution: acpiphp, cpci, cpqhp, shpchp, asus-wmi and eeepc-laptop
populate the hotplug_slot_info with initial values on probe. That code
is herewith removed. There is a theoretical chance that the code has
side effects without which the driver fails to function, e.g. if the
ACPI method to read the adapter status needs to be executed at least
once on probe. That seems unlikely to me, still maintainers should
review the changes carefully for this possibility.

Rafael adds: "I'm not aware of any case in which it will break anything,
[...] but if that happens, it may be necessary to add the execution of
the control methods in question directly to the initialization part."

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com> # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>

show more ...

PCI: hotplug: Constify hotplug_slot_ops

Hotplug drivers cannot declare their hotplug_slot_ops const, making them
attractive targets for attackers, because upon registration of a hotplug
slot, __pci_

PCI: hotplug: Constify hotplug_slot_ops

Hotplug drivers cannot declare their hotplug_slot_ops const, making them
attractive targets for attackers, because upon registration of a hotplug
slot, __pci_hp_initialize() writes to the "owner" and "mod_name" members
in that struct.

Fix by moving these members to struct hotplug_slot and constify every
driver's hotplug_slot_ops except for pciehp.

pciehp constructs its hotplug_slot_ops at runtime based on the PCIe
port's capabilities, hence cannot declare them const. It can be
converted to __write_rarely once that's mainlined:
http://www.openwall.com/lists/kernel-hardening/2016/11/16/3

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>

show more ...

PCI: hotplug: Demidlayer registration with the core

When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and

PCI: hotplug: Demidlayer registration with the core

When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and addition to sysfs. That's a problem for pciehp once it's converted
to enable/disable the slot exclusively from the IRQ thread: The thread
needs to be spawned after creation of the kobject (because it uses the
kobject's name), but before addition to sysfs (because it will handle
enable/disable requests submitted via sysfs).

pci_hp_deregister() does offer a ->release callback that's invoked
after deletion from sysfs and before destruction of the kobject. But
because pci_hp_register() doesn't offer a counterpart, hotplug drivers'
->probe and ->remove code becomes asymmetric, which is error prone
as recently discovered use-after-free bugs in pciehp's ->remove hook
have shown.

In a sense, this appears to be a case of the midlayer antipattern:

"The core thesis of the "midlayer mistake" is that midlayers are
bad and should not exist. That common functionality which it is
so tempting to put in a midlayer should instead be provided as
library routines which can [be] used, augmented, or ignored by
each bottom level driver independently. Thus every subsystem
that supports multiple implementations (or drivers) should
provide a very thin top layer which calls directly into the
bottom layer drivers, and a rich library of support code that
eases the implementation of those drivers. This library is
available to, but not forced upon, those drivers."
-- Neil Brown (2009), https://lwn.net/Articles/336262/

The presence of midlayer traits in the PCI hotplug core might be ascribed
to its age: When it was introduced in February 2002, the blessings of a
library approach might not have been well known:
https://git.kernel.org/tglx/history/c/a8a2069f432c

For comparison, the driver core does offer split functions for creating
a kobject (device_initialize()) and addition to sysfs (device_add()) as
an alternative to carrying out everything at once (device_register()).
This was introduced in October 2002:
https://git.kernel.org/tglx/history/c/8b290eb19962

The odd ->release callback in the PCI hotplug core was added in 2003:
https://git.kernel.org/tglx/history/c/69f8d663b595

Clearly, a library approach would not force every hotplug driver to
implement a ->release callback, but rather allow the driver to remove
the sysfs files, release its data structures and finally destroy the
kobject. Alternatively, a driver may choose to remove everything with
pci_hp_deregister(), then release its data structures.

To this end, offer drivers pci_hp_initialize() and pci_hp_add() as a
split-up version of pci_hp_register(). Likewise, offer pci_hp_del()
and pci_hp_destroy() as a split-up version of pci_hp_deregister().

Eliminate the ->release callback and move its code into each driver's
teardown routine.

