| 1 | /* |
| 2 | * linux/kernel/workqueue.c |
| 3 | * |
| 4 | * Generic mechanism for defining kernel helper threads for running |
| 5 | * arbitrary tasks in process context. |
| 6 | * |
| 7 | * Started by Ingo Molnar, Copyright (C) 2002 |
| 8 | * |
| 9 | * Derived from the taskqueue/keventd code by: |
| 10 | * |
| 11 | * David Woodhouse <dwmw2@infradead.org> |
| 12 | * Andrew Morton <andrewm@uow.edu.au> |
| 13 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> |
| 14 | * Theodore Ts'o <tytso@mit.edu> |
| 15 | * |
| 16 | * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/signal.h> |
| 24 | #include <linux/completion.h> |
| 25 | #include <linux/workqueue.h> |
| 26 | #include <linux/slab.h> |
| 27 | #include <linux/cpu.h> |
| 28 | #include <linux/notifier.h> |
| 29 | #include <linux/kthread.h> |
| 30 | #include <linux/hardirq.h> |
| 31 | #include <linux/mempolicy.h> |
| 32 | #include <linux/freezer.h> |
| 33 | #include <linux/kallsyms.h> |
| 34 | #include <linux/debug_locks.h> |
| 35 | |
| 36 | /* |
| 37 | * The per-CPU workqueue (if single thread, we always use the first |
| 38 | * possible cpu). |
| 39 | * |
| 40 | * The sequence counters are for flush_scheduled_work(). It wants to wait |
| 41 | * until all currently-scheduled works are completed, but it doesn't |
| 42 | * want to be livelocked by new, incoming ones. So it waits until |
| 43 | * remove_sequence is >= the insert_sequence which pertained when |
| 44 | * flush_scheduled_work() was called. |
| 45 | */ |
| 46 | struct cpu_workqueue_struct { |
| 47 | |
| 48 | spinlock_t lock; |
| 49 | |
| 50 | long remove_sequence; /* Least-recently added (next to run) */ |
| 51 | long insert_sequence; /* Next to add */ |
| 52 | |
| 53 | struct list_head worklist; |
| 54 | wait_queue_head_t more_work; |
| 55 | wait_queue_head_t work_done; |
| 56 | |
| 57 | struct workqueue_struct *wq; |
| 58 | struct task_struct *thread; |
| 59 | |
| 60 | int run_depth; /* Detect run_workqueue() recursion depth */ |
| 61 | |
| 62 | int freezeable; /* Freeze the thread during suspend */ |
| 63 | } ____cacheline_aligned; |
| 64 | |
| 65 | /* |
| 66 | * The externally visible workqueue abstraction is an array of |
| 67 | * per-CPU workqueues: |
| 68 | */ |
| 69 | struct workqueue_struct { |
| 70 | struct cpu_workqueue_struct *cpu_wq; |
| 71 | const char *name; |
| 72 | struct list_head list; /* Empty if single thread */ |
| 73 | }; |
| 74 | |
| 75 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove |
| 76 | threads to each one as cpus come/go. */ |
| 77 | static DEFINE_MUTEX(workqueue_mutex); |
| 78 | static LIST_HEAD(workqueues); |
| 79 | |
| 80 | static int singlethread_cpu; |
| 81 | |
| 82 | /* If it's single threaded, it isn't in the list of workqueues. */ |
| 83 | static inline int is_single_threaded(struct workqueue_struct *wq) |
| 84 | { |
| 85 | return list_empty(&wq->list); |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Set the workqueue on which a work item is to be run |
| 90 | * - Must *only* be called if the pending flag is set |
| 91 | */ |
| 92 | static inline void set_wq_data(struct work_struct *work, void *wq) |
| 93 | { |
| 94 | unsigned long new; |
| 95 | |
| 96 | BUG_ON(!work_pending(work)); |
| 97 | |
| 98 | new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING); |
| 99 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
| 100 | atomic_long_set(&work->data, new); |
| 101 | } |
| 102 | |
