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 | */ | |
3c829c36 | 68 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
69 | static void __local_bh_disable(unsigned long ip) |
70 | { | |
71 | unsigned long flags; | |
72 | ||
73 | WARN_ON_ONCE(in_irq()); | |
74 | ||
75 | raw_local_irq_save(flags); | |
76 | add_preempt_count(SOFTIRQ_OFFSET); | |
77 | /* | |
78 | * Were softirqs turned off above: | |
79 | */ | |
80 | if (softirq_count() == SOFTIRQ_OFFSET) | |
81 | trace_softirqs_off(ip); | |
82 | raw_local_irq_restore(flags); | |
83 | } | |
3c829c36 TC |
84 | #else /* !CONFIG_TRACE_IRQFLAGS */ |
85 | static inline void __local_bh_disable(unsigned long ip) | |
86 | { | |
87 | add_preempt_count(SOFTIRQ_OFFSET); | |
88 | barrier(); | |
89 | } | |
90 | #endif /* CONFIG_TRACE_IRQFLAGS */ | |
de30a2b3 IM |
91 | |
92 | void local_bh_disable(void) | |
93 | { | |
94 | __local_bh_disable((unsigned long)__builtin_return_address(0)); | |
95 | } | |
96 | ||
97 | EXPORT_SYMBOL(local_bh_disable); | |
98 | ||
99 | void __local_bh_enable(void) | |
100 | { | |
101 | WARN_ON_ONCE(in_irq()); | |
102 | ||
103 | /* | |
104 | * softirqs should never be enabled by __local_bh_enable(), | |
105 | * it always nests inside local_bh_enable() sections: | |
106 | */ | |
107 | WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET); | |
108 | ||
109 | sub_preempt_count(SOFTIRQ_OFFSET); | |
110 | } | |
111 | EXPORT_SYMBOL_GPL(__local_bh_enable); | |
112 | ||
113 | /* | |
114 | * Special-case - softirqs can safely be enabled in | |
115 | * cond_resched_softirq(), or by __do_softirq(), | |
116 | * without processing still-pending softirqs: | |
117 | */ | |
118 | void _local_bh_enable(void) | |
119 | { | |
120 | WARN_ON_ONCE(in_irq()); | |
121 | WARN_ON_ONCE(!irqs_disabled()); | |
122 | ||
123 | if (softirq_count() == SOFTIRQ_OFFSET) | |
124 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
125 | sub_preempt_count(SOFTIRQ_OFFSET); | |
126 | } | |
127 | ||
128 | EXPORT_SYMBOL(_local_bh_enable); | |
129 | ||
130 | void local_bh_enable(void) | |
131 | { | |
3c829c36 | 132 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
133 | unsigned long flags; |
134 | ||
135 | WARN_ON_ONCE(in_irq()); | |
3c829c36 | 136 | #endif |
de30a2b3 IM |
137 | WARN_ON_ONCE(irqs_disabled()); |
138 | ||
3c829c36 | 139 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 140 | local_irq_save(flags); |
3c829c36 | 141 | #endif |
de30a2b3 IM |
142 | /* |
143 | * Are softirqs going to be turned on now: | |
144 | */ | |
145 | if (softirq_count() == SOFTIRQ_OFFSET) | |
146 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
147 | /* | |
148 | * Keep preemption disabled until we are done with | |
149 | * softirq processing: | |
150 | */ | |
151 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
152 | ||
153 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
154 | do_softirq(); | |
155 | ||
156 | dec_preempt_count(); | |
3c829c36 | 157 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 158 | local_irq_restore(flags); |
3c829c36 | 159 | #endif |
de30a2b3 IM |
160 | preempt_check_resched(); |
161 | } | |
162 | EXPORT_SYMBOL(local_bh_enable); | |
163 | ||
164 | void local_bh_enable_ip(unsigned long ip) | |
165 | { | |
3c829c36 | 166 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
167 | unsigned long flags; |
168 | ||
169 | WARN_ON_ONCE(in_irq()); | |
170 | ||
171 | local_irq_save(flags); | |
3c829c36 | 172 | #endif |
de30a2b3 IM |
173 | /* |
174 | * Are softirqs going to be turned on now: | |
175 | */ | |
176 | if (softirq_count() == SOFTIRQ_OFFSET) | |
177 | trace_softirqs_on(ip); | |
178 | /* | |
179 | * Keep preemption disabled until we are done with | |
