The function software_node_notify() - the function that creates
and removes the symlinks between the node and the device - was
called unconditionally in device_add_software_node() and
device_remove_software_node(), but it needs to be called in
those functions only in the special case where the node is
added to a device that has already been registered.

This fixes NULL pointer dereference that happens if
device_remove_software_node() is used with device that was
never registered.

Fixes: b622b24519f5 ("software node: Allow node addition to already existing device")
Reported-and-tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If the node is added to an already exiting device, the node
needs to be also linked to the device separately.

This will make sure the reference count is kept in balance
also when the node is injected to a device afterwards.

Fixes: e68d0119e328 ("software node: Introduce device_add_software_node()")
Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210414075438.64547-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since we don't use structure field layout randomization
the manual shuffling can affect some macros, in particular
kobj_to_swnode(), which becomes a no-op when kobj member
is the first one in the struct swnode.

Bloat-o-meter statistics for swnode.o:

  add/remove: 0/0 grow/shrink: 2/10 up/down: 9/-100 (-91)
  Total: Before=7217, After=7126, chg -1.26%

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210329151207.36619-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Deduplicate conditional and assignment in fwnode_create_software_node(),
i.e. parent is checked in two out of three cases and parent software node
is assigned by to_swnode() call.

Reviewed-by: Daniel Scally <djrscally@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210329151207.36619-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce software_node_alloc() and software_node_free() helpers.
This will help with code readability and maintenance.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210329151207.36619-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently we have a slightly twisted logic in swnode_register().
It frees resources that it doesn't allocate on error path and
in once case it relies on the ->release() implementation.

Untwist the logic by freeing resources explicitly when swnode_register()
fails. Currently it happens only in fwnode_create_software_node().

Tested-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210329151207.36619-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

After a few updates against swnode APIs the kernel documentation, i.e.
for swnode group registration and unregistration deviates from the one
for swnode array. In general, the same rules are applied to both.
Hence, synchronize descriptions of swnode array and group APIs

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210308103644.81960-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The function device_add_software_node() was meant to
register the node supplied to it, but only if that node
wasn't already registered. Right now the function attempts
to always register the node. That will cause a failure with
nodes that are already registered.

Fixing that by incrementing the reference count of the nodes
that have already been registered, and only registering the
new nodes. Also, clarifying the behaviour in the function
documentation.

Fixes: e68d0119e328 ("software node: Introduce device_add_software_node()")
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Software node can not be registered before its parent.

Fixes: 80488a6b1d3c ("software node: Add support for static node descriptors")
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull media updates from Mauro Carvalho Chehab:

 - some core fixes in VB2 mem2mem support

 - some improvements and cleanups in V4L2 async kAPI

 - newer controls in V4L2 API for H-264 and HEVC codecs

 - allegro-dvt driver was promoted from staging

 - new i2c sendor drivers: imx334, ov5648, ov8865

 - new automobile camera module: rdacm21

 - ipu3 cio2 driver started gained support for some ACPI BIOSes

 - new ATSC frontend: MaxLinear mxl692 VSB tuner/demod

 - the SMIA/CCS driver gained more support for CSS standard

 - several driver fixes, updates and improvements

* tag 'media/v5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (362 commits)
  media: v4l: async: Fix kerneldoc documentation for async functions
  media: i2c: max9271: Add MODULE_* macros
  media: i2c: Kconfig: Make MAX9271 a module
  media: imx334: 'ret' is uninitialized, should have been PTR_ERR()
  media: i2c: Add imx334 camera sensor driver
  media: dt-bindings: media: Add bindings for imx334
  media: ov8856: Configure sensor for GRBG Bayer for all modes
  media: i2c: imx219: Implement V4L2_CID_LINK_FREQ control
  media: ov5675: fix vflip/hflip control
  media: ipu3-cio2: Build bridge only if ACPI is enabled
  media: Remove the legacy v4l2-clk API
  media: ov6650: Use the generic clock framework
  media: mt9m111: Use the generic clock framework
  media: ov9640: Use the generic clock framework
  media: pxa_camera: Drop the v4l2-clk clock register
  media: mach-pxa: Register the camera sensor fixed-rate clock
  media: i2c: imx258: get clock from device properties and enable it via runtime PM
  media: i2c: imx258: simplify getting state container
  media: i2c: imx258: add support for binding via device tree
  media: dt-bindings: media: imx258: add bindings for IMX258 sensor
  ...