Re: [PATCH 05/24] irq & spin_lock: Add counted interrupt disabling/enabling

On Fri, Jul 31, 2026 at 01:30:06PM -0700, Boqun Feng wrote:
> +static inline void local_interrupt_disable(void)
> +{
> +	unsigned long flags;
> +	int new_count;
> +
> +	WARN_ON_ONCE(in_nmi());
> +
> +	new_count = hardirq_disable_enter();
> +
> +	/* Interrupts can happen here, but it's OK, see __irq_exit_rcu(). */
> +
> +	if ((new_count & HARDIRQ_DISABLE_MASK) == HARDIRQ_DISABLE_OFFSET) {
> +		local_irq_save(flags);
> +		raw_cpu_write(local_interrupt_disable_state.flags, flags);
> +	}
> +}
> +
> +static inline void local_interrupt_enable(void)
> +{
> +	int new_count;
> +
> +	new_count = hardirq_disable_exit();
> +
> +	if ((new_count & HARDIRQ_DISABLE_MASK) == 0) {
> +		unsigned long flags;
> +
> +		flags = raw_cpu_read(local_interrupt_disable_state.flags);
> +		local_irq_restore(flags);
> +		/*
> +		 * TODO: re-read preempt count can be avoided, but it needs
> +		 * should_resched() taking another parameter as the current
> +		 * preempt count
> +		 */
> +#ifdef CONFIG_PREEMPTION
> +		if (should_resched(0))
> +			__preempt_schedule();

I'm confused by this one. This should not be needed. If there was a
preemption while IRQs were disabled, there should be a pending
IPI.

Notably local_irq_restore() also doesn't do this, since otherwise you
would not have needed to add this here, since you already call that.

> +#endif
> +	}
> +}