diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2014-03-02 13:09:47 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-14 06:42:19 -0700 |
| commit | f26c70a452dc0507bf7d3d2c3158ee7808e14f1c (patch) | |
| tree | 7626bda5305bd7c9013d48ef50d030ade70b4b70 /include | |
| parent | 47c4534a109e45700d1d1c8467c2b5a618212d81 (diff) | |
futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test
commit 03b8c7b623c80af264c4c8d6111e5c6289933666 upstream.
If an architecture has futex_atomic_cmpxchg_inatomic() implemented and there
is no runtime check necessary, allow to skip the test within futex_init().
This allows to get rid of some code which would always give the same result,
and also allows the compiler to optimize a couple of if statements away.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Finn Thain <fthain@telegraphics.com.au>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20140302120947.GA3641@osiris
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[geert: Backported to v3.10..v3.13]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/futex.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h index b0d95cac826..6435f46d6e1 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -55,7 +55,11 @@ union futex_key { #ifdef CONFIG_FUTEX extern void exit_robust_list(struct task_struct *curr); extern void exit_pi_state_list(struct task_struct *curr); +#ifdef CONFIG_HAVE_FUTEX_CMPXCHG +#define futex_cmpxchg_enabled 1 +#else extern int futex_cmpxchg_enabled; +#endif #else static inline void exit_robust_list(struct task_struct *curr) { |