| 103 | static inline void *get_wq_data(struct work_struct *work) |
| 104 | { |
| 105 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
| 106 | } |
| 107 | |
| 108 | static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) |
| 109 | { |
| 110 | int ret = 0; |
| 111 | unsigned long flags; |
| 112 | |
| 113 | spin_lock_irqsave(&cwq->lock, flags); |
| 114 | /* |
| 115 | * We need to re-validate the work info after we've gotten |
| 116 | * the cpu_workqueue lock. We can run the work now iff: |
| 117 | * |
| 118 | * - the wq_data still matches the cpu_workqueue_struct |
| 119 | * - AND the work is still marked pending |
| 120 | * - AND the work is still on a list (which will be this |
| 121 | * workqueue_struct list) |
| 122 | * |
| 123 | * All these conditions are important, because we |
| 124 | * need to protect against the work being run right |
| 125 | * now on another CPU (all but the last one might be |
| 126 | * true if it's currently running and has not been |
| 127 | * released yet, for example). |
| 128 | */ |
| 129 | if (get_wq_data(work) == cwq |
| 130 | && work_pending(work) |
| 131 | && !list_empty(&work->entry)) { |
| 132 | work_func_t f = work->func; |
| 133 | list_del_init(&work->entry); |
| 134 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 135 | |
| 136 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) |
| 137 | work_release(work); |
| 138 | f(work); |
| 139 | |
| 140 | spin_lock_irqsave(&cwq->lock, flags); |
| 141 | cwq->remove_sequence++; |
| 142 | wake_up(&cwq->work_done); |
| 143 | ret = 1; |
| 144 | } |
| 145 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 146 | return ret; |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * run_scheduled_work - run scheduled work synchronously |
| 151 | * @work: work to run |
| 152 | * |
| 153 | * This checks if the work was pending, and runs it |
| 154 | * synchronously if so. It returns a boolean to indicate |
| 155 | * whether it had any scheduled work to run or not. |
| 156 | * |
| 157 | * NOTE! This _only_ works for normal work_structs. You |
| 158 | * CANNOT use this for delayed work, because the wq data |
| 159 | * for delayed work will not point properly to the per- |
| 160 | * CPU workqueue struct, but will change! |
| 161 | */ |
| 162 | int fastcall run_scheduled_work(struct work_struct *work) |
| 163 | { |
| 164 | for (;;) { |
| 165 | struct cpu_workqueue_struct *cwq; |
| 166 | |
| 167 | if (!work_pending(work)) |
| 168 | return 0; |
| 169 | if (list_empty(&work->entry)) |
| 170 | return 0; |
| 171 | /* NOTE! This depends intimately on __queue_work! */ |
| 172 | cwq = get_wq_data(work); |
| 173 | if (!cwq) |
| 174 | return 0; |
| 175 | if (__run_work(cwq, work)) |
| 176 | return 1; |
| 177 | } |
| 178 | } |
| 179 | EXPORT_SYMBOL(run_scheduled_work); |
| 180 | |
| 181 | /* Preempt must be disabled. */ |
| 182 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
| 183 | struct work_struct *work) |
| 184 | { |
| 185 | unsigned long flags; |
| 186 | |
| 187 | spin_lock_irqsave(&cwq->lock, flags); |
| 188 | set_wq_data(work, cwq); |
| 189 | list_add_tail(&work->entry, &cwq->worklist); |
| 190 | cwq->insert_sequence++; |
| 191 | wake_up(&cwq->more_work); |
| 192 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * queue_work - queue work on a workqueue |
| 197 | * @wq: workqueue to use |
| 198 | * @work: work to queue |
| 199 | * |
| 200 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
| 201 | * |
