Commit | Line | Data |
---|---|---|
3d442233 JA |
1 | /* |
2 | * Generic helpers for smp ipi calls | |
3 | * | |
4 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 | |
3d442233 | 5 | */ |
3d442233 | 6 | #include <linux/rcupdate.h> |
59190f42 | 7 | #include <linux/rculist.h> |
641cd4cf | 8 | #include <linux/kernel.h> |
0b13fda1 IM |
9 | #include <linux/module.h> |
10 | #include <linux/percpu.h> | |
11 | #include <linux/init.h> | |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
3d442233 | 13 | #include <linux/smp.h> |
8969a5ed | 14 | #include <linux/cpu.h> |
3d442233 | 15 | |
351f8f8e | 16 | #ifdef CONFIG_USE_GENERIC_SMP_HELPERS |
8969a5ed PZ |
17 | static struct { |
18 | struct list_head queue; | |
9f5a5621 | 19 | raw_spinlock_t lock; |
0b13fda1 IM |
20 | } call_function __cacheline_aligned_in_smp = |
21 | { | |
22 | .queue = LIST_HEAD_INIT(call_function.queue), | |
9f5a5621 | 23 | .lock = __RAW_SPIN_LOCK_UNLOCKED(call_function.lock), |
0b13fda1 | 24 | }; |
3d442233 JA |
25 | |
26 | enum { | |
6e275637 | 27 | CSD_FLAG_LOCK = 0x01, |
3d442233 JA |
28 | }; |
29 | ||
30 | struct call_function_data { | |
0b13fda1 | 31 | struct call_single_data csd; |
54fdade1 | 32 | atomic_t refs; |
0b13fda1 | 33 | cpumask_var_t cpumask; |
3d442233 JA |
34 | }; |
35 | ||
e03bcb68 MM |
36 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); |
37 | ||
3d442233 | 38 | struct call_single_queue { |
0b13fda1 | 39 | struct list_head list; |
9f5a5621 | 40 | raw_spinlock_t lock; |
3d442233 JA |
41 | }; |
42 | ||
e03bcb68 | 43 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue); |
8969a5ed PZ |
44 | |
45 | static int | |
46 | hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
47 | { | |
48 | long cpu = (long)hcpu; | |
49 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
50 | ||
51 | switch (action) { | |
52 | case CPU_UP_PREPARE: | |
53 | case CPU_UP_PREPARE_FROZEN: | |
eaa95840 | 54 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
8969a5ed | 55 | cpu_to_node(cpu))) |
80b5184c | 56 | return notifier_from_errno(-ENOMEM); |
8969a5ed PZ |
57 | break; |
58 | ||
69dd647f | 59 | #ifdef CONFIG_HOTPLUG_CPU |
8969a5ed PZ |
60 | case CPU_UP_CANCELED: |
61 | case CPU_UP_CANCELED_FROZEN: | |
62 | ||
63 | case CPU_DEAD: | |
64 | case CPU_DEAD_FROZEN: | |
65 | free_cpumask_var(cfd->cpumask); | |
66 | break; | |
67 | #endif | |
68 | }; | |
69 | ||
70 | return NOTIFY_OK; | |
71 | } | |
72 | ||
73 | static struct notifier_block __cpuinitdata hotplug_cfd_notifier = { | |
0b13fda1 | 74 | .notifier_call = hotplug_cfd, |
8969a5ed PZ |
75 | }; |
76 | ||
7babe8db | 77 | static int __cpuinit init_call_single_data(void) |
3d442233 | 78 | { |
8969a5ed | 79 | void *cpu = (void *)(long)smp_processor_id(); |
3d442233 JA |
80 | int i; |
81 | ||
82 | for_each_possible_cpu(i) { | |
83 | struct call_single_queue *q = &per_cpu(call_single_queue, i); | |
84 | ||
9f5a5621 | 85 | raw_spin_lock_init(&q->lock); |
3d442233 JA |
86 | INIT_LIST_HEAD(&q->list); |
87 | } | |
8969a5ed PZ |
88 | |
89 | hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu); | |
90 | register_cpu_notifier(&hotplug_cfd_notifier); | |
91 | ||
7babe8db | 92 | return 0; |
3d442233 | 93 | } |
7babe8db | 94 | early_initcall(init_call_single_data); |
3d442233 | 95 | |
8969a5ed PZ |
96 | /* |