Declare pci_hp_deregister() void, in keeping with the usual kernel
pattern that enablement can fail, but disablement cannot. It only
returned an error if the caller passed in a NULL pointer or a slot which
has never or is no longer registered or is sharing its name with another
slot. Those would be bugs, so WARN about them. Few hotplug drivers
actually checked the return value and those that did only printed a
useless error message to dmesg. Remove that.

For most drivers the conversion was straightforward since it doesn't
matter whether the code in the ->release callback is executed before or
after destruction of the kobject. But in the case of ibmphp, it was
unclear to me whether setting slot_cur->ctrl and slot_cur->bus_on to
NULL needs to happen before the kobject is destroyed, so I erred on
the side of caution and ensured that the order stays the same. Another
nontrivial case is pnv_php, I've found the list and kref logic difficult
to understand, however my impression was that it is safe to delete the
list element and drop the references until after the kobject is
destroyed.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Andy Shevchenko <andy@infradead.org>

show more ...

PCI: shpchp: Separate existence of SHPC and permission to use it

The shpchp driver registers for all PCI bridge devices. Its probe method
should fail if either (1) the bridge doesn't have an SHPC o

PCI: shpchp: Separate existence of SHPC and permission to use it

The shpchp driver registers for all PCI bridge devices. Its probe method
should fail if either (1) the bridge doesn't have an SHPC or (2) the OS
isn't allowed to use it (the platform firmware may be operating the SHPC
itself).

Separate these two tests into:

- A new shpc_capable() that looks for the SHPC hardware and is applicable
on all systems (ACPI and non-ACPI), and

- A simplified acpi_get_hp_hw_control_from_firmware() that we call only
when we already know an SHPC exists and there may be ACPI methods to
either request permission to use it (_OSC) or transfer control to the
OS (OSHP).

acpi_get_hp_hw_control_from_firmware() is implemented when CONFIG_ACPI=y,
but does nothing if the current platform doesn't support ACPI.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

PCI: shpchp: Add shpchp_is_native()

In the same way we do for pciehp, add shpchp_is_native(), which returns
true if the bridge should be handled by the native SHPC driver. Then
convert the driver t

PCI: shpchp: Add shpchp_is_native()

In the same way we do for pciehp, add shpchp_is_native(), which returns
true if the bridge should be handled by the native SHPC driver. Then
convert the driver to use this function.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: shpchp: Remove get_hp_hw_control_from_firmware() wrapper

get_hp_hw_control_from_firmware() is a trivial wrapper around
acpi_get_hp_hw_control_from_firmware(), probably intended to be generic in

PCI: shpchp: Remove get_hp_hw_control_from_firmware() wrapper

get_hp_hw_control_from_firmware() is a trivial wrapper around
acpi_get_hp_hw_control_from_firmware(), probably intended to be generic in
case other firmware needed similar OS/platform negotiation.

Remove get_hp_hw_control_from_firmware() and call
acpi_get_hp_hw_control_from_firmware() directly. Add a stub for
acpi_get_hp_hw_control_from_firmware() for the non-ACPI case.

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

show more ...

PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate

Add SPDX GPL-2.0+ to all PCI files that specified the GPL and allowed
either GPL version 2 or any later version.

Remove the boilerplate

PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate

Add SPDX GPL-2.0+ to all PCI files that specified the GPL and allowed
either GPL version 2 or any later version.

Remove the boilerplate GPL version 2 or later language, relying on the
assertion in b24413180f56 ("License cleanup: add SPDX GPL-2.0 license
identifier to files with no license") that the SPDX identifier may be used
instead of the full boilerplate text.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

PCI: Remove unnecessary messages for memory allocation failures

Per ebfdc40969f2 ("checkpatch: attempt to find unnecessary 'out of memory'
messages"), when a memory allocation fails, the memory subs

PCI: Remove unnecessary messages for memory allocation failures

Per ebfdc40969f2 ("checkpatch: attempt to find unnecessary 'out of memory'
messages"), when a memory allocation fails, the memory subsystem emits
generic "out of memory" messages (see slab_out_of_memory() for some of this
logging). Therefore, additional error messages in the caller don't add
much value.

