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Patch series "linux/const.h: cleanups of macros such as UL(), _BITUL(), BIT() etc", v3. ARM, ARM64, UniCore32 define UL() as a shorthand of _AC(..., UL). More architectures may introduce it in the future. UL() is arch-agnostic, and useful. So let's move it to include/linux/const.h Currently, <asm/memory.h> must be included to use UL(). It pulls in more bloats just for defining some bit macros. I posted V2 one year ago. The previous posts are: https://patchwork.kernel.org/patch/9498273/ https://patchwork.kernel.org/patch/9498275/ https://patchwork.kernel.org/patch/9498269/ https://patchwork.kernel.org/patch/9498271/ At that time, what blocked this series was a comment from David Howells: You need to be very careful doing this. Some userspace stuff depends on the guard macro names on the kernel header files. (https://patchwork.kernel.org/patch/9498275/) Looking at the code closer, I noticed this is not a problem. See the following line. https://github.com/torvalds/linux/blob/v4.16-rc2/scripts/headers_install.sh#L40 scripts/headers_install.sh rips off _UAPI prefix from guard macro names. I ran "make headers_install" and confirmed the result is what I expect. So, we can prefix the include guard of include/uapi/linux/const.h, and add a new include/linux/const.h. This patch (of 4): I am going to add include/linux/const.h for the kernel space. Add _UAPI to the include guard of include/uapi/linux/const.h to prepare for that. Please notice the guard name of the exported one will be kept as-is. So, this commit has no impact to the userspace even if some userspace stuff depends on the guard macro names. scripts/headers_install.sh processes exported headers by SED, and rips off "_UAPI" from guard macro names. #ifndef _UAPI_LINUX_CONST_H #define _UAPI_LINUX_CONST_H will be turned into #ifndef _LINUX_CONST_H #define _LINUX_CONST_H Link: http://lkml.kernel.org/r/1519301715-31798-2-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: David Howells <dhowells@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.