97 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
98 | * | |
0b13fda1 IM |
99 | * For non-synchronous ipi calls the csd can still be in use by the |
100 | * previous function call. For multi-cpu calls its even more interesting | |
101 | * as we'll have to ensure no other cpu is observing our csd. | |
8969a5ed | 102 | */ |
6e275637 | 103 | static void csd_lock_wait(struct call_single_data *data) |
8969a5ed PZ |
104 | { |
105 | while (data->flags & CSD_FLAG_LOCK) | |
106 | cpu_relax(); | |
6e275637 PZ |
107 | } |
108 | ||
109 | static void csd_lock(struct call_single_data *data) | |
110 | { | |
111 | csd_lock_wait(data); | |
8969a5ed PZ |
112 | data->flags = CSD_FLAG_LOCK; |
113 | ||
114 | /* | |
0b13fda1 IM |
115 | * prevent CPU from reordering the above assignment |
116 | * to ->flags with any subsequent assignments to other | |
117 | * fields of the specified call_single_data structure: | |
8969a5ed | 118 | */ |
8969a5ed PZ |
119 | smp_mb(); |
120 | } | |
121 | ||
122 | static void csd_unlock(struct call_single_data *data) | |
123 | { | |
124 | WARN_ON(!(data->flags & CSD_FLAG_LOCK)); | |
0b13fda1 | 125 | |
8969a5ed | 126 | /* |
0b13fda1 | 127 | * ensure we're all done before releasing data: |
8969a5ed PZ |
128 | */ |
129 | smp_mb(); | |
0b13fda1 | 130 | |
8969a5ed | 131 | data->flags &= ~CSD_FLAG_LOCK; |
3d442233 JA |
132 | } |
133 | ||
134 | /* | |
0b13fda1 IM |
135 | * Insert a previously allocated call_single_data element |
136 | * for execution on the given CPU. data must already have | |
137 | * ->func, ->info, and ->flags set. | |
3d442233 | 138 | */ |
6e275637 PZ |
139 | static |
140 | void generic_exec_single(int cpu, struct call_single_data *data, int wait) | |
3d442233 JA |
141 | { |
142 | struct call_single_queue *dst = &per_cpu(call_single_queue, cpu); | |
3d442233 | 143 | unsigned long flags; |
6e275637 | 144 | int ipi; |
3d442233 | 145 | |
9f5a5621 | 146 | raw_spin_lock_irqsave(&dst->lock, flags); |
3d442233 JA |
147 | ipi = list_empty(&dst->list); |
148 | list_add_tail(&data->list, &dst->list); | |
9f5a5621 | 149 | raw_spin_unlock_irqrestore(&dst->lock, flags); |
3d442233 | 150 | |
561920a0 | 151 | /* |
15d0d3b3 NP |
152 | * The list addition should be visible before sending the IPI |
153 | * handler locks the list to pull the entry off it because of | |
154 | * normal cache coherency rules implied by spinlocks. | |
155 | * | |
156 | * If IPIs can go out of order to the cache coherency protocol | |
157 | * in an architecture, sufficient synchronisation should be added | |
158 | * to arch code to make it appear to obey cache coherency WRT | |
0b13fda1 IM |
159 | * locking and barrier primitives. Generic code isn't really |
160 | * equipped to do the right thing... | |
561920a0 | 161 | */ |
3d442233 JA |
162 | if (ipi) |
163 | arch_send_call_function_single_ipi(cpu); | |
164 | ||
165 | if (wait) | |
6e275637 | 166 | csd_lock_wait(data); |
3d442233 JA |
167 | } |
168 | ||
169 | /* | |
170 | * Invoked by arch to handle an IPI for call function. Must be called with | |
171 | * interrupts disabled. | |
172 | */ | |
173 | void generic_smp_call_function_interrupt(void) | |
174 | { | |
175 | struct call_function_data *data; | |
c0f68c2f | 176 | int cpu = smp_processor_id(); |
3d442233 | 177 | |
269c861b SS |
178 | /* |