| 202 | * We queue the work to the CPU it was submitted, but there is no |
| 203 | * guarantee that it will be processed by that CPU. |
| 204 | */ |
| 205 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) |
| 206 | { |
| 207 | int ret = 0, cpu = get_cpu(); |
| 208 | |
| 209 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
| 210 | if (unlikely(is_single_threaded(wq))) |
| 211 | cpu = singlethread_cpu; |
| 212 | BUG_ON(!list_empty(&work->entry)); |
| 213 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
| 214 | ret = 1; |
| 215 | } |
| 216 | put_cpu(); |
| 217 | return ret; |
| 218 | } |
| 219 | EXPORT_SYMBOL_GPL(queue_work); |
| 220 | |
| 221 | static void delayed_work_timer_fn(unsigned long __data) |
| 222 | { |
| 223 | struct delayed_work *dwork = (struct delayed_work *)__data; |
| 224 | struct workqueue_struct *wq = get_wq_data(&dwork->work); |
| 225 | int cpu = smp_processor_id(); |
| 226 | |
| 227 | if (unlikely(is_single_threaded(wq))) |
| 228 | cpu = singlethread_cpu; |
| 229 | |
| 230 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); |
| 231 | } |
| 232 | |
| 233 | /** |
| 234 | * queue_delayed_work - queue work on a workqueue after delay |
| 235 | * @wq: workqueue to use |
| 236 | * @work: delayable work to queue |
| 237 | * @delay: number of jiffies to wait before queueing |
| 238 | * |
| 239 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
| 240 | */ |
| 241 | int fastcall queue_delayed_work(struct workqueue_struct *wq, |
| 242 | struct delayed_work *dwork, unsigned long delay) |
| 243 | { |
| 244 | int ret = 0; |
| 245 | struct timer_list *timer = &dwork->timer; |
| 246 | struct work_struct *work = &dwork->work; |
| 247 | |
| 248 | if (delay == 0) |
| 249 | return queue_work(wq, work); |
| 250 | |
| 251 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
| 252 | BUG_ON(timer_pending(timer)); |
| 253 | BUG_ON(!list_empty(&work->entry)); |
| 254 | |
| 255 | /* This stores wq for the moment, for the timer_fn */ |
| 256 | set_wq_data(work, wq); |
| 257 | timer->expires = jiffies + delay; |
| 258 | timer->data = (unsigned long)dwork; |
| 259 | timer->function = delayed_work_timer_fn; |
| 260 | add_timer(timer); |
| 261 | ret = 1; |
| 262 | } |
| 263 | return ret; |
| 264 | } |
| 265 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
| 266 | |
| 267 | /** |
| 268 | * queue_delayed_work_on - queue work on specific CPU after delay |
| 269 | * @cpu: CPU number to execute work on |
| 270 | * @wq: workqueue to use |
| 271 | * @work: work to queue |
| 272 | * @delay: number of jiffies to wait before queueing |
| 273 | * |
| 274 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
| 275 | */ |
| 276 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
| 277 | struct delayed_work *dwork, unsigned long delay) |
| 278 | { |
| 279 | int ret = 0; |
| 280 | struct timer_list *timer = &dwork->timer; |
| 281 | struct work_struct *work = &dwork->work; |
| 282 | |
| 283 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
| 284 | BUG_ON(timer_pending(timer)); |
| 285 | BUG_ON(!list_empty(&work->entry)); |
| 286 | |
| 287 | /* This stores wq for the moment, for the timer_fn */ |
| 288 | set_wq_data(work, wq); |
| 289 | timer->expires = jiffies + delay; |
| 290 | timer->data = (unsigned long)dwork; |
| 291 | timer->function = delayed_work_timer_fn; |
| 292 | add_timer_on(timer, cpu); |
| 293 | ret = 1; |
| 294 | } |
| 295 | return ret; |
| 296 | } |
| 297 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
