Linux kernel mirror (for testing)
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linux
1#ifndef _LINUX_STOP_MACHINE
2#define _LINUX_STOP_MACHINE
3/* "Bogolock": stop the entire machine, disable interrupts. This is a
4 very heavy lock, which is equivalent to grabbing every spinlock
5 (and more). So the "read" side to such a lock is anything which
6 diables preeempt. */
7#include <linux/config.h>
8#include <linux/cpu.h>
9#include <asm/system.h>
10
11#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
12/**
13 * stop_machine_run: freeze the machine on all CPUs and run this function
14 * @fn: the function to run
15 * @data: the data ptr for the @fn()
16 * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
17 *
18 * Description: This causes a thread to be scheduled on every other cpu,
19 * each of which disables interrupts, and finally interrupts are disabled
20 * on the current CPU. The result is that noone is holding a spinlock
21 * or inside any other preempt-disabled region when @fn() runs.
22 *
23 * This can be thought of as a very heavy write lock, equivalent to
24 * grabbing every spinlock in the kernel. */
25int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
26
27/**
28 * __stop_machine_run: freeze the machine on all CPUs and run this function
29 * @fn: the function to run
30 * @data: the data ptr for the @fn
31 * @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
32 *
33 * Description: This is a special version of the above, which returns the
34 * thread which has run @fn(): kthread_stop will return the return value
35 * of @fn(). Used by hotplug cpu.
36 */
37struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
38 unsigned int cpu);
39
40#else
41
42static inline int stop_machine_run(int (*fn)(void *), void *data,
43 unsigned int cpu)
44{
45 int ret;
46 local_irq_disable();
47 ret = fn(data);
48 local_irq_enable();
49 return ret;
50}
51#endif /* CONFIG_SMP */
52#endif /* _LINUX_STOP_MACHINE */