179 | * Shouldn't receive this interrupt on a cpu that is not yet online. | |
180 | */ | |
181 | WARN_ON_ONCE(!cpu_online(cpu)); | |
182 | ||
15d0d3b3 NP |
183 | /* |
184 | * Ensure entry is visible on call_function_queue after we have | |
185 | * entered the IPI. See comment in smp_call_function_many. | |
186 | * If we don't have this, then we may miss an entry on the list | |
187 | * and never get another IPI to process it. | |
188 | */ | |
189 | smp_mb(); | |
190 | ||
3d442233 | 191 | /* |
0b13fda1 IM |
192 | * It's ok to use list_for_each_rcu() here even though we may |
193 | * delete 'pos', since list_del_rcu() doesn't clear ->next | |
3d442233 | 194 | */ |
8969a5ed | 195 | list_for_each_entry_rcu(data, &call_function.queue, csd.list) { |
3d442233 | 196 | int refs; |
225c8e01 | 197 | void (*func) (void *info); |
3d442233 | 198 | |
6dc19899 AB |
199 | /* |
200 | * Since we walk the list without any locks, we might | |
201 | * see an entry that was completed, removed from the | |
202 | * list and is in the process of being reused. | |
203 | * | |
204 | * We must check that the cpu is in the cpumask before | |
205 | * checking the refs, and both must be set before | |
206 | * executing the callback on this cpu. | |
207 | */ | |
208 | ||
209 | if (!cpumask_test_cpu(cpu, data->cpumask)) | |
210 | continue; | |
211 | ||
212 | smp_rmb(); | |
213 | ||
214 | if (atomic_read(&data->refs) == 0) | |
215 | continue; | |
216 | ||
225c8e01 | 217 | func = data->csd.func; /* for later warn */ |
3d442233 JA |
218 | data->csd.func(data->csd.info); |
219 | ||
225c8e01 MM |
220 | /* |
221 | * If the cpu mask is not still set then it enabled interrupts, | |
222 | * we took another smp interrupt, and executed the function | |
223 | * twice on this cpu. In theory that copy decremented refs. | |
224 | */ | |
225 | if (!cpumask_test_and_clear_cpu(cpu, data->cpumask)) { | |
226 | WARN(1, "%pS enabled interrupts and double executed\n", | |
227 | func); | |
228 | continue; | |
229 | } | |
230 | ||
54fdade1 XG |
231 | refs = atomic_dec_return(&data->refs); |
232 | WARN_ON(refs < 0); | |
3d442233 JA |
233 | |
234 | if (refs) | |
235 | continue; | |
236 | ||
225c8e01 MM |
237 | WARN_ON(!cpumask_empty(data->cpumask)); |
238 | ||
239 | raw_spin_lock(&call_function.lock); | |
240 | list_del_rcu(&data->csd.list); | |
241 | raw_spin_unlock(&call_function.lock); | |
242 | ||
8969a5ed | 243 | csd_unlock(&data->csd); |
3d442233 | 244 | } |
3d442233 | 245 | |
3d442233 JA |
246 | } |
247 | ||
248 | /* | |
0b13fda1 IM |
249 | * Invoked by arch to handle an IPI for call function single. Must be |
250 | * called from the arch with interrupts disabled. | |
3d442233 JA |
251 | */ |
252 | void generic_smp_call_function_single_interrupt(void) | |
253 | { | |
254 | struct call_single_queue *q = &__get_cpu_var(call_single_queue); | |
15d0d3b3 | 255 | unsigned int data_flags; |
0b13fda1 | 256 | LIST_HEAD(list); |
3d442233 | 257 | |
269c861b SS |
258 | /* |
259 | * Shouldn't receive this interrupt on a cpu that is not yet online. | |
260 | */ | |
261 | WARN_ON_ONCE(!cpu_online(smp_processor_id())); | |
262 | ||
9f5a5621 | 263 | raw_spin_lock(&q->lock); |
15d0d3b3 | 264 | list_replace_init(&q->list, &list); |
9f5a5621 | 265 | raw_spin_unlock(&q->lock); |
3d442233 | 266 | |
15d0d3b3 NP |
267 | while (!list_empty(&list)) { |
