blob: 8db0b597509e5bd2d8e630911137ea50aae42030 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Christoph Lameter89ada672005-10-30 15:01:59 -080015 *
16 * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>.
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 */
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>
James Bottomley1fa44ec2006-02-23 12:43:43 -060030#include <linux/hardirq.h>
Christoph Lameter469340232006-10-11 01:21:26 -070031#include <linux/mempolicy.h>
Rafael J. Wysocki341a5952006-12-06 20:34:49 -080032#include <linux/freezer.h>
Peter Zijlstrad5abe662006-12-06 20:37:26 -080033#include <linux/kallsyms.h>
34#include <linux/debug_locks.h>
Johannes Berg4e6045f2007-10-18 23:39:55 -070035#include <linux/lockdep.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
37/*
Nathan Lynchf756d5e2006-01-08 01:05:12 -080038 * The per-CPU workqueue (if single thread, we always use the first
39 * possible cpu).
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 */
41struct cpu_workqueue_struct {
42
43 spinlock_t lock;
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 struct list_head worklist;
46 wait_queue_head_t more_work;
Oleg Nesterov3af244332007-05-09 02:34:09 -070047 struct work_struct *current_work;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
49 struct workqueue_struct *wq;
Ingo Molnar36c8b582006-07-03 00:25:41 -070050 struct task_struct *thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52 int run_depth; /* Detect run_workqueue() recursion depth */
53} ____cacheline_aligned;
54
55/*
56 * The externally visible workqueue abstraction is an array of
57 * per-CPU workqueues:
58 */
59struct workqueue_struct {
Christoph Lameter89ada672005-10-30 15:01:59 -080060 struct cpu_workqueue_struct *cpu_wq;
Oleg Nesterovcce1a162007-05-09 02:34:13 -070061 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 const char *name;
Oleg Nesterovcce1a162007-05-09 02:34:13 -070063 int singlethread;
Oleg Nesterov319c2a92007-05-09 02:34:06 -070064 int freezeable; /* Freeze threads during suspend */
Johannes Berg4e6045f2007-10-18 23:39:55 -070065#ifdef CONFIG_LOCKDEP
66 struct lockdep_map lockdep_map;
67#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070068};
69
70/* All the per-cpu workqueues on the system, for hotplug cpu to add/remove
71 threads to each one as cpus come/go. */
Andrew Morton9b41ea72006-08-13 23:24:26 -070072static DEFINE_MUTEX(workqueue_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073static LIST_HEAD(workqueues);
74
Oleg Nesterov3af244332007-05-09 02:34:09 -070075static int singlethread_cpu __read_mostly;
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -070076static cpumask_t cpu_singlethread_map __read_mostly;
Oleg Nesterov14441962007-05-23 13:57:57 -070077/*
78 * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
79 * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
80 * which comes in between can't use for_each_online_cpu(). We could
81 * use cpu_possible_map, the cpumask below is more a documentation
82 * than optimization.
