cpu/hotplug: Remove cpu_report_state() and related unused cruft (5356297d) · Commits · EulixOS / Software / Kernel

include/linux/cpu.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -184,8 +184,6 @@ void arch_cpu_idle_enter(void);
		void arch_cpu_idle_exit(void);
		void __noreturn arch_cpu_idle_dead(void);

		int cpu_report_state(int cpu);
		int cpu_check_up_prepare(int cpu);
		void cpu_set_state_online(int cpu);
		void play_idle_precise(u64 duration_ns, u64 latency_ns);

kernel/smpboot.c

+0 −90

Original line number	Diff line number	Diff line
		@@ -329,97 +329,7 @@ EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
		#ifndef CONFIG_HOTPLUG_CORE_SYNC
		static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD);

		/*
		* Called to poll specified CPU's state, for example, when waiting for
		* a CPU to come online.
		*/
		int cpu_report_state(int cpu)
		{
		return atomic_read(&per_cpu(cpu_hotplug_state, cpu));
		}

		/*
		* If CPU has died properly, set its state to CPU_UP_PREPARE and
		* return success. Otherwise, return -EBUSY if the CPU died after
		* cpu_wait_death() timed out. And yet otherwise again, return -EAGAIN
		* if cpu_wait_death() timed out and the CPU still hasn't gotten around
		* to dying. In the latter two cases, the CPU might not be set up
		* properly, but it is up to the arch-specific code to decide.
		* Finally, -EIO indicates an unanticipated problem.
		*
		* Note that it is permissible to omit this call entirely, as is
		* done in architectures that do no CPU-hotplug error checking.
		*/
		int cpu_check_up_prepare(int cpu)
		{
		if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
		return 0;
		}

		switch (atomic_read(&per_cpu(cpu_hotplug_state, cpu))) {

		case CPU_POST_DEAD:

		/* The CPU died properly, so just start it up again. */
		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
		return 0;

		case CPU_DEAD_FROZEN:

		/*
		* Timeout during CPU death, so let caller know.
		* The outgoing CPU completed its processing, but after
		* cpu_wait_death() timed out and reported the error. The
		* caller is free to proceed, in which case the state
		* will be reset properly by cpu_set_state_online().
		* Proceeding despite this -EBUSY return makes sense
		* for systems where the outgoing CPUs take themselves
		* offline, with no post-death manipulation required from
		* a surviving CPU.
		*/
		return -EBUSY;

		case CPU_BROKEN:

		/*
		* The most likely reason we got here is that there was
		* a timeout during CPU death, and the outgoing CPU never
		* did complete its processing. This could happen on
		* a virtualized system if the outgoing VCPU gets preempted
		* for more than five seconds, and the user attempts to
		* immediately online that same CPU. Trying again later
		* might return -EBUSY above, hence -EAGAIN.
		*/
		return -EAGAIN;

		case CPU_UP_PREPARE:
		/*
		* Timeout while waiting for the CPU to show up. Allow to try
		* again later.
		*/
		return 0;

		default:

		/* Should not happen. Famous last words. */
		return -EIO;
		}
		}

		/*
		* Mark the specified CPU online.
		*
		* Note that it is permissible to omit this call entirely, as is
		* done in architectures that do no CPU-hotplug error checking.
		*/
		void cpu_set_state_online(int cpu)
		{
		(void)atomic_xchg(&per_cpu(cpu_hotplug_state, cpu), CPU_ONLINE);
		}

		#ifdef CONFIG_HOTPLUG_CPU

		/*
		* Wait for the specified CPU to exit the idle loop and die.
		*/