268 | struct call_single_data *data; | |
3d442233 | 269 | |
0b13fda1 | 270 | data = list_entry(list.next, struct call_single_data, list); |
15d0d3b3 | 271 | list_del(&data->list); |
3d442233 | 272 | |
3d442233 | 273 | /* |
0b13fda1 IM |
274 | * 'data' can be invalid after this call if flags == 0 |
275 | * (when called through generic_exec_single()), | |
276 | * so save them away before making the call: | |
3d442233 | 277 | */ |
15d0d3b3 NP |
278 | data_flags = data->flags; |
279 | ||
280 | data->func(data->info); | |
281 | ||
8969a5ed | 282 | /* |
0b13fda1 | 283 | * Unlocked CSDs are valid through generic_exec_single(): |
8969a5ed PZ |
284 | */ |
285 | if (data_flags & CSD_FLAG_LOCK) | |
286 | csd_unlock(data); | |
3d442233 JA |
287 | } |
288 | } | |
289 | ||
e03bcb68 | 290 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); |
d7240b98 | 291 | |
3d442233 JA |
292 | /* |
293 | * smp_call_function_single - Run a function on a specific CPU | |
294 | * @func: The function to run. This must be fast and non-blocking. | |
295 | * @info: An arbitrary pointer to pass to the function. | |
3d442233 JA |
296 | * @wait: If true, wait until function has completed on other CPUs. |
297 | * | |
72f279b2 | 298 | * Returns 0 on success, else a negative status code. |
3d442233 | 299 | */ |
3a5f65df | 300 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, |
8691e5a8 | 301 | int wait) |
3d442233 | 302 | { |
8969a5ed PZ |
303 | struct call_single_data d = { |
304 | .flags = 0, | |
305 | }; | |
3d442233 | 306 | unsigned long flags; |
0b13fda1 | 307 | int this_cpu; |
f73be6de | 308 | int err = 0; |
3d442233 | 309 | |
0b13fda1 IM |
310 | /* |
311 | * prevent preemption and reschedule on another processor, | |
312 | * as well as CPU removal | |
313 | */ | |
314 | this_cpu = get_cpu(); | |
315 | ||
269c861b SS |
316 | /* |
317 | * Can deadlock when called with interrupts disabled. | |
318 | * We allow cpu's that are not yet online though, as no one else can | |
319 | * send smp call function interrupt to this cpu and as such deadlocks | |
320 | * can't happen. | |
321 | */ | |
322 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
323 | && !oops_in_progress); | |
3d442233 | 324 | |
0b13fda1 | 325 | if (cpu == this_cpu) { |
3d442233 JA |
326 | local_irq_save(flags); |
327 | func(info); | |
328 | local_irq_restore(flags); | |
0b13fda1 IM |
329 | } else { |
330 | if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { | |
331 | struct call_single_data *data = &d; | |
3d442233 | 332 | |
0b13fda1 IM |
333 | if (!wait) |
334 | data = &__get_cpu_var(csd_data); | |
6e275637 | 335 | |
0b13fda1 | 336 | csd_lock(data); |
3d442233 | 337 | |
0b13fda1 IM |
338 | data->func = func; |
339 | data->info = info; | |
340 | generic_exec_single(cpu, data, wait); | |
341 | } else { | |
342 | err = -ENXIO; /* CPU not online */ | |
343 | } | |
3d442233 JA |
344 | } |
345 | ||
346 | put_cpu(); | |
0b13fda1 | 347 | |
f73be6de | 348 | return err; |
3d442233 JA |
349 | } |
350 | EXPORT_SYMBOL(smp_call_function_single); | |
351 | ||
2ea6dec4 RR |
352 | /* |
353 | * smp_call_function_any - Run a function on any of the given cpus | |
354 | * @mask: The mask of cpus it can run on. | |
355 | * @func: The function to run. This must be fast and non-blocking. | |
