On Thu, May 08, 2014 at 08:31:25AM +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.b...@intel.com>
>
> Usually, BUG_ON and friends aren't even evaluated in sparse, but
> recently compiletime_assert_atomic_type() was added, and that now
> results in a sparse warning every time it is used.
>
> The reason turns out to be the temporary variable, after it sparse
> no longer considers the value to be a constant, and results in a
> warning and an error. The error is the more annoying part of this
> as it suppresses any further warnings in the same file, hiding
> other problems.
>
> Since this is all about compile time and the condition should be
> side-effect free to start with, there's no downside (apart maybe
> from a slight compilation time penalty?) to just duplicating it,
> leaving sparse able to evaluate it at check time, getting rid of
> the warning and error.
>
> Signed-off-by: Johannes Berg <johannes.b...@intel.com>
Acked-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> ---
> include/linux/compiler.h | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 2472740d7ab2..38c0e00ddef8 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -324,11 +324,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f,
> int val, int expect);
>
> #define __compiletime_assert(condition, msg, prefix, suffix) \
> do { \
> - bool __cond = !(condition); \
> extern void prefix ## suffix(void) __compiletime_error(msg); \
> - if (__cond) \
> + if (!(condition)) \
> prefix ## suffix(); \
> - __compiletime_error_fallback(__cond); \
> + __compiletime_error_fallback(!(condition)); \
> } while (0)
>
> #define _compiletime_assert(condition, msg, prefix, suffix) \
> --
> 2.0.0.rc0
>
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