MIPS platforms building with recent kernel headers and the musl-libc toolchain will expose the following build failure: mmap.c: In function 'mmap_f': mmap.c:196:12: error: 'MAP_SYNC' undeclared (first use in this function); did you mean 'MS_SYNC'? 196 | flags = MAP_SYNC | MAP_SHARED_VALIDATE; | ^~~~~~~~ | MS_SYNC mmap.c:196:12: note: each undeclared identifier is reported only once for each function it appears in make[4]: *** [../include/buildrules:81: mmap.o] Error 1 The reason for that is that the linux.h header file which intends to provide a fallback definition for MAP_SYNC and MAP_SHARED_VALIDATE is included too early through: input.h -> libfrog/projects.h -> xfs.h -> linux.h and this happens *before* sys/mman.h is included. sys/mman.h -> bits/mman.h which has a: #undef MAP_SYNC see: https://git.musl-libc.org/cgit/musl/tree/arch/mips/bits/mman.h#n21 The end result is that sys/mman.h being included for the first time ends-up overriding the HAVE_MAP_SYNC fallbacks. To remedy that, make sure that linux.h is updated to include sys/mman.h such that its fallbacks are independent of the inclusion order. As a consequence this forces us to ensure that we do not re-define accidentally MAP_SYNC or MAP_SHARED_VALIDATE so we protect against that. Fixes: dad796834cb9 ("xfs_io: add MAP_SYNC support to mmap()") Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx> --- include/linux.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux.h b/include/linux.h index 3d9f4e3dca80..c3cc8e30c677 100644 --- a/include/linux.h +++ b/include/linux.h @@ -252,8 +252,13 @@ struct fsxattr { #endif #ifndef HAVE_MAP_SYNC +#include <sys/mman.h> +#ifndef MAP_SYNC #define MAP_SYNC 0 +#endif +#ifndef MAP_SHARED_VALIDATE #define MAP_SHARED_VALIDATE 0 +#endif #else #include <asm-generic/mman.h> #include <asm-generic/mman-common.h> -- 2.25.1