Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/softirq.c | |
3 | * | |
4 | * Copyright (C) 1992 Linus Torvalds | |
5 | * | |
6 | * Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903) | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/kernel_stat.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/notifier.h> | |
15 | #include <linux/percpu.h> | |
16 | #include <linux/cpu.h> | |
17 | #include <linux/kthread.h> | |
18 | #include <linux/rcupdate.h> | |
78eef01b | 19 | #include <linux/smp.h> |
1da177e4 LT |
20 | |
21 | #include <asm/irq.h> | |
22 | /* | |
23 | - No shared variables, all the data are CPU local. | |
24 | - If a softirq needs serialization, let it serialize itself | |
25 | by its own spinlocks. | |
26 | - Even if softirq is serialized, only local cpu is marked for | |
27 | execution. Hence, we get something sort of weak cpu binding. | |
28 | Though it is still not clear, will it result in better locality | |
29 | or will not. | |
30 | ||
31 | Examples: | |
32 | - NET RX softirq. It is multithreaded and does not require | |
33 | any global serialization. | |
34 | - NET TX softirq. It kicks software netdevice queues, hence | |
35 | it is logically serialized per device, but this serialization | |
36 | is invisible to common code. | |
37 | - Tasklets: serialized wrt itself. | |
38 | */ | |
39 | ||
40 | #ifndef __ARCH_IRQ_STAT | |
41 | irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned; | |
42 | EXPORT_SYMBOL(irq_stat); | |
43 | #endif | |
44 | ||
45 | static struct softirq_action softirq_vec[32] __cacheline_aligned_in_smp; | |
46 | ||
47 | static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); | |
48 | ||
49 | /* | |
50 | * we cannot loop indefinitely here to avoid userspace starvation, | |
51 | * but we also don't want to introduce a worst case 1/HZ latency | |
52 | * to the pending events, so lets the scheduler to balance | |
53 | * the softirq load for us. | |
54 | */ | |
55 | static inline void wakeup_softirqd(void) | |
56 | { | |
57 | /* Interrupts are disabled: no need to stop preemption */ | |
58 | struct task_struct *tsk = __get_cpu_var(ksoftirqd); | |
59 | ||
60 | if (tsk && tsk->state != TASK_RUNNING) | |
61 | wake_up_process(tsk); | |
62 | } | |
63 | ||
de30a2b3 IM |
64 | /* |
65 | * This one is for softirq.c-internal use, | |
66 | * where hardirqs are disabled legitimately: | |
67 | */ | |
68 | static void __local_bh_disable(unsigned long ip) | |
69 | { | |
70 | unsigned long flags; | |
71 | ||
72 | WARN_ON_ONCE(in_irq()); | |
73 | ||
74 | raw_local_irq_save(flags); | |
75 | add_preempt_count(SOFTIRQ_OFFSET); | |
76 | /* | |
77 | * Were softirqs turned off above: | |
78 | */ | |
79 | if (softirq_count() == SOFTIRQ_OFFSET) | |
80 | trace_softirqs_off(ip); | |
81 | raw_local_irq_restore(flags); | |
82 | } | |
83 | ||
84 | void local_bh_disable(void) | |
85 | { | |
86 | __local_bh_disable((unsigned long)__builtin_return_address(0)); | |
87 | } | |
88 | ||
89 | EXPORT_SYMBOL(local_bh_disable); | |
90 | ||
91 | void __local_bh_enable(void) | |
92 | { | |
93 | WARN_ON_ONCE(in_irq()); | |
94 | ||
95 | /* | |
96 | * softirqs should never be enabled by __local_bh_enable(), | |
97 | * it always nests inside local_bh_enable() sections: | |
98 | */ | |