180 | * softirq processing: | |
181 | */ | |
182 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
183 | ||
184 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
185 | do_softirq(); | |
186 | ||
187 | dec_preempt_count(); | |
3c829c36 | 188 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 189 | local_irq_restore(flags); |
3c829c36 | 190 | #endif |
de30a2b3 IM |
191 | preempt_check_resched(); |
192 | } | |
193 | EXPORT_SYMBOL(local_bh_enable_ip); | |
194 | ||
1da177e4 LT |
195 | /* |
196 | * We restart softirq processing MAX_SOFTIRQ_RESTART times, | |
197 | * and we fall back to softirqd after that. | |
198 | * | |
199 | * This number has been established via experimentation. | |
200 | * The two things to balance is latency against fairness - | |
201 | * we want to handle softirqs as soon as possible, but they | |
202 | * should not be able to lock up the box. | |
203 | */ | |
204 | #define MAX_SOFTIRQ_RESTART 10 | |
205 | ||
206 | asmlinkage void __do_softirq(void) | |
207 | { | |
208 | struct softirq_action *h; | |
209 | __u32 pending; | |
210 | int max_restart = MAX_SOFTIRQ_RESTART; | |
211 | int cpu; | |
212 | ||
213 | pending = local_softirq_pending(); | |
829035fd PM |
214 | account_system_vtime(current); |
215 | ||
de30a2b3 IM |
216 | __local_bh_disable((unsigned long)__builtin_return_address(0)); |
217 | trace_softirq_enter(); | |
1da177e4 | 218 | |
1da177e4 LT |
219 | cpu = smp_processor_id(); |
220 | restart: | |
221 | /* Reset the pending bitmask before enabling irqs */ | |
3f74478b | 222 | set_softirq_pending(0); |
1da177e4 | 223 | |
c70f5d66 | 224 | local_irq_enable(); |
1da177e4 LT |
225 | |
226 | h = softirq_vec; | |
227 | ||
228 | do { | |
229 | if (pending & 1) { | |
230 | h->action(h); | |
231 | rcu_bh_qsctr_inc(cpu); | |
232 | } | |
233 | h++; | |
234 | pending >>= 1; | |
235 | } while (pending); | |
236 | ||
c70f5d66 | 237 | local_irq_disable(); |
1da177e4 LT |
238 | |
239 | pending = local_softirq_pending(); | |
240 | if (pending && --max_restart) | |
241 | goto restart; | |
242 | ||
243 | if (pending) | |
244 | wakeup_softirqd(); | |
245 | ||
de30a2b3 | 246 | trace_softirq_exit(); |
829035fd PM |
247 | |
248 | account_system_vtime(current); | |
de30a2b3 | 249 | _local_bh_enable(); |
1da177e4 LT |
250 | } |
251 | ||
252 | #ifndef __ARCH_HAS_DO_SOFTIRQ | |
253 | ||
254 | asmlinkage void do_softirq(void) | |
255 | { | |
256 | __u32 pending; | |
257 | unsigned long flags; | |
258 | ||
259 | if (in_interrupt()) | |
260 | return; | |
261 | ||
262 | local_irq_save(flags); | |
263 | ||
264 | pending = local_softirq_pending(); | |
265 | ||
266 | if (pending) | |
267 | __do_softirq(); | |
268 | ||
269 | local_irq_restore(flags); | |
270 | } | |
271 | ||
272 | EXPORT_SYMBOL(do_softirq); | |
273 | ||
274 | #endif | |
275 | ||
dde4b2b5 IM |
276 | /* |
277 | * Enter an interrupt context. | |
278 | */ | |
279 | void irq_enter(void) | |
280 | { | |
281 | account_system_vtime(current); | |
282 | add_preempt_count(HARDIRQ_OFFSET); | |
283 | trace_hardirq_enter(); | |
284 | } | |
285 | ||
1da177e4 LT |
286 | #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED |
287 | # define invoke_softirq() __do_softirq() | |
288 | #else | |
289 | # define invoke_softirq() do_softirq() | |
290 | #endif | |
291 | ||
292 | /* | |
293 | * Exit an interrupt context. Process softirqs if needed and possible: | |
294 | */ | |
295 | void irq_exit(void) | |
296 | { | |
297 | account_system_vtime(current); | |
de30a2b3 | 298 | trace_hardirq_exit(); |
1da177e4 LT |
299 | sub_preempt_count(IRQ_EXIT_OFFSET); |
300 | if (!in_interrupt() && local_softirq_pending()) | |
