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* [PATCH] media: Fix Media Controller API config checks
@ 2021-06-11  1:58 ` Shuah Khan
  0 siblings, 0 replies; 10+ messages in thread
From: Shuah Khan @ 2021-06-11  1:58 UTC (permalink / raw)
  To: sakari.ailus, laurent.pinchart, dan.carpenter, mchehab
  Cc: Shuah Khan, linux-media, linux-kernel, alsa-devel

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 y or m.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/alsa-devel/YLeAvT+R22FQ%2FEyw@mwanda/
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---
 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..140f0a78540e 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 ($(CONFIG_USB),y)
+ifeq ($(CONFIG_USB),$(filter $(CONFIG_USB),y m))
 	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


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-06-16  3:16 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-11  1:58 [PATCH] media: Fix Media Controller API config checks Shuah Khan
2021-06-11  1:58 ` Shuah Khan
2021-06-15 13:36 ` Hans Verkuil
2021-06-15 13:36   ` Hans Verkuil
2021-06-15 14:09   ` Shuah Khan
2021-06-15 14:09     ` Shuah Khan
2021-06-15 16:55   ` Shuah Khan
2021-06-15 16:55     ` Shuah Khan
2021-06-16  3:15     ` Shuah Khan
2021-06-16  3:15       ` Shuah Khan

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