On Thu, Oct 07, 2021 at 12:51:27PM +0300, Andy Shevchenko wrote:
> kernel.h is being used as a dump for all kinds of stuff for a long time.
> Here is the attempt cleaning it up by splitting out container_of() and
> typeof_member() macros.
>
> At the same time convert users in the header and other folders to use it.
> Though for time being include new header back to kernel.h to avoid twisted
> indirected includes for existing users.
>
> Note, there are _a lot_ of headers and modules that include kernel.h solely
> for one of these macros and this allows to unburden compiler for the twisted
> inclusion paths and to make new code cleaner in the future.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> include/kunit/test.h | 2 ++
> include/linux/container_of.h | 37 ++++++++++++++++++++++++++++++++++++
> include/linux/kernel.h | 31 +-----------------------------
> include/linux/kobject.h | 1 +
> include/linux/list.h | 6 ++++--
> include/linux/llist.h | 4 +++-
> include/linux/plist.h | 5 ++++-
> include/media/media-entity.h | 3 ++-
> lib/radix-tree.c | 6 +++++-
> lib/rhashtable.c | 1 +
> 10 files changed, 60 insertions(+), 36 deletions(-)
> create mode 100644 include/linux/container_of.h
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index 24b40e5c160b..4d498f496790 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -11,6 +11,8 @@
>
> #include <kunit/assert.h>
> #include <kunit/try-catch.h>
> +
> +#include <linux/container_of.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/slab.h>
> diff --git a/include/linux/container_of.h b/include/linux/container_of.h
> new file mode 100644
> index 000000000000..f6ee1be0e784
> --- /dev/null
> +++ b/include/linux/container_of.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_CONTAINER_OF_H
> +#define _LINUX_CONTAINER_OF_H
> +
> +#define typeof_member(T, m) typeof(((T*)0)->m)
> +
> +/**
> + * container_of - cast a member of a structure out to the containing structure
> + * @ptr: the pointer to the member.
> + * @type: the type of the container struct this is embedded in.
> + * @member: the name of the member within the struct.
> + *
> + */
> +#define container_of(ptr, type, member) ({ \
> + void *__mptr = (void *)(ptr); \
> + BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
> + !__same_type(*(ptr), void), \
> + "pointer type mismatch in container_of()"); \
> + ((type *)(__mptr - offsetof(type, member))); })
> +
> +/**
> + * container_of_safe - cast a member of a structure out to the containing structure
> + * @ptr: the pointer to the member.
> + * @type: the type of the container struct this is embedded in.
> + * @member: the name of the member within the struct.
> + *
> + * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
> + */
> +#define container_of_safe(ptr, type, member) ({ \
> + void *__mptr = (void *)(ptr); \
> + BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
> + !__same_type(*(ptr), void), \
> + "pointer type mismatch in container_of()"); \
> + IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
> + ((type *)(__mptr - offsetof(type, member))); })
> +
> +#endif /* _LINUX_CONTAINER_OF_H */
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index d416fe3165cb..ad9fdcce9dcf 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -9,6 +9,7 @@
> #include <linux/stddef.h>
> #include <linux/types.h>
> #include <linux/compiler.h>
> +#include <linux/container_of.h>
> #include <linux/bitops.h>
> #include <linux/kstrtox.h>
> #include <linux/log2.h>
> @@ -482,36 +483,6 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
> #define __CONCAT(a, b) a ## b
> #define CONCATENATE(a, b) __CONCAT(a, b)
>
> -/**
> - * container_of - cast a member of a structure out to the containing structure
> - * @ptr: the pointer to the member.
> - * @type: the type of the container struct this is embedded in.
> - * @member: the name of the member within the struct.
> - *
> - */
> -#define container_of(ptr, type, member) ({ \
> - void *__mptr = (void *)(ptr); \
> - BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
> - !__same_type(*(ptr), void), \
> - "pointer type mismatch in container_of()"); \
> - ((type *)(__mptr - offsetof(type, member))); })
> -
> -/**
> - * container_of_safe - cast a member of a structure out to the containing structure
> - * @ptr: the pointer to the member.
> - * @type: the type of the container struct this is embedded in.
> - * @member: the name of the member within the struct.
> - *
> - * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
> - */
> -#define container_of_safe(ptr, type, member) ({ \
> - void *__mptr = (void *)(ptr); \
> - BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
> - !__same_type(*(ptr), void), \
> - "pointer type mismatch in container_of()"); \
> - IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
> - ((type *)(__mptr - offsetof(type, member))); })
> -
> /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
> #ifdef CONFIG_FTRACE_MCOUNT_RECORD
> # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
> index efd56f990a46..bf8371e58b17 100644
> --- a/include/linux/kobject.h
> +++ b/include/linux/kobject.h
> @@ -15,6 +15,7 @@
> #ifndef _KOBJECT_H_
> #define _KOBJECT_H_
>
> +#include <linux/container_of.h>
> #include <linux/types.h>
> #include <linux/list.h>
> #include <linux/sysfs.h>
> diff --git a/include/linux/list.h b/include/linux/list.h
> index f2af4b4aa4e9..5dc679b373da 100644
> --- a/include/linux/list.h
> +++ b/include/linux/list.h
> @@ -2,11 +2,13 @@
> #ifndef _LINUX_LIST_H
> #define _LINUX_LIST_H
>
> +#include <linux/container_of.h>
> +#include <linux/const.h>
> #include <linux/types.h>
> #include <linux/stddef.h>
> #include <linux/poison.h>
> -#include <linux/const.h>
> -#include <linux/kernel.h>
> +
> +#include <asm/barrier.h>
>
> /*
> * Circular doubly linked list implementation.
This change looks odd.
You already have kernel.h including container_of.h, so why not have a
series that does:
- create container_of.h and have kernel.h include it
- multiple patches that remove kernel.h and use container_of.h
instead only.
- multiple patches that remove kernel.h and use container_of.h
and other .h files (like list.h seems to need here.)
- remove container_of.h from kernel.h
Mushing them all together here makes this really hard to understand why
this change is needed here.
thanks,
greg k-h