83 */
Oleg Nesterov3af244332007-05-09 02:34:09 -070084static cpumask_t cpu_populated_map __read_mostly;
Nathan Lynchf756d5e2006-01-08 01:05:12 -080085
Linus Torvalds1da177e2005-04-16 15:20:36 -070086/* If it's single threaded, it isn't in the list of workqueues. */
87static inline int is_single_threaded(struct workqueue_struct *wq)
88{
Oleg Nesterovcce1a162007-05-09 02:34:13 -070089 return wq->singlethread;
Linus Torvalds1da177e2005-04-16 15:20:36 -070090}
91
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -070092static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
93{
94 return is_single_threaded(wq)
95 ? &cpu_singlethread_map : &cpu_populated_map;
96}
97
Oleg Nesterova848e3b2007-05-09 02:34:17 -070098static
99struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
100{
101 if (unlikely(is_single_threaded(wq)))
102 cpu = singlethread_cpu;
103 return per_cpu_ptr(wq->cpu_wq, cpu);
104}
105
David Howells4594bf12006-12-07 11:33:26 +0000106/*
107 * Set the workqueue on which a work item is to be run
108 * - Must *only* be called if the pending flag is set
109 */
Oleg Nesteroved7c0fe2007-05-09 02:34:16 -0700110static inline void set_wq_data(struct work_struct *work,
111 struct cpu_workqueue_struct *cwq)
David Howells365970a2006-11-22 14:54:49 +0000112{
David Howells4594bf12006-12-07 11:33:26 +0000113 unsigned long new;
David Howells365970a2006-11-22 14:54:49 +0000114
David Howells4594bf12006-12-07 11:33:26 +0000115 BUG_ON(!work_pending(work));
116
Oleg Nesteroved7c0fe2007-05-09 02:34:16 -0700117 new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800118 new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
119 atomic_long_set(&work->data, new);
David Howells365970a2006-11-22 14:54:49 +0000120}
121
Oleg Nesteroved7c0fe2007-05-09 02:34:16 -0700122static inline
123struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
David Howells365970a2006-11-22 14:54:49 +0000124{
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800125 return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
David Howells365970a2006-11-22 14:54:49 +0000126}
127
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700128static void insert_work(struct cpu_workqueue_struct *cwq,
129 struct work_struct *work, int tail)
130{
131 set_wq_data(work, cwq);
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700132 /*
133 * Ensure that we get the right work->data if we see the
134 * result of list_add() below, see try_to_grab_pending().
135 */
136 smp_wmb();
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700137 if (tail)
138 list_add_tail(&work->entry, &cwq->worklist);
139 else
140 list_add(&work->entry, &cwq->worklist);
141 wake_up(&cwq->more_work);
142}
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144/* Preempt must be disabled. */
145static void __queue_work(struct cpu_workqueue_struct *cwq,
146 struct work_struct *work)
147{
148 unsigned long flags;
149
150 spin_lock_irqsave(&cwq->lock, flags);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700151 insert_work(cwq, work, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 spin_unlock_irqrestore(&cwq->lock, flags);
153}
154
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700155/**
156 * queue_work - queue work on a workqueue
157 * @wq: workqueue to use
158 * @work: work to queue
159 *
Alan Stern057647f2006-10-28 10:38:58 -0700160 * Returns 0 if @work was already on a queue, non-zero otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 *
162 * We queue the work to the CPU it was submitted, but there is no
163 * guarantee that it will be processed by that CPU.
164 */
165int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
166{
Oleg Nesterova848e3b2007-05-09 02:34:17 -0700167 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800169 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 BUG_ON(!list_empty(&work->entry));
Oleg Nesterova848e3b2007-05-09 02:34:17 -0700171 __queue_work(wq_per_cpu(wq, get_cpu()), work);
172 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 ret = 1;
174 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 return ret;
176}
Dave Jonesae90dd52006-06-30 01:40:45 -0400177EXPORT_SYMBOL_GPL(queue_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800179void delayed_work_timer_fn(unsigned long __data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180{
David Howells52bad642006-11-22 14:54:01 +0000181 struct delayed_work *dwork = (struct delayed_work *)__data;
Oleg Nesteroved7c0fe2007-05-09 02:34:16 -0700182 struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
183 struct workqueue_struct *wq = cwq->wq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
Oleg Nesterova848e3b2007-05-09 02:34:17 -0700185 __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}
187
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700188/**
189 * queue_delayed_work - queue work on a workqueue after delay
190 * @wq: workqueue to use
Randy Dunlapaf9997e2006-12-22 01:06:52 -0800191 * @dwork: delayable work to queue
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700192 * @delay: number of jiffies to wait before queueing
193 *
Alan Stern057647f2006-10-28 10:38:58 -0700194 * Returns 0 if @work was already on a queue, non-zero otherwise.
