linux/drivers/media/mc
Shuah Khan 50e7a31d30 media: Fix Media Controller API config checks
Smatch static checker warns that "mdev" can be null:

sound/usb/media.c:287 snd_media_device_create()
    warn: 'mdev' can also be NULL

If CONFIG_MEDIA_CONTROLLER is disabled, this file should not be included
in the build.

The below conditions in the sound/usb/Makefile are in place to ensure that
media.c isn't included in the build.

sound/usb/Makefile:
snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o

select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER &&
       (MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO)

The following config check in include/media/media-dev-allocator.h is
in place to enable the API only when CONFIG_MEDIA_CONTROLLER and
CONFIG_USB are enabled.

 #if defined(CONFIG_MEDIA_CONTROLLER) && defined(CONFIG_USB)

This check doesn't work as intended when CONFIG_USB=m. When CONFIG_USB=m,
CONFIG_USB_MODULE is defined and CONFIG_USB is not. The above config check
doesn't catch that CONFIG_USB is defined as a module and disables the API.
This results in sound/usb enabling Media Controller specific ALSA driver
code, while Media disables the Media Controller API.

Fix the problem requires two changes:

1. Change the check to use IS_ENABLED to detect when CONFIG_USB is enabled
   as a module or static. Since CONFIG_MEDIA_CONTROLLER is a bool, leave
   the check unchanged to be consistent with drivers/media/Makefile.

2. Change the drivers/media/mc/Makefile to include mc-dev-allocator.o
   in mc-objs when CONFIG_USB is enabled.

Link: https://lore.kernel.org/alsa-devel/YLeAvT+R22FQ%2FEyw@mwanda/

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2021-06-24 14:26:00 +02:00
..
Kconfig
Makefile media: Fix Media Controller API config checks 2021-06-24 14:26:00 +02:00
mc-dev-allocator.c
mc-device.c media: mc-device.c: change media_device_request_alloc to match media_ioctl_info 2020-08-29 08:15:23 +02:00
mc-devnode.c
mc-entity.c media: mc: mc-entity.c: Fix typo 2021-05-19 09:51:39 +02:00
mc-request.c media: mc-request.c: allow object_bind in QUEUED state 2021-06-02 11:41:54 +02:00