The macro __is_constexpr() causes sparse to report the following:
warning: expression using sizeof(void)
Avoid this by using __builtin_constant_p() instead.
Fixes: 3c8ba0d61d04 ("kernel.h: Retain constant expression output for max()/min()") Signed-off-by: Bart Van Assche bart.vanassche@wdc.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Martin Uecker Martin.Uecker@med.uni-goettingen.de Cc: Kees Cook keescook@chromium.org Cc: Ingo Molnar mingo@kernel.org Cc: Miguel Ojeda miguel.ojeda.sandonis@gmail.com Cc: stable@vger.kernel.org --- include/linux/kernel.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d23123238534..a9f0d0d48971 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -811,13 +811,19 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
+#ifndef __CHECKER__ /* * This returns a constant expression while determining if an argument is * a constant expression, most importantly without evaluating the argument. - * Glory to Martin Uecker Martin.Uecker@med.uni-goettingen.de + * Glory to Martin Uecker Martin.Uecker@med.uni-goettingen.de. However, this + * macro causes sparse to report the warning "expression using sizeof(void)". + * Hence use __builtin_constant_p() instead when using sparse. */ #define __is_constexpr(x) \ (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) +#else +#define __is_constexpr(x) __builtin_constant_p((x)) +#endif
#define __no_side_effects(x, y) \ (__is_constexpr(x) && __is_constexpr(y))