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700195 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196int fastcall queue_delayed_work(struct workqueue_struct *wq,
David Howells52bad642006-11-22 14:54:01 +0000197 struct delayed_work *dwork, unsigned long delay)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198{
Oleg Nesterov63bc0362007-05-09 02:34:16 -0700199 timer_stats_timer_set_start_info(&dwork->timer);
David Howells52bad642006-11-22 14:54:01 +0000200 if (delay == 0)
Oleg Nesterov63bc0362007-05-09 02:34:16 -0700201 return queue_work(wq, &dwork->work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
Oleg Nesterov63bc0362007-05-09 02:34:16 -0700203 return queue_delayed_work_on(-1, wq, dwork, delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204}
Dave Jonesae90dd52006-06-30 01:40:45 -0400205EXPORT_SYMBOL_GPL(queue_delayed_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700207/**
208 * queue_delayed_work_on - queue work on specific CPU after delay
209 * @cpu: CPU number to execute work on
210 * @wq: workqueue to use
Randy Dunlapaf9997e2006-12-22 01:06:52 -0800211 * @dwork: work to queue
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700212 * @delay: number of jiffies to wait before queueing
213 *
Alan Stern057647f2006-10-28 10:38:58 -0700214 * Returns 0 if @work was already on a queue, non-zero otherwise.
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700215 */
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700216int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
David Howells52bad642006-11-22 14:54:01 +0000217 struct delayed_work *dwork, unsigned long delay)
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700218{
219 int ret = 0;
David Howells52bad642006-11-22 14:54:01 +0000220 struct timer_list *timer = &dwork->timer;
221 struct work_struct *work = &dwork->work;
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700222
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800223 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700224 BUG_ON(timer_pending(timer));
225 BUG_ON(!list_empty(&work->entry));
226
Oleg Nesteroved7c0fe2007-05-09 02:34:16 -0700227 /* This stores cwq for the moment, for the timer_fn */
Oleg Nesterova848e3b2007-05-09 02:34:17 -0700228 set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700229 timer->expires = jiffies + delay;
David Howells52bad642006-11-22 14:54:01 +0000230 timer->data = (unsigned long)dwork;
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700231 timer->function = delayed_work_timer_fn;
Oleg Nesterov63bc0362007-05-09 02:34:16 -0700232
233 if (unlikely(cpu >= 0))
234 add_timer_on(timer, cpu);
235 else
236 add_timer(timer);
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -0700237 ret = 1;
238 }
239 return ret;
240}
Dave Jonesae90dd52006-06-30 01:40:45 -0400241EXPORT_SYMBOL_GPL(queue_delayed_work_on);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
Arjan van de Ven858119e2006-01-14 13:20:43 -0800243static void run_workqueue(struct cpu_workqueue_struct *cwq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700245 spin_lock_irq(&cwq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 cwq->run_depth++;
247 if (cwq->run_depth > 3) {
248 /* morton gets to eat his hat */
249 printk("%s: recursion depth exceeded: %d\n",
250 __FUNCTION__, cwq->run_depth);
251 dump_stack();
252 }
253 while (!list_empty(&cwq->worklist)) {
254 struct work_struct *work = list_entry(cwq->worklist.next,
255 struct work_struct, entry);
David Howells6bb49e52006-11-22 14:54:45 +0000256 work_func_t f = work->func;
Johannes Berg4e6045f2007-10-18 23:39:55 -0700257#ifdef CONFIG_LOCKDEP
258 /*
259 * It is permissible to free the struct work_struct
260 * from inside the function that is called from it,
261 * this we need to take into account for lockdep too.
262 * To avoid bogus "held lock freed" warnings as well
263 * as problems when looking into work->lockdep_map,
264 * make a copy and use that here.