301 | invoke_softirq(); | |
302 | preempt_enable_no_resched(); | |
303 | } | |
304 | ||
305 | /* | |
306 | * This function must run with irqs disabled! | |
307 | */ | |
308 | inline fastcall void raise_softirq_irqoff(unsigned int nr) | |
309 | { | |
310 | __raise_softirq_irqoff(nr); | |
311 | ||
312 | /* | |
313 | * If we're in an interrupt or softirq, we're done | |
314 | * (this also catches softirq-disabled code). We will | |
315 | * actually run the softirq once we return from | |
316 | * the irq or softirq. | |
317 | * | |
318 | * Otherwise we wake up ksoftirqd to make sure we | |
319 | * schedule the softirq soon. | |
320 | */ | |
321 | if (!in_interrupt()) | |
322 | wakeup_softirqd(); | |
323 | } | |
324 | ||
325 | EXPORT_SYMBOL(raise_softirq_irqoff); | |
326 | ||
327 | void fastcall raise_softirq(unsigned int nr) | |
328 | { | |
329 | unsigned long flags; | |
330 | ||
331 | local_irq_save(flags); | |
332 | raise_softirq_irqoff(nr); | |
333 | local_irq_restore(flags); | |
334 | } | |
335 | ||
336 | void open_softirq(int nr, void (*action)(struct softirq_action*), void *data) | |
337 | { | |
338 | softirq_vec[nr].data = data; | |
339 | softirq_vec[nr].action = action; | |
340 | } | |
341 | ||
1da177e4 LT |
342 | /* Tasklets */ |
343 | struct tasklet_head | |
344 | { | |
345 | struct tasklet_struct *list; | |
346 | }; | |
347 | ||
348 | /* Some compilers disobey section attribute on statics when not | |
349 | initialized -- RR */ | |
350 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL }; | |
351 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL }; | |
352 | ||
353 | void fastcall __tasklet_schedule(struct tasklet_struct *t) | |
354 | { | |
355 | unsigned long flags; | |
356 | ||
357 | local_irq_save(flags); | |
358 | t->next = __get_cpu_var(tasklet_vec).list; | |
359 | __get_cpu_var(tasklet_vec).list = t; | |
360 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
361 | local_irq_restore(flags); | |
362 | } | |
363 | ||
364 | EXPORT_SYMBOL(__tasklet_schedule); | |
365 | ||
366 | void fastcall __tasklet_hi_schedule(struct tasklet_struct *t) | |
367 | { | |
368 | unsigned long flags; | |
369 | ||
370 | local_irq_save(flags); | |
371 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
372 | __get_cpu_var(tasklet_hi_vec).list = t; | |
373 | raise_softirq_irqoff(HI_SOFTIRQ); | |
374 | local_irq_restore(flags); | |
375 | } | |
376 | ||
377 | EXPORT_SYMBOL(__tasklet_hi_schedule); | |
378 | ||
379 | static void tasklet_action(struct softirq_action *a) | |
380 | { | |
381 | struct tasklet_struct *list; | |
382 | ||
383 | local_irq_disable(); | |
384 | list = __get_cpu_var(tasklet_vec).list; | |
385 | __get_cpu_var(tasklet_vec).list = NULL; | |
386 | local_irq_enable(); | |
387 | ||
388 | while (list) { | |
389 | struct tasklet_struct *t = list; | |
390 | ||
391 | list = list->next; | |
392 | ||
393 | if (tasklet_trylock(t)) { | |
394 | if (!atomic_read(&t->count)) { | |
395 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
396 | BUG(); | |
397 | t->func(t->data); | |
398 | tasklet_unlock(t); | |
399 | continue; | |
400 | } | |
401 | tasklet_unlock(t); | |
402 | } | |
403 | ||
404 | local_irq_disable(); | |
405 | t->next = __get_cpu_var(tasklet_vec).list; | |
406 | __get_cpu_var(tasklet_vec).list = t; | |
407 | __raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
408 | local_irq_enable(); | |
409 | } | |
410 | } | |
411 | ||
412 | static void tasklet_hi_action(struct softirq_action *a) | |
413 | { | |
414 | struct tasklet_struct *list; | |
415 | ||
416 | local_irq_disable(); | |
417 | list = __get_cpu_var(tasklet_hi_vec).list; | |
418 | __get_cpu_var(tasklet_hi_vec).list = NULL; | |