| 298 | |
| 299 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
| 300 | { |
| 301 | unsigned long flags; |
| 302 | |
| 303 | /* |
| 304 | * Keep taking off work from the queue until |
| 305 | * done. |
| 306 | */ |
| 307 | spin_lock_irqsave(&cwq->lock, flags); |
| 308 | cwq->run_depth++; |
| 309 | if (cwq->run_depth > 3) { |
| 310 | /* morton gets to eat his hat */ |
| 311 | printk("%s: recursion depth exceeded: %d\n", |
| 312 | __FUNCTION__, cwq->run_depth); |
| 313 | dump_stack(); |
| 314 | } |
| 315 | while (!list_empty(&cwq->worklist)) { |
| 316 | struct work_struct *work = list_entry(cwq->worklist.next, |
| 317 | struct work_struct, entry); |
| 318 | work_func_t f = work->func; |
| 319 | |
| 320 | list_del_init(cwq->worklist.next); |
| 321 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 322 | |
| 323 | BUG_ON(get_wq_data(work) != cwq); |
| 324 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) |
| 325 | work_release(work); |
| 326 | f(work); |
| 327 | |
| 328 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
| 329 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " |
| 330 | "%s/0x%08x/%d\n", |
| 331 | current->comm, preempt_count(), |
| 332 | current->pid); |
| 333 | printk(KERN_ERR " last function: "); |
| 334 | print_symbol("%s\n", (unsigned long)f); |
| 335 | debug_show_held_locks(current); |
| 336 | dump_stack(); |
| 337 | } |
| 338 | |
| 339 | spin_lock_irqsave(&cwq->lock, flags); |
| 340 | cwq->remove_sequence++; |
| 341 | wake_up(&cwq->work_done); |
| 342 | } |
| 343 | cwq->run_depth--; |
| 344 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 345 | } |
| 346 | |
| 347 | static int worker_thread(void *__cwq) |
| 348 | { |
| 349 | struct cpu_workqueue_struct *cwq = __cwq; |
| 350 | DECLARE_WAITQUEUE(wait, current); |
| 351 | struct k_sigaction sa; |
| 352 | sigset_t blocked; |
| 353 | |
| 354 | if (!cwq->freezeable) |
| 355 | current->flags |= PF_NOFREEZE; |
| 356 | |
| 357 | set_user_nice(current, -5); |
| 358 | |
| 359 | /* Block and flush all signals */ |
| 360 | sigfillset(&blocked); |
| 361 | sigprocmask(SIG_BLOCK, &blocked, NULL); |
| 362 | flush_signals(current); |
| 363 | |
| 364 | /* |
| 365 | * We inherited MPOL_INTERLEAVE from the booting kernel. |
| 366 | * Set MPOL_DEFAULT to insure node local allocations. |
| 367 | */ |
| 368 | numa_default_policy(); |
| 369 | |
| 370 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ |
| 371 | sa.sa.sa_handler = SIG_IGN; |
| 372 | sa.sa.sa_flags = 0; |
| 373 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); |
| 374 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); |
| 375 | |
| 376 | set_current_state(TASK_INTERRUPTIBLE); |
| 377 | while (!kthread_should_stop()) { |
| 378 | if (cwq->freezeable) |
| 379 | try_to_freeze(); |
| 380 | |
| 381 | add_wait_queue(&cwq->more_work, &wait); |
| 382 | if (list_empty(&cwq->worklist)) |
| 383 | schedule(); |
| 384 | else |
| 385 | __set_current_state(TASK_RUNNING); |
| 386 | remove_wait_queue(&cwq->more_work, &wait); |
| 387 | |
| 388 | if (!list_empty(&cwq->worklist)) |
| 389 | run_workqueue(cwq); |
| 390 | set_current_state(TASK_INTERRUPTIBLE); |
| 391 | } |
| 392 | __set_current_state(TASK_RUNNING); |
| 393 | return 0; |
| 394 | } |
| 395 | |
| 396 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
| 397 | { |
| 398 | if (cwq->thread == current) { |
| 399 | /* |
| 400 | * Probably keventd trying to flush its own queue. So simply run |