265 */
266 struct lockdep_map lockdep_map = work->lockdep_map;
267#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700269 cwq->current_work = work;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 list_del_init(cwq->worklist.next);
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700271 spin_unlock_irq(&cwq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
David Howells365970a2006-11-22 14:54:49 +0000273 BUG_ON(get_wq_data(work) != cwq);
Oleg Nesterov23b2e592007-05-09 02:34:19 -0700274 work_clear_pending(work);
Johannes Berg4e6045f2007-10-18 23:39:55 -0700275 lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
276 lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_);
David Howells65f27f32006-11-22 14:55:48 +0000277 f(work);
Johannes Berg4e6045f2007-10-18 23:39:55 -0700278 lock_release(&lockdep_map, 1, _THIS_IP_);
279 lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
Peter Zijlstrad5abe662006-12-06 20:37:26 -0800281 if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
282 printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
283 "%s/0x%08x/%d\n",
284 current->comm, preempt_count(),
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700285 task_pid_nr(current));
Peter Zijlstrad5abe662006-12-06 20:37:26 -0800286 printk(KERN_ERR " last function: ");
287 print_symbol("%s\n", (unsigned long)f);
288 debug_show_held_locks(current);
289 dump_stack();
290 }
291
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700292 spin_lock_irq(&cwq->lock);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700293 cwq->current_work = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 }
295 cwq->run_depth--;
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700296 spin_unlock_irq(&cwq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297}
298
299static int worker_thread(void *__cwq)
300{
301 struct cpu_workqueue_struct *cwq = __cwq;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700302 DEFINE_WAIT(wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700304 if (cwq->wq->freezeable)
305 set_freezable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306
307 set_user_nice(current, -5);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
Oleg Nesterov3af244332007-05-09 02:34:09 -0700309 for (;;) {
Oleg Nesterov3af244332007-05-09 02:34:09 -0700310 prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
Oleg Nesterov14441962007-05-23 13:57:57 -0700311 if (!freezing(current) &&
312 !kthread_should_stop() &&
313 list_empty(&cwq->worklist))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 schedule();
Oleg Nesterov3af244332007-05-09 02:34:09 -0700315 finish_wait(&cwq->more_work, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Oleg Nesterov85f41862007-05-09 02:34:20 -0700317 try_to_freeze();
318
Oleg Nesterov14441962007-05-23 13:57:57 -0700319 if (kthread_should_stop())
Oleg Nesterov3af244332007-05-09 02:34:09 -0700320 break;
321
322 run_workqueue(cwq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 }
Oleg Nesterov3af244332007-05-09 02:34:09 -0700324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 return 0;
326}
327
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -0700328struct wq_barrier {
329 struct work_struct work;
330 struct completion done;
331};
332
333static void wq_barrier_func(struct work_struct *work)
334{
335 struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
336 complete(&barr->done);
337}
338
Oleg Nesterov83c22522007-05-09 02:33:54 -0700339static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
340 struct wq_barrier *barr, int tail)
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -0700341{
342 INIT_WORK(&barr->work, wq_barrier_func);
343 __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work));
344
345 init_completion(&barr->done);
Oleg Nesterov83c22522007-05-09 02:33:54 -0700346
347 insert_work(cwq, &barr->work, tail);
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -0700348}
349
Oleg Nesterov14441962007-05-23 13:57:57 -0700350static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351{
Oleg Nesterov14441962007-05-23 13:57:57 -0700352 int active;
353
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 if (cwq->thread == current) {
355 /*
356 * Probably keventd trying to flush its own queue. So simply run
357 * it by hand rather than deadlocking.
358 */
359 run_workqueue(cwq);
Oleg Nesterov14441962007-05-23 13:57:57 -0700360 active = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 } else {
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -0700362 struct wq_barrier barr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
Oleg Nesterov14441962007-05-23 13:57:57 -0700364 active = 0;
Oleg Nesterov83c22522007-05-09 02:33:54 -0700365 spin_lock_irq(&cwq->lock);
366 if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
367 insert_wq_barrier(cwq, &barr, 1);
368 active = 1;
369 }
370 spin_unlock_irq(&cwq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371
Oleg Nesterovd7213042007-05-09 02:34:07 -0700372 if (active)
Oleg Nesterov83c22522007-05-09 02:33:54 -0700373 wait_for_completion(&barr.done);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 }
Oleg Nesterov14441962007-05-23 13:57:57 -0700375
376 return active;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377}
378
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700379/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 * flush_workqueue - ensure that any scheduled work has run to completion.