356 | * @info: An arbitrary pointer to pass to the function. | |
357 | * @wait: If true, wait until function has completed. | |
358 | * | |
359 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
360 | * Note that @wait will be implicitly turned on in case of allocation failures, | |
361 | * since we fall back to on-stack allocation. | |
362 | * | |
363 | * Selection preference: | |
364 | * 1) current cpu if in @mask | |
365 | * 2) any cpu of current node if in @mask | |
366 | * 3) any other online cpu in @mask | |
367 | */ | |
368 | int smp_call_function_any(const struct cpumask *mask, | |
3a5f65df | 369 | smp_call_func_t func, void *info, int wait) |
2ea6dec4 RR |
370 | { |
371 | unsigned int cpu; | |
372 | const struct cpumask *nodemask; | |
373 | int ret; | |
374 | ||
375 | /* Try for same CPU (cheapest) */ | |
376 | cpu = get_cpu(); | |
377 | if (cpumask_test_cpu(cpu, mask)) | |
378 | goto call; | |
379 | ||
380 | /* Try for same node. */ | |
af2422c4 | 381 | nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2ea6dec4 RR |
382 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; |
383 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
384 | if (cpu_online(cpu)) | |
385 | goto call; | |
386 | } | |
387 | ||
388 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
389 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
390 | call: | |
391 | ret = smp_call_function_single(cpu, func, info, wait); | |
392 | put_cpu(); | |
393 | return ret; | |
394 | } | |
395 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
396 | ||
3d442233 | 397 | /** |
27c379f7 | 398 | * __smp_call_function_single(): Run a function on a specific CPU |
3d442233 JA |
399 | * @cpu: The CPU to run on. |
400 | * @data: Pre-allocated and setup data structure | |
27c379f7 | 401 | * @wait: If true, wait until function has completed on specified CPU. |
3d442233 | 402 | * |
0b13fda1 IM |
403 | * Like smp_call_function_single(), but allow caller to pass in a |
404 | * pre-allocated data structure. Useful for embedding @data inside | |
405 | * other structures, for instance. | |
3d442233 | 406 | */ |
6e275637 PZ |
407 | void __smp_call_function_single(int cpu, struct call_single_data *data, |
408 | int wait) | |
3d442233 | 409 | { |
27c379f7 HC |
410 | unsigned int this_cpu; |
411 | unsigned long flags; | |
6e275637 | 412 | |
27c379f7 | 413 | this_cpu = get_cpu(); |
269c861b SS |
414 | /* |
415 | * Can deadlock when called with interrupts disabled. | |
416 | * We allow cpu's that are not yet online though, as no one else can | |
417 | * send smp call function interrupt to this cpu and as such deadlocks | |
418 | * can't happen. | |
419 | */ | |
420 | WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled() | |
421 | && !oops_in_progress); | |
3d442233 | 422 | |
27c379f7 HC |
423 | if (cpu == this_cpu) { |
424 | local_irq_save(flags); | |
425 | data->func(data->info); | |
426 | local_irq_restore(flags); | |
427 | } else { | |
428 | csd_lock(data); | |
429 | generic_exec_single(cpu, data, wait); | |
430 | } | |
431 | put_cpu(); | |
3d442233 JA |
432 | } |
433 | ||
434 | /** | |
54b11e6d RR |
435 | * smp_call_function_many(): Run a function on a set of other CPUs. |
436 | * @mask: The set of cpus to run on (only runs on online subset). | |
3d442233 JA |