| 401 | * it by hand rather than deadlocking. |
| 402 | */ |
| 403 | run_workqueue(cwq); |
| 404 | } else { |
| 405 | DEFINE_WAIT(wait); |
| 406 | long sequence_needed; |
| 407 | |
| 408 | spin_lock_irq(&cwq->lock); |
| 409 | sequence_needed = cwq->insert_sequence; |
| 410 | |
| 411 | while (sequence_needed - cwq->remove_sequence > 0) { |
| 412 | prepare_to_wait(&cwq->work_done, &wait, |
| 413 | TASK_UNINTERRUPTIBLE); |
| 414 | spin_unlock_irq(&cwq->lock); |
| 415 | schedule(); |
| 416 | spin_lock_irq(&cwq->lock); |
| 417 | } |
| 418 | finish_wait(&cwq->work_done, &wait); |
| 419 | spin_unlock_irq(&cwq->lock); |
| 420 | } |
| 421 | } |
| 422 | |
| 423 | /** |
| 424 | * flush_workqueue - ensure that any scheduled work has run to completion. |
| 425 | * @wq: workqueue to flush |
| 426 | * |
| 427 | * Forces execution of the workqueue and blocks until its completion. |
| 428 | * This is typically used in driver shutdown handlers. |
| 429 | * |
| 430 | * This function will sample each workqueue's current insert_sequence number and |
| 431 | * will sleep until the head sequence is greater than or equal to that. This |
| 432 | * means that we sleep until all works which were queued on entry have been |
| 433 | * handled, but we are not livelocked by new incoming ones. |
| 434 | * |
| 435 | * This function used to run the workqueues itself. Now we just wait for the |
| 436 | * helper threads to do it. |
| 437 | */ |
| 438 | void fastcall flush_workqueue(struct workqueue_struct *wq) |
| 439 | { |
| 440 | might_sleep(); |
| 441 | |
| 442 | if (is_single_threaded(wq)) { |
| 443 | /* Always use first cpu's area. */ |
| 444 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); |
| 445 | } else { |
| 446 | int cpu; |
| 447 | |
| 448 | mutex_lock(&workqueue_mutex); |
| 449 | for_each_online_cpu(cpu) |
| 450 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
| 451 | mutex_unlock(&workqueue_mutex); |
| 452 | } |
| 453 | } |
| 454 | EXPORT_SYMBOL_GPL(flush_workqueue); |
| 455 | |
| 456 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, |
| 457 | int cpu, int freezeable) |
| 458 | { |
| 459 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| 460 | struct task_struct *p; |
| 461 | |
| 462 | spin_lock_init(&cwq->lock); |
| 463 | cwq->wq = wq; |
| 464 | cwq->thread = NULL; |
| 465 | cwq->insert_sequence = 0; |
| 466 | cwq->remove_sequence = 0; |
| 467 | cwq->freezeable = freezeable; |
| 468 | INIT_LIST_HEAD(&cwq->worklist); |
| 469 | init_waitqueue_head(&cwq->more_work); |
| 470 | init_waitqueue_head(&cwq->work_done); |
| 471 | |
| 472 | if (is_single_threaded(wq)) |
| 473 | p = kthread_create(worker_thread, cwq, "%s", wq->name); |
| 474 | else |
| 475 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); |
| 476 | if (IS_ERR(p)) |
| 477 | return NULL; |
| 478 | cwq->thread = p; |
| 479 | return p; |
| 480 | } |
| 481 | |
| 482 | struct workqueue_struct *__create_workqueue(const char *name, |
| 483 | int singlethread, int freezeable) |
| 484 | { |
| 485 | int cpu, destroy = 0; |
| 486 | struct workqueue_struct *wq; |
| 487 | struct task_struct *p; |
| 488 | |
| 489 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
| 490 | if (!wq) |
| 491 | return NULL; |
| 492 | |
| 493 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
| 494 | if (!wq->cpu_wq) { |
| 495 | kfree(wq); |
| 496 | return NULL; |
| 497 | } |
| 498 | |
| 499 | wq->name = name; |
| 500 | mutex_lock(&workqueue_mutex); |
