On Sun, Sep 21, 2014 at 06:43:06PM +0200, Oleg Nesterov wrote:
> Kill _NSIG_WORDS_is_unsupported_size(), use BUILD_BUG() instead.
> This simplifies the code, avoids the nested-externs warnings, and
> this way we do not defer the problem to linker.
>
> Also, fix the indentation in _SIG_SET_BINOP() and _SIG_SET_OP().
>
> Note: this patch assumes that the code like "if (0) BUILD_BUG();"
> is valid. If not (say __compiletime_error() is not defined and thus
> __compiletime_error_fallback() uses a negative array) we should fix
> BUILD_BUG() and/or BUILD_BUG_ON_MSG(). This code should be fine by
> definition, this is the documented purpose of BUILD_BUG().
>
> Reported-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Thanks for posting this.
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> include/linux/signal.h | 28 ++++++++++++----------------
> 1 files changed, 12 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/signal.h b/include/linux/signal.h
> index 750196f..14acfd5 100644
> --- a/include/linux/signal.h
> +++ b/include/linux/signal.h
> @@ -67,7 +67,6 @@ static inline int sigismember(sigset_t *set, int _sig)
>
> static inline int sigisemptyset(sigset_t *set)
> {
> - extern void _NSIG_WORDS_is_unsupported_size(void);
> switch (_NSIG_WORDS) {
> case 4:
> return (set->sig[3] | set->sig[2] |
> @@ -77,7 +76,7 @@ static inline int sigisemptyset(sigset_t *set)
> case 1:
> return set->sig[0] == 0;
> default:
> - _NSIG_WORDS_is_unsupported_size();
> + BUILD_BUG();
> return 0;
> }
> }
> @@ -90,24 +89,23 @@ static inline int sigisemptyset(sigset_t *set)
> #define _SIG_SET_BINOP(name, op) \
> static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
> { \
> - extern void _NSIG_WORDS_is_unsupported_size(void); \
> unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \
> \
> switch (_NSIG_WORDS) { \
> - case 4: \
> + case 4: \
> a3 = a->sig[3]; a2 = a->sig[2]; \
> b3 = b->sig[3]; b2 = b->sig[2]; \
> r->sig[3] = op(a3, b3); \
> r->sig[2] = op(a2, b2); \
> - case 2: \
> + case 2: \
> a1 = a->sig[1]; b1 = b->sig[1]; \
> r->sig[1] = op(a1, b1); \
> - case 1: \
> + case 1: \
> a0 = a->sig[0]; b0 = b->sig[0]; \
> r->sig[0] = op(a0, b0); \
> break; \
> - default: \
> - _NSIG_WORDS_is_unsupported_size(); \
> + default: \
> + BUILD_BUG(); \
> } \
> }
>
> @@ -128,16 +126,14 @@ _SIG_SET_BINOP(sigandnsets, _sig_andn)
> #define _SIG_SET_OP(name, op) \
> static inline void name(sigset_t *set) \
> { \
> - extern void _NSIG_WORDS_is_unsupported_size(void); \
> - \
> switch (_NSIG_WORDS) { \
> - case 4: set->sig[3] = op(set->sig[3]); \
> - set->sig[2] = op(set->sig[2]); \
> - case 2: set->sig[1] = op(set->sig[1]); \
> - case 1: set->sig[0] = op(set->sig[0]); \
> + case 4: set->sig[3] = op(set->sig[3]); \
> + set->sig[2] = op(set->sig[2]); \
> + case 2: set->sig[1] = op(set->sig[1]); \
> + case 1: set->sig[0] = op(set->sig[0]); \
> break; \
> - default: \
> - _NSIG_WORDS_is_unsupported_size(); \
> + default: \
> + BUILD_BUG(); \
> } \
> }
>
> --
> 1.5.5.1
>
>
> --
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