419 | local_irq_enable(); | |
420 | ||
421 | while (list) { | |
422 | struct tasklet_struct *t = list; | |
423 | ||
424 | list = list->next; | |
425 | ||
426 | if (tasklet_trylock(t)) { | |
427 | if (!atomic_read(&t->count)) { | |
428 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
429 | BUG(); | |
430 | t->func(t->data); | |
431 | tasklet_unlock(t); | |
432 | continue; | |
433 | } | |
434 | tasklet_unlock(t); | |
435 | } | |
436 | ||
437 | local_irq_disable(); | |
438 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
439 | __get_cpu_var(tasklet_hi_vec).list = t; | |
440 | __raise_softirq_irqoff(HI_SOFTIRQ); | |
441 | local_irq_enable(); | |
442 | } | |
443 | } | |
444 | ||
445 | ||
446 | void tasklet_init(struct tasklet_struct *t, | |
447 | void (*func)(unsigned long), unsigned long data) | |
448 | { | |
449 | t->next = NULL; | |
450 | t->state = 0; | |
451 | atomic_set(&t->count, 0); | |
452 | t->func = func; | |
453 | t->data = data; | |
454 | } | |
455 | ||
456 | EXPORT_SYMBOL(tasklet_init); | |
457 | ||
458 | void tasklet_kill(struct tasklet_struct *t) | |
459 | { | |
460 | if (in_interrupt()) | |
461 | printk("Attempt to kill tasklet from interrupt\n"); | |
462 | ||
463 | while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { | |
464 | do | |
465 | yield(); | |
466 | while (test_bit(TASKLET_STATE_SCHED, &t->state)); | |
467 | } | |
468 | tasklet_unlock_wait(t); | |
469 | clear_bit(TASKLET_STATE_SCHED, &t->state); | |
470 | } | |
471 | ||
472 | EXPORT_SYMBOL(tasklet_kill); | |
473 | ||
474 | void __init softirq_init(void) | |
475 | { | |
476 | open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); | |
477 | open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); | |
478 | } | |
479 | ||
480 | static int ksoftirqd(void * __bind_cpu) | |
481 | { | |
482 | set_user_nice(current, 19); | |
483 | current->flags |= PF_NOFREEZE; | |
484 | ||
485 | set_current_state(TASK_INTERRUPTIBLE); | |
486 | ||
487 | while (!kthread_should_stop()) { | |
488 | preempt_disable(); | |
489 | if (!local_softirq_pending()) { | |
490 | preempt_enable_no_resched(); | |
491 | schedule(); | |
492 | preempt_disable(); | |
493 | } | |
494 | ||
495 | __set_current_state(TASK_RUNNING); | |
496 | ||
497 | while (local_softirq_pending()) { | |
498 | /* Preempt disable stops cpu going offline. | |
499 | If already offline, we'll be on wrong CPU: | |
500 | don't process */ | |
501 | if (cpu_is_offline((long)__bind_cpu)) | |
502 | goto wait_to_die; | |
503 | do_softirq(); | |
504 | preempt_enable_no_resched(); | |
505 | cond_resched(); | |
506 | preempt_disable(); | |
507 | } | |
508 | preempt_enable(); | |
509 | set_current_state(TASK_INTERRUPTIBLE); | |
510 | } | |
511 | __set_current_state(TASK_RUNNING); | |
512 | return 0; | |
513 | ||
514 | wait_to_die: | |
515 | preempt_enable(); | |
516 | /* Wait for kthread_stop */ | |
517 | set_current_state(TASK_INTERRUPTIBLE); | |
518 | while (!kthread_should_stop()) { | |
519 | schedule(); | |
520 | set_current_state(TASK_INTERRUPTIBLE); | |
521 | } | |
522 | __set_current_state(TASK_RUNNING); | |
523 | return 0; | |
524 | } | |
525 | ||
526 | #ifdef CONFIG_HOTPLUG_CPU | |
527 | /* | |
528 | * tasklet_kill_immediate is called to remove a tasklet which can already be | |
529 | * scheduled for execution on @cpu. | |
530 | * | |
531 | * Unlike tasklet_kill, this function removes the tasklet | |
532 | * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. | |
533 | * | |
534 | * When this function is called, @cpu must be in the CPU_DEAD state. | |
535 | */ | |
536 | void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) | |
537 | { | |
538 | struct tasklet_struct **i; | |