99 | WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET); | |
100 | ||
101 | sub_preempt_count(SOFTIRQ_OFFSET); | |
102 | } | |
103 | EXPORT_SYMBOL_GPL(__local_bh_enable); | |
104 | ||
105 | /* | |
106 | * Special-case - softirqs can safely be enabled in | |
107 | * cond_resched_softirq(), or by __do_softirq(), | |
108 | * without processing still-pending softirqs: | |
109 | */ | |
110 | void _local_bh_enable(void) | |
111 | { | |
112 | WARN_ON_ONCE(in_irq()); | |
113 | WARN_ON_ONCE(!irqs_disabled()); | |
114 | ||
115 | if (softirq_count() == SOFTIRQ_OFFSET) | |
116 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
117 | sub_preempt_count(SOFTIRQ_OFFSET); | |
118 | } | |
119 | ||
120 | EXPORT_SYMBOL(_local_bh_enable); | |
121 | ||
122 | void local_bh_enable(void) | |
123 | { | |
124 | unsigned long flags; | |
125 | ||
126 | WARN_ON_ONCE(in_irq()); | |
127 | WARN_ON_ONCE(irqs_disabled()); | |
128 | ||
129 | local_irq_save(flags); | |
130 | /* | |
131 | * Are softirqs going to be turned on now: | |
132 | */ | |
133 | if (softirq_count() == SOFTIRQ_OFFSET) | |
134 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
135 | /* | |
136 | * Keep preemption disabled until we are done with | |
137 | * softirq processing: | |
138 | */ | |
139 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
140 | ||
141 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
142 | do_softirq(); | |
143 | ||
144 | dec_preempt_count(); | |
145 | local_irq_restore(flags); | |
146 | preempt_check_resched(); | |
147 | } | |
148 | EXPORT_SYMBOL(local_bh_enable); | |
149 | ||
150 | void local_bh_enable_ip(unsigned long ip) | |
151 | { | |
152 | unsigned long flags; | |
153 | ||
154 | WARN_ON_ONCE(in_irq()); | |
155 | ||
156 | local_irq_save(flags); | |
157 | /* | |
158 | * Are softirqs going to be turned on now: | |
159 | */ | |
160 | if (softirq_count() == SOFTIRQ_OFFSET) | |
161 | trace_softirqs_on(ip); | |
162 | /* | |
163 | * Keep preemption disabled until we are done with | |
164 | * softirq processing: | |
165 | */ | |
166 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
167 | ||
168 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
169 | do_softirq(); | |
170 | ||
171 | dec_preempt_count(); | |
172 | local_irq_restore(flags); | |
173 | preempt_check_resched(); | |
174 | } | |
175 | EXPORT_SYMBOL(local_bh_enable_ip); | |
176 | ||
1da177e4 LT |
177 | /* |
178 | * We restart softirq processing MAX_SOFTIRQ_RESTART times, | |
179 | * and we fall back to softirqd after that. | |
180 | * | |
181 | * This number has been established via experimentation. | |
182 | * The two things to balance is latency against fairness - | |
183 | * we want to handle softirqs as soon as possible, but they | |
184 | * should not be able to lock up the box. | |
185 | */ | |
186 | #define MAX_SOFTIRQ_RESTART 10 | |
187 | ||
188 | asmlinkage void __do_softirq(void) | |
189 | { | |
190 | struct softirq_action *h; | |
191 | __u32 pending; | |
192 | int max_restart = MAX_SOFTIRQ_RESTART; | |
193 | int cpu; | |
194 | ||
195 | pending = local_softirq_pending(); | |
829035fd PM |
196 | account_system_vtime(current); |
197 | ||
de30a2b3 IM |
198 | __local_bh_disable((unsigned long)__builtin_return_address(0)); |
199 | trace_softirq_enter(); | |