437 | * @func: The function to run. This must be fast and non-blocking. |
438 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
439 | * @wait: If true, wait (atomically) until function has completed |
440 | * on other CPUs. | |
3d442233 | 441 | * |
72f279b2 | 442 | * If @wait is true, then returns once @func has returned. |
3d442233 JA |
443 | * |
444 | * You must not call this function with disabled interrupts or from a | |
445 | * hardware interrupt handler or from a bottom half handler. Preemption | |
446 | * must be disabled when calling this function. | |
447 | */ | |
54b11e6d | 448 | void smp_call_function_many(const struct cpumask *mask, |
3a5f65df | 449 | smp_call_func_t func, void *info, bool wait) |
3d442233 | 450 | { |
54b11e6d | 451 | struct call_function_data *data; |
3d442233 | 452 | unsigned long flags; |
0b13fda1 | 453 | int cpu, next_cpu, this_cpu = smp_processor_id(); |
3d442233 | 454 | |
269c861b SS |
455 | /* |
456 | * Can deadlock when called with interrupts disabled. | |
457 | * We allow cpu's that are not yet online though, as no one else can | |
458 | * send smp call function interrupt to this cpu and as such deadlocks | |
459 | * can't happen. | |
460 | */ | |
461 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
bd924e8c | 462 | && !oops_in_progress && !early_boot_irqs_disabled); |
3d442233 | 463 | |
0b13fda1 | 464 | /* So, what's a CPU they want? Ignoring this one. */ |
54b11e6d | 465 | cpu = cpumask_first_and(mask, cpu_online_mask); |
0b13fda1 | 466 | if (cpu == this_cpu) |
54b11e6d | 467 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
0b13fda1 | 468 | |
54b11e6d RR |
469 | /* No online cpus? We're done. */ |
470 | if (cpu >= nr_cpu_ids) | |
471 | return; | |
472 | ||
473 | /* Do we have another CPU which isn't us? */ | |
474 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
0b13fda1 | 475 | if (next_cpu == this_cpu) |
54b11e6d RR |
476 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); |
477 | ||
478 | /* Fastpath: do that cpu by itself. */ | |
479 | if (next_cpu >= nr_cpu_ids) { | |
480 | smp_call_function_single(cpu, func, info, wait); | |
481 | return; | |
3d442233 JA |
482 | } |
483 | ||
8969a5ed PZ |
484 | data = &__get_cpu_var(cfd_data); |
485 | csd_lock(&data->csd); | |
6dc19899 | 486 | BUG_ON(atomic_read(&data->refs) || !cpumask_empty(data->cpumask)); |
3d442233 | 487 | |
3d442233 JA |
488 | data->csd.func = func; |
489 | data->csd.info = info; | |
8969a5ed | 490 | cpumask_and(data->cpumask, mask, cpu_online_mask); |
0b13fda1 | 491 | cpumask_clear_cpu(this_cpu, data->cpumask); |
6dc19899 AB |
492 | |
493 | /* | |
494 | * To ensure the interrupt handler gets an complete view | |
495 | * we order the cpumask and refs writes and order the read | |
496 | * of them in the interrupt handler. In addition we may | |
497 | * only clear our own cpu bit from the mask. | |
498 | */ | |
499 | smp_wmb(); | |
500 | ||
54fdade1 | 501 | atomic_set(&data->refs, cpumask_weight(data->cpumask)); |
3d442233 | 502 | |
9f5a5621 | 503 | raw_spin_lock_irqsave(&call_function.lock, flags); |
8969a5ed PZ |
504 | /* |
505 | * Place entry at the _HEAD_ of the list, so that any cpu still | |
0b13fda1 IM |
506 | * observing the entry in generic_smp_call_function_interrupt() |
507 | * will not miss any other list entries: | |
8969a5ed PZ |
508 | */ |