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700381 * @wq: workqueue to flush
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 *
383 * Forces execution of the workqueue and blocks until its completion.
384 * This is typically used in driver shutdown handlers.
385 *
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -0700386 * We sleep until all works which were queued on entry have been handled,
387 * but we are not livelocked by new incoming ones.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 *
389 * This function used to run the workqueues itself. Now we just wait for the
390 * helper threads to do it.
391 */
392void fastcall flush_workqueue(struct workqueue_struct *wq)
393{
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700394 const cpumask_t *cpu_map = wq_cpu_map(wq);
Oleg Nesterovcce1a162007-05-09 02:34:13 -0700395 int cpu;
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700396
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700397 might_sleep();
Johannes Berg4e6045f2007-10-18 23:39:55 -0700398 lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
399 lock_release(&wq->lockdep_map, 1, _THIS_IP_);
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700400 for_each_cpu_mask(cpu, *cpu_map)
401 flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402}
Dave Jonesae90dd52006-06-30 01:40:45 -0400403EXPORT_SYMBOL_GPL(flush_workqueue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700405/*
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700406 * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700407 * so this work can't be re-armed in any way.
408 */
409static int try_to_grab_pending(struct work_struct *work)
410{
411 struct cpu_workqueue_struct *cwq;
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700412 int ret = -1;
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700413
414 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work)))
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700415 return 0;
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700416
417 /*
418 * The queueing is in progress, or it is already queued. Try to
419 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
420 */
421
422 cwq = get_wq_data(work);
423 if (!cwq)
424 return ret;
425
426 spin_lock_irq(&cwq->lock);
427 if (!list_empty(&work->entry)) {
428 /*
429 * This work is queued, but perhaps we locked the wrong cwq.
430 * In that case we must see the new value after rmb(), see
431 * insert_work()->wmb().
432 */
433 smp_rmb();
434 if (cwq == get_wq_data(work)) {
435 list_del_init(&work->entry);
436 ret = 1;
437 }
438 }
439 spin_unlock_irq(&cwq->lock);
440
441 return ret;
442}
443
444static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700445 struct work_struct *work)
446{
447 struct wq_barrier barr;
448 int running = 0;
449
450 spin_lock_irq(&cwq->lock);
451 if (unlikely(cwq->current_work == work)) {
Oleg Nesterov83c22522007-05-09 02:33:54 -0700452 insert_wq_barrier(cwq, &barr, 0);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700453 running = 1;
454 }
455 spin_unlock_irq(&cwq->lock);
456
Oleg Nesterov3af244332007-05-09 02:34:09 -0700457 if (unlikely(running))
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700458 wait_for_completion(&barr.done);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700459}
460
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700461static void wait_on_work(struct work_struct *work)
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700462{
463 struct cpu_workqueue_struct *cwq;
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700464 struct workqueue_struct *wq;
465 const cpumask_t *cpu_map;
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700466 int cpu;
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700467
Oleg Nesterovf293ea92007-05-09 02:34:10 -0700468 might_sleep();
469
Johannes Berg4e6045f2007-10-18 23:39:55 -0700470 lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
471 lock_release(&work->lockdep_map, 1, _THIS_IP_);
472
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700473 cwq = get_wq_data(work);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700474 if (!cwq)
Oleg Nesterov3af244332007-05-09 02:34:09 -0700475 return;
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700476
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700477 wq = cwq->wq;
478 cpu_map = wq_cpu_map(wq);
479
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700480 for_each_cpu_mask(cpu, *cpu_map)
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700481 wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
482}
483
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700484static int __cancel_work_timer(struct work_struct *work,
485 struct timer_list* timer)
486{
487 int ret;
488
489 do {
490 ret = (timer && likely(del_timer(timer)));
491 if (!ret)
492 ret = try_to_grab_pending(work);
493 wait_on_work(work);
494 } while (unlikely(ret < 0));
495
496 work_clear_pending(work);
497 return ret;
498}
499
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700500/**
501 * cancel_work_sync - block until a work_struct's callback has terminated
502 * @work: the work which is to be flushed
503 *
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700504 * Returns true if @work was pending.