1da177e4 | 200 | |
1da177e4 LT |
201 | cpu = smp_processor_id(); |
202 | restart: | |
203 | /* Reset the pending bitmask before enabling irqs */ | |
3f74478b | 204 | set_softirq_pending(0); |
1da177e4 | 205 | |
c70f5d66 | 206 | local_irq_enable(); |
1da177e4 LT |
207 | |
208 | h = softirq_vec; | |
209 | ||
210 | do { | |
211 | if (pending & 1) { | |
212 | h->action(h); | |
213 | rcu_bh_qsctr_inc(cpu); | |
214 | } | |
215 | h++; | |
216 | pending >>= 1; | |
217 | } while (pending); | |
218 | ||
c70f5d66 | 219 | local_irq_disable(); |
1da177e4 LT |
220 | |
221 | pending = local_softirq_pending(); | |
222 | if (pending && --max_restart) | |
223 | goto restart; | |
224 | ||
225 | if (pending) | |
226 | wakeup_softirqd(); | |
227 | ||
de30a2b3 | 228 | trace_softirq_exit(); |
829035fd PM |
229 | |
230 | account_system_vtime(current); | |
de30a2b3 | 231 | _local_bh_enable(); |
1da177e4 LT |
232 | } |
233 | ||
234 | #ifndef __ARCH_HAS_DO_SOFTIRQ | |
235 | ||
236 | asmlinkage void do_softirq(void) | |
237 | { | |
238 | __u32 pending; | |
239 | unsigned long flags; | |
240 | ||
241 | if (in_interrupt()) | |
242 | return; | |
243 | ||
244 | local_irq_save(flags); | |
245 | ||
246 | pending = local_softirq_pending(); | |
247 | ||
248 | if (pending) | |
249 | __do_softirq(); | |
250 | ||
251 | local_irq_restore(flags); | |
252 | } | |
253 | ||
254 | EXPORT_SYMBOL(do_softirq); | |
255 | ||
256 | #endif | |
257 | ||
1da177e4 LT |
258 | #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED |
259 | # define invoke_softirq() __do_softirq() | |
260 | #else | |
261 | # define invoke_softirq() do_softirq() | |
262 | #endif | |
263 | ||
264 | /* | |
265 | * Exit an interrupt context. Process softirqs if needed and possible: | |
266 | */ | |
267 | void irq_exit(void) | |
268 | { | |
269 | account_system_vtime(current); | |
de30a2b3 | 270 | trace_hardirq_exit(); |
1da177e4 LT |
271 | sub_preempt_count(IRQ_EXIT_OFFSET); |
272 | if (!in_interrupt() && local_softirq_pending()) | |
273 | invoke_softirq(); | |
274 | preempt_enable_no_resched(); | |
275 | } | |
276 | ||
277 | /* | |
278 | * This function must run with irqs disabled! | |
279 | */ | |
280 | inline fastcall void raise_softirq_irqoff(unsigned int nr) | |
281 | { | |
282 | __raise_softirq_irqoff(nr); | |
283 | ||
284 | /* | |
285 | * If we're in an interrupt or softirq, we're done | |
286 | * (this also catches softirq-disabled code). We will | |
287 | * actually run the softirq once we return from | |
288 | * the irq or softirq. | |
289 | * | |
290 | * Otherwise we wake up ksoftirqd to make sure we | |
291 | * schedule the softirq soon. | |
292 | */ | |
293 | if (!in_interrupt()) | |
294 | wakeup_softirqd(); | |
295 | } | |
296 | ||
297 | EXPORT_SYMBOL(raise_softirq_irqoff); | |
298 | ||
299 | void fastcall raise_softirq(unsigned int nr) | |
300 | { | |
301 | unsigned long flags; | |
302 | ||
303 | local_irq_save(flags); | |
304 | raise_softirq_irqoff(nr); | |
305 | local_irq_restore(flags); | |
306 | } | |
307 | ||
308 | void open_softirq(int nr, void (*action)(struct softirq_action*), void *data) | |
309 | { | |
310 | softirq_vec[nr].data = data; | |
311 | softirq_vec[nr].action = action; | |
312 | } | |
313 | ||
1da177e4 LT |
314 | /* Tasklets */ |