539 | ||
540 | BUG_ON(cpu_online(cpu)); | |
541 | BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); | |
542 | ||
543 | if (!test_bit(TASKLET_STATE_SCHED, &t->state)) | |
544 | return; | |
545 | ||
546 | /* CPU is dead, so no lock needed. */ | |
547 | for (i = &per_cpu(tasklet_vec, cpu).list; *i; i = &(*i)->next) { | |
548 | if (*i == t) { | |
549 | *i = t->next; | |
550 | return; | |
551 | } | |
552 | } | |
553 | BUG(); | |
554 | } | |
555 | ||
556 | static void takeover_tasklets(unsigned int cpu) | |
557 | { | |
558 | struct tasklet_struct **i; | |
559 | ||
560 | /* CPU is dead, so no lock needed. */ | |
561 | local_irq_disable(); | |
562 | ||
563 | /* Find end, append list for that CPU. */ | |
564 | for (i = &__get_cpu_var(tasklet_vec).list; *i; i = &(*i)->next); | |
565 | *i = per_cpu(tasklet_vec, cpu).list; | |
566 | per_cpu(tasklet_vec, cpu).list = NULL; | |
567 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
568 | ||
569 | for (i = &__get_cpu_var(tasklet_hi_vec).list; *i; i = &(*i)->next); | |
570 | *i = per_cpu(tasklet_hi_vec, cpu).list; | |
571 | per_cpu(tasklet_hi_vec, cpu).list = NULL; | |
572 | raise_softirq_irqoff(HI_SOFTIRQ); | |
573 | ||
574 | local_irq_enable(); | |
575 | } | |
576 | #endif /* CONFIG_HOTPLUG_CPU */ | |
577 | ||
8c78f307 | 578 | static int __cpuinit cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
579 | unsigned long action, |
580 | void *hcpu) | |
581 | { | |
582 | int hotcpu = (unsigned long)hcpu; | |
583 | struct task_struct *p; | |
584 | ||
585 | switch (action) { | |
586 | case CPU_UP_PREPARE: | |
1da177e4 LT |
587 | p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu); |
588 | if (IS_ERR(p)) { | |
589 | printk("ksoftirqd for %i failed\n", hotcpu); | |
590 | return NOTIFY_BAD; | |
591 | } | |
592 | kthread_bind(p, hotcpu); | |
593 | per_cpu(ksoftirqd, hotcpu) = p; | |
594 | break; | |
595 | case CPU_ONLINE: | |
596 | wake_up_process(per_cpu(ksoftirqd, hotcpu)); | |
597 | break; | |
598 | #ifdef CONFIG_HOTPLUG_CPU | |
599 | case CPU_UP_CANCELED: | |
fc75cdfa HC |
600 | if (!per_cpu(ksoftirqd, hotcpu)) |
601 | break; | |
1da177e4 | 602 | /* Unbind so it can run. Fall thru. */ |
a4c4af7c HC |
603 | kthread_bind(per_cpu(ksoftirqd, hotcpu), |
604 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
605 | case CPU_DEAD: |
606 | p = per_cpu(ksoftirqd, hotcpu); | |
607 | per_cpu(ksoftirqd, hotcpu) = NULL; | |
608 | kthread_stop(p); | |
609 | takeover_tasklets(hotcpu); | |
610 | break; | |
611 | #endif /* CONFIG_HOTPLUG_CPU */ | |
612 | } | |
613 | return NOTIFY_OK; | |
614 | } | |
615 | ||
8c78f307 | 616 | static struct notifier_block __cpuinitdata cpu_nfb = { |
1da177e4 LT |
617 | .notifier_call = cpu_callback |
618 | }; | |
619 | ||
620 | __init int spawn_ksoftirqd(void) | |
621 | { | |
622 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 AM |
623 | int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); |
624 | ||
625 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
626 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); |
627 | register_cpu_notifier(&cpu_nfb); | |
628 | return 0; | |
629 | } | |
78eef01b AM |
630 | |
631 | #ifdef CONFIG_SMP | |
632 | /* | |
633 | * Call a function on all processors | |
634 | */ | |
635 | int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait) | |
636 | { | |
637 | int ret = 0; | |
638 | ||
639 | preempt_disable(); | |
640 | ret = smp_call_function(func, info, retry, wait); | |
641 | local_irq_disable(); | |
642 | func(info); | |
643 | local_irq_enable(); | |
644 | preempt_enable(); | |
645 | return ret; | |
646 | } | |
647 | EXPORT_SYMBOL(on_each_cpu); | |
648 | #endif |