505 *
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700506 * cancel_work_sync() will cancel the work if it is queued. If the work's
507 * callback appears to be running, cancel_work_sync() will block until it
508 * has completed.
509 *
510 * It is possible to use this function if the work re-queues itself. It can
511 * cancel the work even if it migrates to another workqueue, however in that
512 * case it only guarantees that work->func() has completed on the last queued
513 * workqueue.
514 *
515 * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not
516 * pending, otherwise it goes into a busy-wait loop until the timer expires.
517 *
518 * The caller must ensure that workqueue_struct on which this work was last
519 * queued can't be destroyed before this function returns.
520 */
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700521int cancel_work_sync(struct work_struct *work)
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700522{
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700523 return __cancel_work_timer(work, NULL);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700524}
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700525EXPORT_SYMBOL_GPL(cancel_work_sync);
Oleg Nesterovb89deed2007-05-09 02:33:52 -0700526
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700527/**
Oleg Nesterovf5a421a2007-07-15 23:41:44 -0700528 * cancel_delayed_work_sync - reliably kill off a delayed work.
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700529 * @dwork: the delayed work struct
530 *
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700531 * Returns true if @dwork was pending.
532 *
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700533 * It is possible to use this function if @dwork rearms itself via queue_work()
534 * or queue_delayed_work(). See also the comment for cancel_work_sync().
535 */
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700536int cancel_delayed_work_sync(struct delayed_work *dwork)
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700537{
Oleg Nesterov1f1f6422007-07-15 23:41:44 -0700538 return __cancel_work_timer(&dwork->work, &dwork->timer);
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700539}
Oleg Nesterovf5a421a2007-07-15 23:41:44 -0700540EXPORT_SYMBOL(cancel_delayed_work_sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
Oleg Nesterov6e84d642007-05-09 02:34:46 -0700542static struct workqueue_struct *keventd_wq __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700544/**
545 * schedule_work - put work task in global workqueue
546 * @work: job to be done
547 *
548 * This puts a job in the kernel-global workqueue.
549 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550int fastcall schedule_work(struct work_struct *work)
551{
552 return queue_work(keventd_wq, work);
553}
Dave Jonesae90dd52006-06-30 01:40:45 -0400554EXPORT_SYMBOL(schedule_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700556/**
557 * schedule_delayed_work - put work task in global workqueue after delay
David Howells52bad642006-11-22 14:54:01 +0000558 * @dwork: job to be done
559 * @delay: number of jiffies to wait or 0 for immediate execution
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700560 *
561 * After waiting for a given time this puts a job in the kernel-global
562 * workqueue.
563 */
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800564int fastcall schedule_delayed_work(struct delayed_work *dwork,
565 unsigned long delay)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566{
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800567 timer_stats_timer_set_start_info(&dwork->timer);
David Howells52bad642006-11-22 14:54:01 +0000568 return queue_delayed_work(keventd_wq, dwork, delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569}
Dave Jonesae90dd52006-06-30 01:40:45 -0400570EXPORT_SYMBOL(schedule_delayed_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700572/**
573 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
574 * @cpu: cpu to use
David Howells52bad642006-11-22 14:54:01 +0000575 * @dwork: job to be done
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -0700576 * @delay: number of jiffies to wait
577 *
578 * After waiting for a given time this puts a job in the kernel-global
579 * workqueue on the specified CPU.