Remove messages that merely report "out of memory".

This preserves some messages that report additional information, e.g.,
allocation failures that mean we drop hotplug events.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[bhelgaas: changelog, squash patches, make similar changes to acpiphp,
cpqphp, ibmphp, keep warning when dropping hotplug event]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: Constify hotplug pci_device_id structures

pci_device_id are not supposed to change at runtime. All functions working
with pci_device_id provided by <linux/pci.h> work with const pci_device_id.

PCI: Constify hotplug pci_device_id structures

pci_device_id are not supposed to change at runtime. All functions working
with pci_device_id provided by <linux/pci.h> work with const pci_device_id.
So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
[bhelgaas: squash shpchp, ibmphp, bmphp_ebda, cpcihp_zt5550, cpqphp]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: hotplug: Use list_for_each_entry() to simplify code

Use list_for_each_entry() instead of list_for_each() to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by:

PCI: hotplug: Use list_for_each_entry() to simplify code

Use list_for_each_entry() instead of list_for_each() to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: Fix all whitespace issues

Fix all whitespace issues (missing or needed whitespace) in all files in
drivers/pci. Code is compiled with allyesconfig before and after code
changes and objects are

PCI: Fix all whitespace issues

Fix all whitespace issues (missing or needed whitespace) in all files in
drivers/pci. Code is compiled with allyesconfig before and after code
changes and objects are recorded and checked with objdiff and they are not
changed after this commit.

Signed-off-by: Bogicevic Sasa <brutallesale@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

PCI: Merge multi-line quoted strings

Merge quoted strings that are broken across lines into a single entity.
The compiler merges them anyway, but checkpatch complains about it, and
merging them make

PCI: Merge multi-line quoted strings

Merge quoted strings that are broken across lines into a single entity.
The compiler merges them anyway, but checkpatch complains about it, and
merging them makes it easier to grep for strings.

No functional change.

[bhelgaas: changelog, do the same for everything under drivers/pci]
Signed-off-by: Ryan Desfosses <ryan@desfo.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

show more ...

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>

show more ...

drivers: avoid format strings in names passed to alloc_workqueue()

For the workqueue creation interfaces that do not expect format strings,
make sure they cannot accidently be parsed that way. Addi

drivers: avoid format strings in names passed to alloc_workqueue()

For the workqueue creation interfaces that do not expect format strings,
make sure they cannot accidently be parsed that way. Additionally, clean
up calls made with a single parameter that would be handled as a format
string. Many callers are passing potentially dynamic string content, so
use "%s" in those cases to avoid any potential accidents.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

PCI: shpchp: Use per-slot workqueues to avoid deadlock

When we have an SHPC-capable bridge with a second SHPC-capable bridge
below it, pushing the upstream bridge's attention button causes a
deadloc

PCI: shpchp: Use per-slot workqueues to avoid deadlock

When we have an SHPC-capable bridge with a second SHPC-capable bridge
below it, pushing the upstream bridge's attention button causes a
deadlock.

The deadlock happens because we use the shpchp_wq workqueue to run
shpchp_pushbutton_thread(), which uses shpchp_disable_slot() to remove
devices below the upstream bridge. When we remove the downstream bridge,
we call shpc_remove(), the shpchp driver's .remove() method. That calls
flush_workqueue(shpchp_wq), which deadlocks because the
shpchp_pushbutton_thread() work item is still running.

This patch avoids the deadlock by creating a workqueue for every slot
and removing the single shared workqueue.

Here's the call path that leads to the deadlock:

shpchp_queue_pushbutton_work
queue_work(shpchp_wq) # shpchp_pushbutton_thread
...

shpchp_pushbutton_thread
shpchp_disable_slot
remove_board
shpchp_unconfigure_device
pci_stop_and_remove_bus_device
...
shpc_remove # shpchp driver .remove method
hpc_release_ctlr
cleanup_slots
flush_workqueue(shpchp_wq)

This change is based on code inspection, since we don't have hardware
with this topology.

