Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (e3b59518) · Commits · 戴 / test

Pull irq fixes and cleanups from Thomas Gleixner: "Commit ("nohz: Make tick_nohz_irq_exit() irq safe") is the first commit in the series and the minimal necessary bugfix, which needs to go back into stable. The remanining commits enforce irq disabling in irq_exit(), sanitize the hardirq/softirq preempt count transition and remove a bunch of no longer necessary conditionals." I personally love getting rid of the very subtle and confusing IRQ_EXIT_OFFSET thing. Even apart from the whole "more lines removed than added" thing. * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irq: Don't re-enable interrupts at the end of irq_exit irq: Remove IRQ_EXIT_OFFSET workaround Revert "nohz: Make tick_nohz_irq_exit() irq safe" irq: Sanitize invoke_softirq irq: Ensure irq_exit() code runs with interrupts disabled nohz: Make tick_nohz_irq_exit() irq safe

include/linux/hardirq.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -118,10 +118,8 @@

		#ifdef CONFIG_PREEMPT_COUNT
		# define preemptible() (preempt_count() == 0 && !irqs_disabled())
		# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
		#else
		# define preemptible() 0
		# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
		#endif

		#if defined(CONFIG_SMP) \|\| defined(CONFIG_GENERIC_HARDIRQS)

kernel/softirq.c

+9 −12

Original line number	Diff line number	Diff line
		@@ -323,18 +323,10 @@ void irq_enter(void)

		static inline void invoke_softirq(void)
		{
		if (!force_irqthreads) {
		#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
		if (!force_irqthreads)
		__do_softirq();
		#else
		do_softirq();
		#endif
		} else {
		__local_bh_disable((unsigned long)__builtin_return_address(0),
		SOFTIRQ_OFFSET);
		else
		wakeup_softirqd();
		__local_bh_enable(SOFTIRQ_OFFSET);
		}
		}

		/*
		@@ -342,9 +334,15 @@ static inline void invoke_softirq(void)
		*/
		void irq_exit(void)
		{
		#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
		local_irq_disable();
		#else
		WARN_ON_ONCE(!irqs_disabled());
		#endif

		account_irq_exit_time(current);
		trace_hardirq_exit();
		sub_preempt_count(IRQ_EXIT_OFFSET);
		sub_preempt_count(HARDIRQ_OFFSET);
		if (!in_interrupt() && local_softirq_pending())
		invoke_softirq();

		@@ -354,7 +352,6 @@ void irq_exit(void)
		tick_nohz_irq_exit();
		#endif
		rcu_irq_exit();
		sched_preempt_enable_no_resched();
		}

		/*

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