From: Darrick J. Wong <djwong@xxxxxxxxxx> Port the IS_ENABLED macro from the kernel so that it can be used in libxfs. This requires a bit of hygiene on our part -- any CONFIG_XFS_* define in userspace that have counterparts in the kernel must be defined to 1 (and not simply define'd) so that the macro works, because the kernel translates CONFIG_FOO=y in .config to #define CONFIG_FOO 1. Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> --- include/libxfs.h | 6 +++- include/platform_defs.h | 63 +++++++++++++++++++++++++++++++++++++++++++++++ libxfs/libxfs_priv.h | 5 ++-- 3 files changed, 70 insertions(+), 4 deletions(-) diff --git a/include/libxfs.h b/include/libxfs.h index 17cf619f0544aa..fe8e6584f1caca 100644 --- a/include/libxfs.h +++ b/include/libxfs.h @@ -7,10 +7,12 @@ #ifndef __LIBXFS_H__ #define __LIBXFS_H__ +/* CONFIG_XFS_* must be defined to 1 to work with IS_ENABLED() */ + /* For userspace XFS_RT is always defined */ -#define CONFIG_XFS_RT +#define CONFIG_XFS_RT 1 /* Ditto in-memory btrees */ -#define CONFIG_XFS_BTREE_IN_MEM +#define CONFIG_XFS_BTREE_IN_MEM 1 #include "libxfs_api_defs.h" #include "platform_defs.h" diff --git a/include/platform_defs.h b/include/platform_defs.h index c01d4c42674669..a3644dea41cdef 100644 --- a/include/platform_defs.h +++ b/include/platform_defs.h @@ -165,4 +165,67 @@ static inline size_t __ab_c_size(size_t a, size_t b, size_t c) # define barrier() __memory_barrier() #endif +/* stuff from include/linux/kconfig.h */ +#define __ARG_PLACEHOLDER_1 0, +#define __take_second_arg(__ignored, val, ...) val + +/* + * The use of "&&" / "||" is limited in certain expressions. + * The following enable to calculate "and" / "or" with macro expansion only. + */ +#define __and(x, y) ___and(x, y) +#define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y) +#define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0) + +#define __or(x, y) ___or(x, y) +#define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y) +#define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y) + +/* + * Helper macros to use CONFIG_ options in C/CPP expressions. Note that + * these only work with boolean and tristate options. + */ + +/* + * Getting something that works in C and CPP for an arg that may or may + * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1" + * we match on the placeholder define, insert the "0," for arg1 and generate + * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one). + * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when + * the last step cherry picks the 2nd arg, we get a zero. + */ +#define __is_defined(x) ___is_defined(x) +#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val) +#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0) + +/* + * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0 + * otherwise. For boolean options, this is equivalent to + * IS_ENABLED(CONFIG_FOO). + */ +#define IS_BUILTIN(option) __is_defined(option) + +/* + * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 + * otherwise. CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1" in + * autoconf.h. + */ +#define IS_MODULE(option) __is_defined(option##_MODULE) + +/* + * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled + * code can call a function defined in code compiled based on CONFIG_FOO. + * This is similar to IS_ENABLED(), but returns false when invoked from + * built-in code when CONFIG_FOO is set to 'm'. + */ +#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \ + __and(IS_MODULE(option), __is_defined(MODULE))) + +/* + * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', + * 0 otherwise. Note that CONFIG_FOO=y results in "#define CONFIG_FOO 1" in + * autoconf.h, while CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1". + */ +#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) + #endif /* __XFS_PLATFORM_DEFS_H__ */ diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h index b720cc5fac94ff..fa025aeb09712b 100644 --- a/libxfs/libxfs_priv.h +++ b/libxfs/libxfs_priv.h @@ -37,8 +37,9 @@ #ifndef __LIBXFS_INTERNAL_XFS_H__ #define __LIBXFS_INTERNAL_XFS_H__ -#define CONFIG_XFS_RT -#define CONFIG_XFS_BTREE_IN_MEM +/* CONFIG_XFS_* must be defined to 1 to work with IS_ENABLED() */ +#define CONFIG_XFS_RT 1 +#define CONFIG_XFS_BTREE_IN_MEM 1 #include "libxfs_api_defs.h" #include "platform_defs.h"
