On 09/22, Waiman Long wrote:
>
> This patch is currently only active for 64-bit architectures.
Why?
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -2485,6 +2485,16 @@ void __set_current_blocked(const sigset_t *newset)
> {
> struct task_struct *tsk = current;
>
> + /*
> + * In case the signal mask hasn't changed, we won't need to take
> + * the lock. As the current blocked mask can be modified by other
> + * CPUs,
No, nobody else should modify current->blocked.
Yes, we need to cleanup the usage of force_sig_info(), and probably remove
the "struct task_struct *t" argument.
> we need to do an atomic read without lock. In other words,
> + * this check will only be done on 64-bit systems.
> + */
> +#if _NSIG_WORDS == 1
> + if (READ_ONCE(tsk->blocked.sig[0]) == newset->sig[0])
> + return;
> +#endif
OK, agreed, but this should not depend on _NSIG_WORDS == 1 and
READ_ONCE() looks confusing. It seems you need to add the new helper
into include/linux/signal.h.
Oleg.
