On 07/19/24 at 12:38pm, Uros Bizjak wrote:
> Use atomic_try_cmpxchg_acquire(*ptr, &old, new) instead of
> atomic_cmpxchg_acquire(*ptr, old, new) == old in kexec_trylock().
> x86 CMPXCHG instruction returns success in ZF flag, so
> this change saves a compare after cmpxchg.
Seems it can simplify code even though on non-x86 arch, should we
replace atomic_try_cmpxchg_acquire() with atomic_try_cmpxchg_acquire()
in all similar places?
For this one,
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
>
> Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
> ---
> kernel/kexec_internal.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
> index 2595defe8c0d..d35d9792402d 100644
> --- a/kernel/kexec_internal.h
> +++ b/kernel/kexec_internal.h
> @@ -23,7 +23,8 @@ int kimage_is_destination_range(struct kimage *image,
> extern atomic_t __kexec_lock;
> static inline bool kexec_trylock(void)
> {
> - return atomic_cmpxchg_acquire(&__kexec_lock, 0, 1) == 0;
> + int old = 0;
> + return atomic_try_cmpxchg_acquire(&__kexec_lock, &old, 1);
> }
> static inline void kexec_unlock(void)
> {
> --
> 2.42.0
>
>
> _______________________________________________
> kexec mailing list
> kexec@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/kexec
>
_______________________________________________
kexec mailing list
kexec@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/kexec