315 | struct tasklet_head | |
316 | { | |
317 | struct tasklet_struct *list; | |
318 | }; | |
319 | ||
320 | /* Some compilers disobey section attribute on statics when not | |
321 | initialized -- RR */ | |
322 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL }; | |
323 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL }; | |
324 | ||
325 | void fastcall __tasklet_schedule(struct tasklet_struct *t) | |
326 | { | |
327 | unsigned long flags; | |
328 | ||
329 | local_irq_save(flags); | |
330 | t->next = __get_cpu_var(tasklet_vec).list; | |
331 | __get_cpu_var(tasklet_vec).list = t; | |
332 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
333 | local_irq_restore(flags); | |
334 | } | |
335 | ||
336 | EXPORT_SYMBOL(__tasklet_schedule); | |
337 | ||
338 | void fastcall __tasklet_hi_schedule(struct tasklet_struct *t) | |
339 | { | |
340 | unsigned long flags; | |
341 | ||
342 | local_irq_save(flags); | |
343 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
344 | __get_cpu_var(tasklet_hi_vec).list = t; | |
345 | raise_softirq_irqoff(HI_SOFTIRQ); | |
346 | local_irq_restore(flags); | |
347 | } | |
348 | ||
349 | EXPORT_SYMBOL(__tasklet_hi_schedule); | |
350 | ||
351 | static void tasklet_action(struct softirq_action *a) | |
352 | { | |
353 | struct tasklet_struct *list; | |
354 | ||
355 | local_irq_disable(); | |
356 | list = __get_cpu_var(tasklet_vec).list; | |
357 | __get_cpu_var(tasklet_vec).list = NULL; | |
358 | local_irq_enable(); | |
359 | ||
360 | while (list) { | |
361 | struct tasklet_struct *t = list; | |
362 | ||
363 | list = list->next; | |
364 | ||
365 | if (tasklet_trylock(t)) { | |
366 | if (!atomic_read(&t->count)) { | |
367 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
368 | BUG(); | |
369 | t->func(t->data); | |
370 | tasklet_unlock(t); | |
371 | continue; | |
372 | } | |
373 | tasklet_unlock(t); | |
374 | } | |
375 | ||
376 | local_irq_disable(); | |
377 | t->next = __get_cpu_var(tasklet_vec).list; | |
378 | __get_cpu_var(tasklet_vec).list = t; | |
379 | __raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
380 | local_irq_enable(); | |
381 | } | |
382 | } | |
383 | ||
384 | static void tasklet_hi_action(struct softirq_action *a) | |
385 | { | |
386 | struct tasklet_struct *list; | |
387 | ||
388 | local_irq_disable(); | |
389 | list = __get_cpu_var(tasklet_hi_vec).list; | |
390 | __get_cpu_var(tasklet_hi_vec).list = NULL; | |
391 | local_irq_enable(); | |
392 | ||
393 | while (list) { | |
394 | struct tasklet_struct *t = list; | |
395 | ||
396 | list = list->next; | |
397 | ||
398 | if (tasklet_trylock(t)) { | |
399 | if (!atomic_read(&t->count)) { | |
400 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
401 | BUG(); | |
402 | t->func(t->data); | |
403 | tasklet_unlock(t); | |
404 | continue; | |
405 | } | |
406 | tasklet_unlock(t); | |
407 | } | |
408 | ||
409 | local_irq_disable(); | |
410 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
411 | __get_cpu_var(tasklet_hi_vec).list = t; | |
412 | __raise_softirq_irqoff(HI_SOFTIRQ); | |
413 | local_irq_enable(); | |
414 | } | |
415 | } | |
416 | ||
417 | ||
418 | void tasklet_init(struct tasklet_struct *t, | |
419 | void (*func)(unsigned long), unsigned long data) | |
420 | { | |
