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signal: use BUILD_BUG() instead of _NSIG_WORDS_is_unsupported_size()

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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().

[sfr@canb.auug.org.au: fix powerpc build failures]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-10-13 15:53:33 -07:00 committed by Linus Torvalds
parent 877aabd6ce
commit 1c3bea0e71
1 changed files with 13 additions and 16 deletions
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29
include/linux/signal.h
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@ -2,6 +2,7 @@
#define _LINUX_SIGNAL_H
#include <linux/list.h>
#include <linux/bug.h>
#include <uapi/linux/signal.h>
struct task_struct;
@ -67,7 +68,6 @@ 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 +77,7 @@ 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 +90,23 @@ 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 +127,14 @@ _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(); \
} \
}