Based-on-patch-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org

show more ...

PCI: shpchp: Handle push button event asynchronously

Use non-ordered workqueue for attention button events.

Attention button events on each slot can be handled asynchronously. So
we should use non-

PCI: shpchp: Handle push button event asynchronously

Use non-ordered workqueue for attention button events.

Attention button events on each slot can be handled asynchronously. So
we should use non-ordered workqueue. This patch also removes ordered
workqueue in shpchp as a result.

486b10b9f4 ("PCI: pciehp: Handle push button event asynchronously") made
the same change to pciehp. I split this out from a patch by Yijing Wang
<wangyijing@huawei.com> so we fix one thing at a time and to make the
shpchp history correspond more closely with the pciehp history.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

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PCI: shpchp: Make shpchp_wq non-ordered

e24dcbef93 ("shpchp: update workqueue usage") was described as adding
non-ordered shpchp_wq, but it actually made it an *ordered* workqueue.

This patch chang

PCI: shpchp: Make shpchp_wq non-ordered

e24dcbef93 ("shpchp: update workqueue usage") was described as adding
non-ordered shpchp_wq, but it actually made it an *ordered* workqueue.

This patch changes shpchp_wq to be non-ordered, as described in the
e24dcbef93 commit log and as was done for pciehp by a827ea307b ("pciehp:
update workqueue usage").

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>

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PCI: hotplug: ensure a consistent return value in error case

Typically, the return value desired for the failure of a function with an
integer return value is a negative integer. In these cases, th

PCI: hotplug: ensure a consistent return value in error case

Typically, the return value desired for the failure of a function with an
integer return value is a negative integer. In these cases, the return
value is sometimes a negative integer and sometimes 0, due to a subsequent
initialization of the return variable within the loop.

A simplified version of the semantic match that finds this problem is:
(http://coccinelle.lip6.fr/)

//<smpl>
@r exists@
identifier ret;
position p;
constant C;
expression e1,e3,e4;
statement S;
@@

ret = -C
... when != ret = e3
when any
if@p (...) S
... when any
if (\(ret != 0\|ret < 0\|ret > 0\) || ...) { ... return ...; }
... when != ret = e3
when any
*if@p (...)
{
... when != ret = e4
return ret;
}
//</smpl>

[bhelgaas: squashed into one patch]
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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module_param: make bool parameters really bool (drivers & misc)

module_param(bool) used to counter-intuitively take an int. In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy

module_param: make bool parameters really bool (drivers & misc)

module_param(bool) used to counter-intuitively take an int. In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option. For this version
it'll simply give a warning, but it'll break next kernel version.

Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

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PCI hotplug: shpchp: don't blindly claim non-AMD 0x7450 device IDs

Previously we claimed device ID 0x7450, regardless of the vendor, which is
clearly wrong. Now we'll claim that device ID only for

PCI hotplug: shpchp: don't blindly claim non-AMD 0x7450 device IDs

Previously we claimed device ID 0x7450, regardless of the vendor, which is
clearly wrong. Now we'll claim that device ID only for AMD.

I suspect this was just a typo in the original code, but it's possible this
change will break shpchp on non-7450 AMD bridges. If so, we'll have to fix
them as we find them.

Reference: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=638863
Reported-by: Ralf Jung <ralfjung-e@gmx.de>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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shpchp: update workqueue usage

* Rename shpchp_wq to shpchp_ordered_wq and add non-ordered shpchp_wq
which is used instead of the system workqueue. This is to remove
the use of flush_scheduled_

shpchp: update workqueue usage

* Rename shpchp_wq to shpchp_ordered_wq and add non-ordered shpchp_wq
which is used instead of the system workqueue. This is to remove
the use of flush_scheduled_work() which is deprecated and scheduled
for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
Create both shpchp_wq and shpchp_ordered_wq upfront.

* Include workqueue.h from shpchp.h.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when bu

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

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