421 | t->next = NULL; | |
422 | t->state = 0; | |
423 | atomic_set(&t->count, 0); | |
424 | t->func = func; | |
425 | t->data = data; | |
426 | } | |
427 | ||
428 | EXPORT_SYMBOL(tasklet_init); | |
429 | ||
430 | void tasklet_kill(struct tasklet_struct *t) | |
431 | { | |
432 | if (in_interrupt()) | |
433 | printk("Attempt to kill tasklet from interrupt\n"); | |
434 | ||
435 | while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { | |
436 | do | |
437 | yield(); | |
438 | while (test_bit(TASKLET_STATE_SCHED, &t->state)); | |
439 | } | |
440 | tasklet_unlock_wait(t); | |
441 | clear_bit(TASKLET_STATE_SCHED, &t->state); | |
442 | } | |
443 | ||
444 | EXPORT_SYMBOL(tasklet_kill); | |
445 | ||
446 | void __init softirq_init(void) | |
447 | { | |
448 | open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); | |
449 | open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); | |
450 | } | |
451 | ||
452 | static int ksoftirqd(void * __bind_cpu) | |
453 | { | |
454 | set_user_nice(current, 19); | |
455 | current->flags |= PF_NOFREEZE; | |
456 | ||
457 | set_current_state(TASK_INTERRUPTIBLE); | |
458 | ||
459 | while (!kthread_should_stop()) { | |
460 | preempt_disable(); | |
461 | if (!local_softirq_pending()) { | |
462 | preempt_enable_no_resched(); | |
463 | schedule(); | |
464 | preempt_disable(); | |
465 | } | |
466 | ||
467 | __set_current_state(TASK_RUNNING); | |
468 | ||
469 | while (local_softirq_pending()) { | |
470 | /* Preempt disable stops cpu going offline. | |
471 | If already offline, we'll be on wrong CPU: | |
472 | don't process */ | |
473 | if (cpu_is_offline((long)__bind_cpu)) | |
474 | goto wait_to_die; | |
475 | do_softirq(); | |
476 | preempt_enable_no_resched(); | |
477 | cond_resched(); | |
478 | preempt_disable(); | |
479 | } | |
480 | preempt_enable(); | |
481 | set_current_state(TASK_INTERRUPTIBLE); | |
482 | } | |
483 | __set_current_state(TASK_RUNNING); | |
484 | return 0; | |
485 | ||
486 | wait_to_die: | |
487 | preempt_enable(); | |
488 | /* Wait for kthread_stop */ | |
489 | set_current_state(TASK_INTERRUPTIBLE); | |
490 | while (!kthread_should_stop()) { | |
491 | schedule(); | |
492 | set_current_state(TASK_INTERRUPTIBLE); | |
493 | } | |
494 | __set_current_state(TASK_RUNNING); | |
495 | return 0; | |
496 | } | |
497 | ||
498 | #ifdef CONFIG_HOTPLUG_CPU | |
499 | /* | |
500 | * tasklet_kill_immediate is called to remove a tasklet which can already be | |
501 | * scheduled for execution on @cpu. | |
502 | * | |
503 | * Unlike tasklet_kill, this function removes the tasklet | |
504 | * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. | |
505 | * | |
506 | * When this function is called, @cpu must be in the CPU_DEAD state. | |
507 | */ | |
508 | void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) | |
509 | { | |
510 | struct tasklet_struct **i; | |
511 | ||
512 | BUG_ON(cpu_online(cpu)); | |
513 | BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); | |
514 | ||
515 | if (!test_bit(TASKLET_STATE_SCHED, &t->state)) | |
516 | return; | |
517 | ||
518 | /* CPU is dead, so no lock needed. */ | |
519 | for (i = &per_cpu(tasklet_vec, cpu).list; *i; i = &(*i)->next) { | |
520 | if (*i == t) { | |
521 | *i = t->next; | |
522 | return; | |
523 | } | |
524 | } | |
