Viewing file:  stop_machine.h (1.76 KB) -rw-r--r--
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#ifndef _LINUX_STOP_MACHINE
#define _LINUX_STOP_MACHINE
/* "Bogolock": stop the entire machine, disable interrupts. This is a
very heavy lock, which is equivalent to grabbing every spinlock
(and more). So the "read" side to such a lock is anything which
diables preeempt. */
#include <linux/cpu.h>
#include <asm/system.h>
#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
/**
* stop_machine_run: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn()
* @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
*
* Description: This causes a thread to be scheduled on every other cpu,
* each of which disables interrupts, and finally interrupts are disabled
* on the current CPU. The result is that noone is holding a spinlock
* or inside any other preempt-disabled region when @fn() runs.
*
* This can be thought of as a very heavy write lock, equivalent to
* grabbing every spinlock in the kernel. */
int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
/**
* __stop_machine_run: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn
* @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
*
* Description: This is a special version of the above, which returns the
* thread which has run @fn(): kthread_stop will return the return value
* of @fn(). Used by hotplug cpu.
*/
struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
unsigned int cpu);
#else
static inline int stop_machine_run(int (*fn)(void *), void *data,
unsigned int cpu)
{
int ret;
local_irq_disable();
ret = fn(data);
local_irq_enable();
return ret;
}
#endif /* CONFIG_SMP */
#endif /* _LINUX_STOP_MACHINE */
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