From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- include/linux/stop_machine.h | 52 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 include/linux/stop_machine.h (limited to 'include/linux/stop_machine.h') diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h new file mode 100644 index 000000000000..151a803ed0ed --- /dev/null +++ b/include/linux/stop_machine.h @@ -0,0 +1,52 @@ +#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 +#include +#include + +#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 */ -- cgit