525 | BUG(); | |
526 | } | |
527 | ||
528 | static void takeover_tasklets(unsigned int cpu) | |
529 | { | |
530 | struct tasklet_struct **i; | |
531 | ||
532 | /* CPU is dead, so no lock needed. */ | |
533 | local_irq_disable(); | |
534 | ||
535 | /* Find end, append list for that CPU. */ | |
536 | for (i = &__get_cpu_var(tasklet_vec).list; *i; i = &(*i)->next); | |
537 | *i = per_cpu(tasklet_vec, cpu).list; | |
538 | per_cpu(tasklet_vec, cpu).list = NULL; | |
539 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
540 | ||
541 | for (i = &__get_cpu_var(tasklet_hi_vec).list; *i; i = &(*i)->next); | |
542 | *i = per_cpu(tasklet_hi_vec, cpu).list; | |
543 | per_cpu(tasklet_hi_vec, cpu).list = NULL; | |
544 | raise_softirq_irqoff(HI_SOFTIRQ); | |
545 | ||
546 | local_irq_enable(); | |
547 | } | |
548 | #endif /* CONFIG_HOTPLUG_CPU */ | |
549 | ||
8c78f307 | 550 | static int __cpuinit cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
551 | unsigned long action, |
552 | void *hcpu) | |
553 | { | |
554 | int hotcpu = (unsigned long)hcpu; | |
555 | struct task_struct *p; | |
556 | ||
557 | switch (action) { | |
558 | case CPU_UP_PREPARE: | |
559 | BUG_ON(per_cpu(tasklet_vec, hotcpu).list); | |
560 | BUG_ON(per_cpu(tasklet_hi_vec, hotcpu).list); | |
561 | p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu); | |
562 | if (IS_ERR(p)) { | |
563 | printk("ksoftirqd for %i failed\n", hotcpu); | |
564 | return NOTIFY_BAD; | |
565 | } | |
566 | kthread_bind(p, hotcpu); | |
567 | per_cpu(ksoftirqd, hotcpu) = p; | |
568 | break; | |
569 | case CPU_ONLINE: | |
570 | wake_up_process(per_cpu(ksoftirqd, hotcpu)); | |
571 | break; | |
572 | #ifdef CONFIG_HOTPLUG_CPU | |
573 | case CPU_UP_CANCELED: | |
fc75cdfa HC |
574 | if (!per_cpu(ksoftirqd, hotcpu)) |
575 | break; | |
1da177e4 | 576 | /* Unbind so it can run. Fall thru. */ |
a4c4af7c HC |
577 | kthread_bind(per_cpu(ksoftirqd, hotcpu), |
578 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
579 | case CPU_DEAD: |
580 | p = per_cpu(ksoftirqd, hotcpu); | |
581 | per_cpu(ksoftirqd, hotcpu) = NULL; | |
582 | kthread_stop(p); | |
583 | takeover_tasklets(hotcpu); | |
584 | break; | |
585 | #endif /* CONFIG_HOTPLUG_CPU */ | |
586 | } | |
587 | return NOTIFY_OK; | |
588 | } | |
589 | ||
8c78f307 | 590 | static struct notifier_block __cpuinitdata cpu_nfb = { |
1da177e4 LT |
591 | .notifier_call = cpu_callback |
592 | }; | |
593 | ||
594 | __init int spawn_ksoftirqd(void) | |
595 | { | |
596 | void *cpu = (void *)(long)smp_processor_id(); | |
597 | cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); | |
598 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); | |
599 | register_cpu_notifier(&cpu_nfb); | |
600 | return 0; | |
601 | } | |
78eef01b AM |
602 | |
603 | #ifdef CONFIG_SMP | |
604 | /* | |
605 | * Call a function on all processors | |
606 | */ | |
607 | int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait) | |
608 | { | |
609 | int ret = 0; | |
610 | ||
611 | preempt_disable(); | |
612 | ret = smp_call_function(func, info, retry, wait); | |
613 | local_irq_disable(); | |
614 | func(info); | |
615 | local_irq_enable(); | |
616 | preempt_enable(); | |
617 | return ret; | |
618 | } | |
619 | EXPORT_SYMBOL(on_each_cpu); | |
620 | #endif |