| 501 | if (singlethread) { |
| 502 | INIT_LIST_HEAD(&wq->list); |
| 503 | p = create_workqueue_thread(wq, singlethread_cpu, freezeable); |
| 504 | if (!p) |
| 505 | destroy = 1; |
| 506 | else |
| 507 | wake_up_process(p); |
| 508 | } else { |
| 509 | list_add(&wq->list, &workqueues); |
| 510 | for_each_online_cpu(cpu) { |
| 511 | p = create_workqueue_thread(wq, cpu, freezeable); |
| 512 | if (p) { |
| 513 | kthread_bind(p, cpu); |
| 514 | wake_up_process(p); |
| 515 | } else |
| 516 | destroy = 1; |
| 517 | } |
| 518 | } |
| 519 | mutex_unlock(&workqueue_mutex); |
| 520 | |
| 521 | /* |
| 522 | * Was there any error during startup? If yes then clean up: |
| 523 | */ |
| 524 | if (destroy) { |
| 525 | destroy_workqueue(wq); |
| 526 | wq = NULL; |
| 527 | } |
| 528 | return wq; |
| 529 | } |
| 530 | EXPORT_SYMBOL_GPL(__create_workqueue); |
| 531 | |
| 532 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) |
| 533 | { |
| 534 | struct cpu_workqueue_struct *cwq; |
| 535 | unsigned long flags; |
| 536 | struct task_struct *p; |
| 537 | |
| 538 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| 539 | spin_lock_irqsave(&cwq->lock, flags); |
| 540 | p = cwq->thread; |
| 541 | cwq->thread = NULL; |
| 542 | spin_unlock_irqrestore(&cwq->lock, flags); |
| 543 | if (p) |
| 544 | kthread_stop(p); |
| 545 | } |
| 546 | |
| 547 | /** |
| 548 | * destroy_workqueue - safely terminate a workqueue |
| 549 | * @wq: target workqueue |
| 550 | * |
| 551 | * Safely destroy a workqueue. All work currently pending will be done first. |
| 552 | */ |
| 553 | void destroy_workqueue(struct workqueue_struct *wq) |
| 554 | { |
| 555 | int cpu; |
| 556 | |
| 557 | flush_workqueue(wq); |
| 558 | |
| 559 | /* We don't need the distraction of CPUs appearing and vanishing. */ |
| 560 | mutex_lock(&workqueue_mutex); |
| 561 | if (is_single_threaded(wq)) |
| 562 | cleanup_workqueue_thread(wq, singlethread_cpu); |
| 563 | else { |
| 564 | for_each_online_cpu(cpu) |
| 565 | cleanup_workqueue_thread(wq, cpu); |
| 566 | list_del(&wq->list); |
| 567 | } |
| 568 | mutex_unlock(&workqueue_mutex); |
| 569 | free_percpu(wq->cpu_wq); |
| 570 | kfree(wq); |
| 571 | } |
| 572 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
| 573 | |
| 574 | static struct workqueue_struct *keventd_wq; |
| 575 | |
| 576 | /** |
| 577 | * schedule_work - put work task in global workqueue |
| 578 | * @work: job to be done |
| 579 | * |
| 580 | * This puts a job in the kernel-global workqueue. |
| 581 | */ |
| 582 | int fastcall schedule_work(struct work_struct *work) |
| 583 | { |
| 584 | return queue_work(keventd_wq, work); |
| 585 | } |
| 586 | EXPORT_SYMBOL(schedule_work); |
| 587 | |
| 588 | /** |
| 589 | * schedule_delayed_work - put work task in global workqueue after delay |
| 590 | * @dwork: job to be done |
| 591 | * @delay: number of jiffies to wait or 0 for immediate execution |
| 592 | * |
| 593 | * After waiting for a given time this puts a job in the kernel-global |
| 594 | * workqueue. |
| 595 | */ |
| 596 | int fastcall schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) |
| 597 | { |
| 598 | return queue_delayed_work(keventd_wq, dwork, delay); |
| 599 | } |
| 600 | EXPORT_SYMBOL(schedule_delayed_work); |
| 601 | |
| 602 | /** |
| 603 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay |
| 604 | * @cpu: cpu to use |
| 605 | * @dwork: job to be done |
| 606 | * @delay: number of jiffies to wait |
| 607 | * |
