include/linux/stop_machine.h

   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    disables preeempt. */
   7 #include <linux/cpu.h>
   8 #include <linux/cpumask.h>
   9 #include <asm/system.h>
  10
  11 #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
  12
  13 /**
  14  * stop_machine: freeze the machine on all CPUs and run this function
  15  * @fn: the function to run
  16  * @data: the data ptr for the @fn()
  17  * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
  18  *
  19  * Description: This causes a thread to be scheduled on every cpu,
  20  * each of which disables interrupts.  The result is that noone is
  21  * holding a spinlock or inside any other preempt-disabled region when
  22  * @fn() runs.
  23  *
  24  * This can be thought of as a very heavy write lock, equivalent to
  25  * grabbing every spinlock in the kernel. */
  26 int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
  27
  28 /**
  29  * __stop_machine: freeze the machine on all CPUs and run this function
  30  * @fn: the function to run
  31  * @data: the data ptr for the @fn
  32  * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
  33  *
  34  * Description: This is a special version of the above, which assumes cpus
  35  * won't come or go while it's being called.  Used by hotplug cpu.
  36  */
  37 int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
  38 #else
  39
  40 static inline int stop_machine(int (*fn)(void *), void *data,
  41                                const cpumask_t *cpus)
  42 {
  43         int ret;
  44         local_irq_disable();
  45         ret = fn(data);
  46         local_irq_enable();
  47         return ret;
  48 }
  49 #endif /* CONFIG_SMP */
  50 #endif /* _LINUX_STOP_MACHINE */