4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> commit b5bf1733d6a391c4e90ea8f8468d83023be74a2a upstream. For cases where implicit fall through case labels are intended, to let us inform that to gcc >= 7: CC /tmp/build/perf/util/string.o util/string.c: In function 'perf_atoll': util/string.c:22:7: error: this statement may fall through [-Werror=implicit-fallthrough=] if (*p) ^ util/string.c:24:3: note: here case '\0': ^~~~ So we introduce: #define __fallthrough __attribute__ ((fallthrough)) And use it in such cases. Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> Cc: David Ahern <dsahern@xxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Wang Nan <wangnan0@xxxxxxxxxx> Cc: William Cohen <wcohen@xxxxxxxxxx> Link: http://lkml.kernel.org/n/tip-qnpig0xfop4hwv6k4mv1wts5@xxxxxxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/include/linux/compiler.h | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -115,4 +115,13 @@ static __always_inline void __write_once #define WRITE_ONCE(x, val) \ ({ union { typeof(x) __val; char __c[1]; } __u = { .__val = (val) }; __write_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) + +#ifndef __fallthrough +# if defined(__GNUC__) && __GNUC__ >= 7 +# define __fallthrough __attribute__ ((fallthrough)) +# else +# define __fallthrough +# endif +#endif + #endif /* _TOOLS_LINUX_COMPILER_H */