| 608 | * After waiting for a given time this puts a job in the kernel-global |
| 609 | * workqueue on the specified CPU. |
| 610 | */ |
| 611 | int schedule_delayed_work_on(int cpu, |
| 612 | struct delayed_work *dwork, unsigned long delay) |
| 613 | { |
| 614 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
| 615 | } |
| 616 | EXPORT_SYMBOL(schedule_delayed_work_on); |
| 617 | |
| 618 | /** |
| 619 | * schedule_on_each_cpu - call a function on each online CPU from keventd |
| 620 | * @func: the function to call |
| 621 | * |
| 622 | * Returns zero on success. |
| 623 | * Returns -ve errno on failure. |
| 624 | * |
| 625 | * Appears to be racy against CPU hotplug. |
| 626 | * |
| 627 | * schedule_on_each_cpu() is very slow. |
| 628 | */ |
| 629 | int schedule_on_each_cpu(work_func_t func) |
| 630 | { |
| 631 | int cpu; |
| 632 | struct work_struct *works; |
| 633 | |
| 634 | works = alloc_percpu(struct work_struct); |
| 635 | if (!works) |
| 636 | return -ENOMEM; |
| 637 | |
| 638 | mutex_lock(&workqueue_mutex); |
| 639 | for_each_online_cpu(cpu) { |
| 640 | INIT_WORK(per_cpu_ptr(works, cpu), func); |
| 641 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), |
| 642 | per_cpu_ptr(works, cpu)); |
| 643 | } |
| 644 | mutex_unlock(&workqueue_mutex); |
| 645 | flush_workqueue(keventd_wq); |
| 646 | free_percpu(works); |
| 647 | return 0; |
| 648 | } |
| 649 | |
| 650 | void flush_scheduled_work(void) |
| 651 | { |
| 652 | flush_workqueue(keventd_wq); |
| 653 | } |
| 654 | EXPORT_SYMBOL(flush_scheduled_work); |
| 655 | |
| 656 | /** |
| 657 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed |
| 658 | * work whose handler rearms the delayed work. |
| 659 | * @wq: the controlling workqueue structure |
| 660 | * @dwork: the delayed work struct |
| 661 | */ |
| 662 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
| 663 | struct delayed_work *dwork) |
| 664 | { |
| 665 | while (!cancel_delayed_work(dwork)) |
| 666 | flush_workqueue(wq); |
| 667 | } |
| 668 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
| 669 | |
| 670 | /** |
| 671 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd |
| 672 | * work whose handler rearms the delayed work. |
| 673 | * @dwork: the delayed work struct |
| 674 | */ |
| 675 | void cancel_rearming_delayed_work(struct delayed_work *dwork) |
| 676 | { |
| 677 | cancel_rearming_delayed_workqueue(keventd_wq, dwork); |
| 678 | } |
| 679 | EXPORT_SYMBOL(cancel_rearming_delayed_work); |
| 680 | |
| 681 | /** |
| 682 | * execute_in_process_context - reliably execute the routine with user context |
| 683 | * @fn: the function to execute |
| 684 | * @ew: guaranteed storage for the execute work structure (must |
| 685 | * be available when the work executes) |
| 686 | * |
| 687 | * Executes the function immediately if process context is available, |
| 688 | * otherwise schedules the function for delayed execution. |
| 689 | * |
| 690 | * Returns: 0 - function was executed |
| 691 | * 1 - function was scheduled for execution |
| 692 | */ |
| 693 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
| 694 | { |
| 695 | if (!in_interrupt()) { |
| 696 | fn(&ew->work); |
| 697 | return 0; |
| 698 | } |
| 699 | |
| 700 | INIT_WORK(&ew->work, fn); |
| 701 | schedule_work(&ew->work); |
| 702 | |
| 703 | return 1; |
| 704 | } |
| 705 | EXPORT_SYMBOL_GPL(execute_in_process_context); |
| 706 | |
| 707 | int keventd_up(void) |
| 708 | { |
| 709 | return keventd_wq != NULL; |
| 710 | } |
| 711 | |
