Several core ACPI device drivers set acpi_device_class() for the given
struct acpi_device to whatever they like, but that value is never used
unless the driver itself uses it and, sadly, they neglect to clear it on
remove.  Since the only one of them still using acpi_device_class()
after previous changes is the button driver, update the others to stop
setting it in vain.  Also drop the related device class sybmols that
become redundant.

Since the ACPI button driver continues to use acpi_device_class(), make
it clear the struct field represented by acpi_device_class() in its
remove callback.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/3706295.iIbC2pHGDl@rafael.j.wysocki

Update several core ACPI device drivers that use
acpi_bus_generate_netlink_event() for generating netlink messages to
pass a string literal as its first argument instead of a pointer to
pnp.device_class in a given struct acpi_device, which will allow them
to avoid initializing the pnp.device_class field in the future.

The ACPI button driver that uses different acpi_device_class()
values for different button types will still pass it to
acpi_bus_generate_netlink_event(), but update it to use the
acpi_device_class() macro instead of open coding the pointer
access path.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/7944022.EvYhyI6sBW@rafael.j.wysocki

ACPI drivers usually set acpi_device_name() for the given struct
acpi_device to whatever they like, but that value is never used unless
the driver itself uses it and, quite unfortunately, drivers neglect to
clear it on remove.  Some drivers use it for printing messages or
initializing the names of subordinate devices, but it is better to use
string literals for that, especially if the given one is used just once.

To eliminate unnecessary overhead related to acpi_device_name()
handling, rework multiple core ACPI device drivers to stop setting
acpi_device_name() for struct acpi_device objects manipulated
by them and use a string literal instead of it where applicable.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/10840483.nUPlyArG6x@rafael.j.wysocki

This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>

Modify acpi_button_remove() to get the ACPI device object pointer
from button->adev instead of retrieving it with the help of the
ACPI_COMPANION() macro to reduce overhead slightly.

While at it, rename the struct acpi_device pointer variable in
acpi_button_remove() to adev.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/13948466.uLZWGnKmhe@rafael.j.wysocki

Modify struct acpi_button to hold a struct device pointer instead
of a struct platform_device one to avoid unnecessary pointer
dereferences and use that pointer consistently for system wakeup
initialization, handling and cleanup.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/1948258.tdWV9SEqCh@rafael.j.wysocki

Calling device_init_wakeup() after installing a notify handler in which
wakeup events are signaled may cause a wakeup event to be missed if the
device is probed right before a system suspend.

To avoid this, move the device_init_wakeup() call in acpi_button_probe()
before the notify handler installation and add a corresponding cleanup
to the error path.

Also carry out wakeup cleanup for the button in acpi_button_remove()
because after that point the notify handler will not run for it and
wakeup events coming from it will not be signaled.

Fixes: 0d51157dfaac ("ACPI: button: Eliminate the driver notify callback")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/12854922.O9o76ZdvQC@rafael.j.wysocki

While binding drivers directly to struct acpi_device objects allows
basic functionality to be provided, at least in the majority of cases,
there are some problems with it, related to general consistency, sysfs
layout, power management operation ordering, and code cleanliness.

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ACPI button driver to a platform one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2461734.NG923GbCHz@rafael.j.wysocki

Adjust the event notification routines in the ACPI button driver to
take a struct acpi_button pointer as an argument istead of a struct
acpi_device one where applicable, which allows the use of
acpi_driver_data() to be limited and will facilitate subsequent
changes.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2260995.Icojqenx9y@rafael.j.wysocki