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Fix futex(2) detection and use

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Commit 22e7fc34c44c5ef95abf4fed429f2345410cc82c introduced a regression:
futexes were always disabled and the emulated codepath was always being
used.  That commit was in response to an originally buggy
implementationt hat wrote junk into config.h (but happened to be working
properly).

Fix up the mess and while we're at it, close bug #631231 by including
syscall.h from the correct location and using __NR_futex instead of
SYS_futex.

Closes #631231.
This commit is contained in:
Ryan Lortie 2011-05-28 17:27:12 -04:00
parent 8382135265
commit 858a328792
2 changed files with 6 additions and 8 deletions
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8
configure.ac
View File

@ -2580,22 +2580,20 @@ dnl ************************
AC_MSG_CHECKING([for futex(2) system call])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
#include <linux/futex.h>
#include <syscall.h>
#include <sys/syscall.h>
#include <unistd.h>
],[
int
main (void)
{
/* it is not like this actually runs or anything... */
syscall (SYS_futex, NULL, FUTEX_WAKE, FUTEX_WAIT);
syscall (__NR_futex, NULL, FUTEX_WAKE, FUTEX_WAIT);
return 0;
}
])],
[
AC_MSG_RESULT(yes)
if test "$have_futex" = "yes"; then
AC_DEFINE(HAVE_FUTEX, 1, [we have the futex(2) system call])
fi
AC_DEFINE(HAVE_FUTEX, 1, [we have the futex(2) system call])
],
[
AC_MSG_RESULT(no)

6
glib/gbitlock.c
View File

@ -56,7 +56,7 @@ _g_futex_thread_init (void) {
* If anyone actually gets bit by this, please file a bug. :)
*/
#include <linux/futex.h>
#include <syscall.h>
#include <sys/syscall.h>
#include <unistd.h>
/* < private >
@ -80,7 +80,7 @@ static void
g_futex_wait (const volatile gint *address,
gint value)
{
syscall (SYS_futex, address, (gsize) FUTEX_WAIT, (gsize) value, NULL);
syscall (__NR_futex, address, (gsize) FUTEX_WAIT, (gsize) value, NULL);
}
/* < private >
@ -97,7 +97,7 @@ g_futex_wait (const volatile gint *address,
static void
g_futex_wake (const volatile gint *address)
{
syscall (SYS_futex, address, (gsize) FUTEX_WAKE, (gsize) 1, NULL);
syscall (__NR_futex, address, (gsize) FUTEX_WAKE, (gsize) 1, NULL);
}
#else