509 | list_add_rcu(&data->csd.list, &call_function.queue); | |
9f5a5621 | 510 | raw_spin_unlock_irqrestore(&call_function.lock, flags); |
3d442233 | 511 | |
561920a0 SS |
512 | /* |
513 | * Make the list addition visible before sending the ipi. | |
0b13fda1 IM |
514 | * (IPIs must obey or appear to obey normal Linux cache |
515 | * coherency rules -- see comment in generic_exec_single). | |
561920a0 SS |
516 | */ |
517 | smp_mb(); | |
518 | ||
3d442233 | 519 | /* Send a message to all CPUs in the map */ |
8969a5ed | 520 | arch_send_call_function_ipi_mask(data->cpumask); |
3d442233 | 521 | |
0b13fda1 | 522 | /* Optionally wait for the CPUs to complete */ |
54b11e6d | 523 | if (wait) |
6e275637 | 524 | csd_lock_wait(&data->csd); |
3d442233 | 525 | } |
54b11e6d | 526 | EXPORT_SYMBOL(smp_call_function_many); |
3d442233 JA |
527 | |
528 | /** | |
529 | * smp_call_function(): Run a function on all other CPUs. | |
530 | * @func: The function to run. This must be fast and non-blocking. | |
531 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
532 | * @wait: If true, wait (atomically) until function has completed |
533 | * on other CPUs. | |
3d442233 | 534 | * |
54b11e6d | 535 | * Returns 0. |
3d442233 JA |
536 | * |
537 | * If @wait is true, then returns once @func has returned; otherwise | |
72f279b2 | 538 | * it returns just before the target cpu calls @func. |
3d442233 JA |
539 | * |
540 | * You must not call this function with disabled interrupts or from a | |
541 | * hardware interrupt handler or from a bottom half handler. | |
542 | */ | |
3a5f65df | 543 | int smp_call_function(smp_call_func_t func, void *info, int wait) |
3d442233 | 544 | { |
3d442233 | 545 | preempt_disable(); |
54b11e6d | 546 | smp_call_function_many(cpu_online_mask, func, info, wait); |
3d442233 | 547 | preempt_enable(); |
0b13fda1 | 548 | |
54b11e6d | 549 | return 0; |
3d442233 JA |
550 | } |
551 | EXPORT_SYMBOL(smp_call_function); | |
552 | ||
553 | void ipi_call_lock(void) | |
554 | { | |
9f5a5621 | 555 | raw_spin_lock(&call_function.lock); |
3d442233 JA |
556 | } |
557 | ||
558 | void ipi_call_unlock(void) | |
559 | { | |
9f5a5621 | 560 | raw_spin_unlock(&call_function.lock); |
3d442233 JA |
561 | } |
562 | ||
563 | void ipi_call_lock_irq(void) | |
564 | { | |
9f5a5621 | 565 | raw_spin_lock_irq(&call_function.lock); |
3d442233 JA |
566 | } |
567 | ||
568 | void ipi_call_unlock_irq(void) | |
569 | { | |
9f5a5621 | 570 | raw_spin_unlock_irq(&call_function.lock); |
3d442233 | 571 | } |
351f8f8e AW |
572 | #endif /* USE_GENERIC_SMP_HELPERS */ |
573 | ||
574 | /* | |
bd924e8c TH |
575 | * Call a function on all processors. May be used during early boot while |
576 | * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead | |
577 | * of local_irq_disable/enable(). | |
351f8f8e AW |
578 | */ |
579 | int on_each_cpu(void (*func) (void *info), void *info, int wait) | |
580 | { | |
bd924e8c | 581 | unsigned long flags; |
351f8f8e AW |
582 | int ret = 0; |
583 | ||
584 | preempt_disable(); | |
585 | ret = smp_call_function(func, info, wait); | |
bd924e8c | 586 | local_irq_save(flags); |
351f8f8e | 587 | func(info); |
bd924e8c | 588 | local_irq_restore(flags); |
351f8f8e AW |
589 | preempt_enable(); |
590 | return ret; | |
591 | } | |
592 | EXPORT_SYMBOL(on_each_cpu); |