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-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o
select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER &&
(MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO)
The following config check in include/media/media-dev-allocator.h is
in place to enable the API only when CONFIG_MEDIA_CONTROLLER and
CONFIG_USB are enabled.
#if defined(CONFIG_MEDIA_CONTROLLER) && defined(CONFIG_USB)
This check doesn't work as intended when CONFIG_USB=m. When CONFIG_USB=m,
CONFIG_USB_MODULE is defined and CONFIG_USB is not. The above config check
doesn't catch that CONFIG_USB is defined as a module and disables the API.
This results in sound/usb enabling Media Controller specific ALSA driver
code, while Media disables the Media Controller API.
Fix the problem requires two changes:
1. Change the check to use IS_ENABLED to detect when CONFIG_USB is enabled
as a module or static. Since CONFIG_MEDIA_CONTROLLER is a bool, leave
the check unchanged to be consistent with drivers/media/Makefile.
2. Change the drivers/media/mc/Makefile to include mc-dev-allocator.o
in mc-objs when CONFIG_USB is enabled.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/alsa-devel/YLeAvT+R22FQ%2FEyw@mwanda/
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
- Fixed the drivers/media/mc/Makefile incorrect logic to check
CONFIG_USB value. Test with CONFIG_USB_SUPPORT enabled/disabled
CONFIG_USB y/m and disabled.
drivers/media/mc/Makefile | 2 +-
include/media/media-dev-allocator.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/mc/Makefile b/drivers/media/mc/Makefile
index 119037f0e686..2b7af42ba59c 100644
--- a/drivers/media/mc/Makefile
+++ b/drivers/media/mc/Makefile
@@ -3,7 +3,7 @@
mc-objs := mc-device.o mc-devnode.o mc-entity.o \
mc-request.o
-ifeq ($(CONFIG_USB),y)
+ifneq ($(CONFIG_USB),)
mc-objs += mc-dev-allocator.o
endif
diff --git a/include/media/media-dev-allocator.h b/include/media/media-dev-allocator.h
index b35ea6062596..2ab54d426c64 100644
--- a/include/media/media-dev-allocator.h
+++ b/include/media/media-dev-allocator.h
@@ -19,7 +19,7 @@
struct usb_device;
-#if defined(CONFIG_MEDIA_CONTROLLER) && defined(CONFIG_USB)
+#if defined(CONFIG_MEDIA_CONTROLLER) && IS_ENABLED(CONFIG_USB)
/**
* media_device_usb_allocate() - Allocate and return struct &media device
*
--
2.30.2