| 712 | int current_is_keventd(void) |
| 713 | { |
| 714 | struct cpu_workqueue_struct *cwq; |
| 715 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
| 716 | int ret = 0; |
| 717 | |
| 718 | BUG_ON(!keventd_wq); |
| 719 | |
| 720 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
| 721 | if (current == cwq->thread) |
| 722 | ret = 1; |
| 723 | |
| 724 | return ret; |
| 725 | |
| 726 | } |
| 727 | |
| 728 | /* Take the work from this (downed) CPU. */ |
| 729 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) |
| 730 | { |
| 731 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| 732 | struct list_head list; |
| 733 | struct work_struct *work; |
| 734 | |
| 735 | spin_lock_irq(&cwq->lock); |
| 736 | list_replace_init(&cwq->worklist, &list); |
| 737 | |
| 738 | while (!list_empty(&list)) { |
| 739 | printk("Taking work for %s\n", wq->name); |
| 740 | work = list_entry(list.next,struct work_struct,entry); |
| 741 | list_del(&work->entry); |
| 742 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); |
| 743 | } |
| 744 | spin_unlock_irq(&cwq->lock); |
| 745 | } |
| 746 | |
| 747 | /* We're holding the cpucontrol mutex here */ |
| 748 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
| 749 | unsigned long action, |
| 750 | void *hcpu) |
| 751 | { |
| 752 | unsigned int hotcpu = (unsigned long)hcpu; |
| 753 | struct workqueue_struct *wq; |
| 754 | |
| 755 | switch (action) { |
| 756 | case CPU_UP_PREPARE: |
| 757 | mutex_lock(&workqueue_mutex); |
| 758 | /* Create a new workqueue thread for it. */ |
| 759 | list_for_each_entry(wq, &workqueues, list) { |
| 760 | if (!create_workqueue_thread(wq, hotcpu, 0)) { |
| 761 | printk("workqueue for %i failed\n", hotcpu); |
| 762 | return NOTIFY_BAD; |
| 763 | } |
| 764 | } |
| 765 | break; |
| 766 | |
| 767 | case CPU_ONLINE: |
| 768 | /* Kick off worker threads. */ |
| 769 | list_for_each_entry(wq, &workqueues, list) { |
| 770 | struct cpu_workqueue_struct *cwq; |
| 771 | |
| 772 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); |
| 773 | kthread_bind(cwq->thread, hotcpu); |
| 774 | wake_up_process(cwq->thread); |
| 775 | } |
| 776 | mutex_unlock(&workqueue_mutex); |
| 777 | break; |
| 778 | |
| 779 | case CPU_UP_CANCELED: |
| 780 | list_for_each_entry(wq, &workqueues, list) { |
| 781 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) |
| 782 | continue; |
| 783 | /* Unbind so it can run. */ |
| 784 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, |
| 785 | any_online_cpu(cpu_online_map)); |
| 786 | cleanup_workqueue_thread(wq, hotcpu); |
| 787 | } |
| 788 | mutex_unlock(&workqueue_mutex); |
| 789 | break; |
| 790 | |
| 791 | case CPU_DOWN_PREPARE: |
| 792 | mutex_lock(&workqueue_mutex); |
| 793 | break; |
| 794 | |
| 795 | case CPU_DOWN_FAILED: |
| 796 | mutex_unlock(&workqueue_mutex); |
| 797 | break; |
| 798 | |
| 799 | case CPU_DEAD: |
| 800 | list_for_each_entry(wq, &workqueues, list) |
| 801 | cleanup_workqueue_thread(wq, hotcpu); |
| 802 | list_for_each_entry(wq, &workqueues, list) |
| 803 | take_over_work(wq, hotcpu); |
| 804 | mutex_unlock(&workqueue_mutex); |
| 805 | break; |
| 806 | } |
| 807 | |
| 808 | return NOTIFY_OK; |
| 809 | } |
| 810 | |
| 811 | void init_workqueues(void) |
| 812 | { |
| 813 | singlethread_cpu = first_cpu(cpu_possible_map); |
| 814 | hotcpu_notifier(workqueue_cpu_callback, 0); |
| 815 | keventd_wq = create_workqueue("events"); |
| 816 | BUG_ON(!keventd_wq); |
| 817 | } |
| 818 | |