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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>
63 lines
2.2 KiB
C
63 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* media-dev-allocator.h - Media Controller Device Allocator API
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*
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* Copyright (c) 2019 Shuah Khan <shuah@kernel.org>
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*
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* Credits: Suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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*/
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/*
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* This file adds a global ref-counted Media Controller Device Instance API.
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* A system wide global media device list is managed and each media device
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* includes a kref count. The last put on the media device releases the media
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* device instance.
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*/
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#ifndef _MEDIA_DEV_ALLOCATOR_H
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#define _MEDIA_DEV_ALLOCATOR_H
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struct usb_device;
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#if defined(CONFIG_MEDIA_CONTROLLER) && IS_ENABLED(CONFIG_USB)
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/**
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* media_device_usb_allocate() - Allocate and return struct &media device
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*
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* @udev: struct &usb_device pointer
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* @module_name: should be filled with %KBUILD_MODNAME
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* @owner: struct module pointer %THIS_MODULE for the driver.
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* %THIS_MODULE is null for a built-in driver.
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* It is safe even when %THIS_MODULE is null.
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*
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* This interface should be called to allocate a Media Device when multiple
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* drivers share usb_device and the media device. This interface allocates
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* &media_device structure and calls media_device_usb_init() to initialize
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* it.
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*
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*/
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struct media_device *media_device_usb_allocate(struct usb_device *udev,
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const char *module_name,
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struct module *owner);
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/**
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* media_device_delete() - Release media device. Calls kref_put().
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*
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* @mdev: struct &media_device pointer
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* @module_name: should be filled with %KBUILD_MODNAME
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* @owner: struct module pointer %THIS_MODULE for the driver.
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* %THIS_MODULE is null for a built-in driver.
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* It is safe even when %THIS_MODULE is null.
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*
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* This interface should be called to put Media Device Instance kref.
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*/
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void media_device_delete(struct media_device *mdev, const char *module_name,
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struct module *owner);
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#else
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static inline struct media_device *media_device_usb_allocate(
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struct usb_device *udev, const char *module_name,
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struct module *owner)
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{ return NULL; }
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static inline void media_device_delete(
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struct media_device *mdev, const char *module_name,
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struct module *owner) { }
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#endif /* CONFIG_MEDIA_CONTROLLER && CONFIG_USB */
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#endif /* _MEDIA_DEV_ALLOCATOR_H */
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