linux-toradex.git/drivers/acpi/dock.c, branch v3.9-rc3

ACPI / hotplug: Fix concurrency issues and memory leaks

2013-02-13T13:36:47+00:00

This changeset is aimed at fixing a few different but related
problems in the ACPI hotplug infrastructure.

First of all, since notify handlers may be run in parallel with
acpi_bus_scan(), acpi_bus_trim() and acpi_bus_hot_remove_device()
and some of them are installed for ACPI handles that have no struct
acpi_device objects attached (i.e. before those objects are created),
those notify handlers have to take acpi_scan_lock to prevent races
from taking place (e.g. a struct acpi_device is found to be present
for the given ACPI handle, but right after that it is removed by
acpi_bus_trim() running in parallel to the given notify handler).
Moreover, since some of them call acpi_bus_scan() and
acpi_bus_trim(), this leads to the conclusion that acpi_scan_lock
should be acquired by the callers of these two funtions rather by
these functions themselves.

For these reasons, make all notify handlers that can handle device
addition and eject events take acpi_scan_lock and remove the
acpi_scan_lock locking from acpi_bus_scan() and acpi_bus_trim().
Accordingly, update all of their users to make sure that they
are always called under acpi_scan_lock.

Furthermore, since eject operations are carried out asynchronously
with respect to the notify events that trigger them, with the help
of acpi_bus_hot_remove_device(), even if notify handlers take the
ACPI scan lock, it still is possible that, for example,
acpi_bus_trim() will run between acpi_bus_hot_remove_device() and
the notify handler that scheduled its execution and that
acpi_bus_trim() will remove the device node passed to
acpi_bus_hot_remove_device() for ejection.  In that case, the struct
acpi_device object obtained by acpi_bus_hot_remove_device() will be
invalid and not-so-funny things will ensue.  To protect agaist that,
make the users of acpi_bus_hot_remove_device() run get_device() on
ACPI device node objects that are about to be passed to it and make
acpi_bus_hot_remove_device() run put_device() on them and check if
their ACPI handles are not NULL (make acpi_device_unregister() clear
the device nodes' ACPI handles for that check to work).

Finally, observe that acpi_os_hotplug_execute() actually can fail,
in which case its caller ought to free memory allocated for the
context object to prevent leaks from happening.  It also needs to
run put_device() on the device node that it ran get_device() on
previously in that case.  Modify the code accordingly.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Yinghai Lu

ACPI / dock: Fix acpi_bus_get_device() check in drivers/acpi/dock.c

2013-02-02T19:10:23+00:00

acpi_bus_get_device() returns int not acpi_status.

The patch change not to apply ACPI_SUCCESS() to the return value of
acpi_bus_get_device().

Signed-off-by: Yasuaki Ishimatsu 
Signed-off-by: Rafael J. Wysocki

ACPI / scan: Make it clear that acpi_bus_trim() cannot fail

2013-01-25T23:27:44+00:00

Since acpi_bus_trim() cannot fail, change its definition to a void
function, so that its callers don't check the return value in vain
and update the callers.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Yinghai Lu 
Acked-by: Yasuaki Ishimatsu 
Acked-by: Toshi Kani

ACPI / scan: Drop acpi_bus_add() and use acpi_bus_scan() instead

2013-01-19T00:27:35+00:00

The only difference between acpi_bus_scan() and acpi_bus_add() is the
invocation of acpi_update_all_gpes() in the latter which in fact is
unnecessary, because acpi_update_all_gpes() has already been called
by acpi_scan_init() and the way it is implemented guarantees the next
invocations of it to do nothing.

For this reason, drop acpi_bus_add() and make all its callers use
acpi_bus_scan() directly instead of it.  Additionally, rearrange the
code in acpi_scan_init() slightly to improve the visibility of the
acpi_update_all_gpes() call in there.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Yinghai Lu

ACPI / scan: Drop the second argument of acpi_bus_trim()

2013-01-15T12:23:53+00:00

All callers of acpi_bus_trim() pass 1 (true) as the second argument
of it, so remove that argument entirely and change acpi_bus_trim()
to always behave as though it were 1.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Toshi Kani 
Acked-by: Yinghai Lu 
Acked-by: Yasuaki Ishimatsu

ACPI: Make acpi_bus_scan() and acpi_bus_add() take only one argument

2013-01-03T12:09:40+00:00

The callers of acpi_bus_add() usually assume that if it has
succeeded, then a struct acpi_device object has been attached to
the handle passed as the first argument.  Unfortunately, however,
this assumption is wrong, because acpi_bus_scan(), and acpi_bus_add()
too as a result, may return a pointer to a different struct
acpi_device object on success (it may be an object corresponding to
one of the descendant ACPI nodes in the namespace scope below that
handle).

For this reason, the callers of acpi_bus_add() who care about
whether or not a struct acpi_device object has been created for
its first argument need to check that using acpi_bus_get_device()
anyway, so the second argument of acpi_bus_add() is not really
useful for them.  The same observation applies to acpi_bus_scan()
executed directly from acpi_scan_init().

Therefore modify the relevant callers of acpi_bus_add() to check the
existence of the struct acpi_device in question with the help of
acpi_bus_get_device() and drop the no longer necessary second
argument of acpi_bus_add().  Accordingly, modify acpi_scan_init() to
use acpi_bus_get_device() to get acpi_root and drop the no longer
needed second argument of acpi_bus_scan().

Signed-off-by: Rafael J. Wysocki 
Acked-by: Yinghai Lu 
Acked-by: Toshi Kani

ACPI: Remove the arguments of acpi_bus_add() that are not used

2013-01-03T12:09:39+00:00

Notice that acpi_bus_add() uses only 2 of its 4 arguments and
redefine its header to match the body.  Update all of its callers as
necessary and observe that this leads to quite a number of removed
lines of code (Linus will like that).

Add a kerneldoc comment documenting acpi_bus_add() and wonder how
its callers make wrong assumptions about the second argument (make
note to self to take care of that later).

Signed-off-by: Rafael J. Wysocki 
Acked-by: Yinghai Lu 
Acked-by: Toshi Kani

ACPI: Update Dock hotplug error messages

2012-11-21T22:20:23+00:00

Updated Dock hotplug error messages with acpi_handle_()
and pr_().  Replaced acpi_get_name() & kfree() with
apci_handle_().  Added error status to the messages where
needed.

Signed-off-by: Toshi Kani 
Signed-off-by: Rafael J. Wysocki

ACPI: dock: Remove redundant ACPI NS walk

2012-11-14T23:16:00+00:00

Combined two ACPI namespace walks, which look for dock stations
and then bays separately, into a single walk.

Signed-off-by: Toshi Kani 
Reviewed-by: Yasuaki Ishimatsu 
Signed-off-by: Rafael J. Wysocki

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

2012-01-12T23:02:20+00:00

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 
Signed-off-by: Rusty Russell