Needed for musl. https://git.alpinelinux.org/aports/tree/main/linux-headers/include-uapi-linux-swab-Fix-potentially-missing-__always_inline.patch From: Matt Redfearn Date: Wed, 3 Jan 2018 09:57:30 +0000 Subject: [PATCH] include/uapi/linux/swab: Fix potentially missing __always_inline MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining of some byteswap operations") added __always_inline to swab functions and commit 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers") added a definition of __always_inline for use in exported headers when the kernel's compiler.h is not available. However, since swab.h does not include stddef.h, if the header soup does not indirectly include it, the definition of __always_inline is missing, resulting in a compilation failure, which was observed compiling the perf tool using exported headers containing this commit: In file included from /usr/include/linux/byteorder/little_endian.h:12:0, from /usr/include/asm/byteorder.h:14, from tools/include/uapi/linux/perf_event.h:20, from perf.h:8, from builtin-bench.c:18: /usr/include/linux/swab.h:160:8: error: unknown type name ‘__always_inline’ static __always_inline __u16 __swab16p(const __u16 *p) Fix this by replacing the inclusion of linux/compiler.h with linux/stddef.h to ensure that we pick up that definition if required, without relying on it's indirect inclusion. compiler.h is then included indirectly, via stddef.h. Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers") Signed-off-by: Matt Redfearn --- a/include/uapi/linux/swab.h +++ b/include/uapi/linux/swab.h @@ -3,7 +3,7 @@ #define _UAPI_LINUX_SWAB_H #include -#include +#include #include #include