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1da177e4 LT |
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. */ | |
25 | int 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 | */ | |
37 | struct task_struct *__stop_machine_run(int (*fn)(void *), void *data, | |
38 | unsigned int cpu); | |
39 | ||
40 | #else | |
41 | ||
42 | static 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 */ |