580 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581int schedule_delayed_work_on(int cpu,
David Howells52bad642006-11-22 14:54:01 +0000582 struct delayed_work *dwork, unsigned long delay)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583{
David Howells52bad642006-11-22 14:54:01 +0000584 return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585}
Dave Jonesae90dd52006-06-30 01:40:45 -0400586EXPORT_SYMBOL(schedule_delayed_work_on);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587
Andrew Mortonb6136772006-06-25 05:47:49 -0700588/**
589 * schedule_on_each_cpu - call a function on each online CPU from keventd
590 * @func: the function to call
Andrew Mortonb6136772006-06-25 05:47:49 -0700591 *
592 * Returns zero on success.
593 * Returns -ve errno on failure.
594 *
595 * Appears to be racy against CPU hotplug.
596 *
597 * schedule_on_each_cpu() is very slow.
598 */
David Howells65f27f32006-11-22 14:55:48 +0000599int schedule_on_each_cpu(work_func_t func)
Christoph Lameter15316ba2006-01-08 01:00:43 -0800600{
601 int cpu;
Andrew Mortonb6136772006-06-25 05:47:49 -0700602 struct work_struct *works;
Christoph Lameter15316ba2006-01-08 01:00:43 -0800603
Andrew Mortonb6136772006-06-25 05:47:49 -0700604 works = alloc_percpu(struct work_struct);
605 if (!works)
Christoph Lameter15316ba2006-01-08 01:00:43 -0800606 return -ENOMEM;
Andrew Mortonb6136772006-06-25 05:47:49 -0700607
Andrew Mortone18f3ff2007-05-09 02:33:50 -0700608 preempt_disable(); /* CPU hotplug */
Christoph Lameter15316ba2006-01-08 01:00:43 -0800609 for_each_online_cpu(cpu) {
Ingo Molnar9bfb1832006-12-18 20:05:09 +0100610 struct work_struct *work = per_cpu_ptr(works, cpu);
611
612 INIT_WORK(work, func);
613 set_bit(WORK_STRUCT_PENDING, work_data_bits(work));
614 __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work);
Christoph Lameter15316ba2006-01-08 01:00:43 -0800615 }
Andrew Mortone18f3ff2007-05-09 02:33:50 -0700616 preempt_enable();
Christoph Lameter15316ba2006-01-08 01:00:43 -0800617 flush_workqueue(keventd_wq);
Andrew Mortonb6136772006-06-25 05:47:49 -0700618 free_percpu(works);
Christoph Lameter15316ba2006-01-08 01:00:43 -0800619 return 0;
620}
621
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622void flush_scheduled_work(void)
623{
624 flush_workqueue(keventd_wq);
625}
Dave Jonesae90dd52006-06-30 01:40:45 -0400626EXPORT_SYMBOL(flush_scheduled_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
628/**
James Bottomley1fa44ec2006-02-23 12:43:43 -0600629 * execute_in_process_context - reliably execute the routine with user context
630 * @fn: the function to execute
James Bottomley1fa44ec2006-02-23 12:43:43 -0600631 * @ew: guaranteed storage for the execute work structure (must
632 * be available when the work executes)
633 *
634 * Executes the function immediately if process context is available,
635 * otherwise schedules the function for delayed execution.
636 *
637 * Returns: 0 - function was executed
638 * 1 - function was scheduled for execution
639 */
David Howells65f27f32006-11-22 14:55:48 +0000640int execute_in_process_context(work_func_t fn, struct execute_work *ew)
James Bottomley1fa44ec2006-02-23 12:43:43 -0600641{
642 if (!in_interrupt()) {
David Howells65f27f32006-11-22 14:55:48 +0000643 fn(&ew->work);
James Bottomley1fa44ec2006-02-23 12:43:43 -0600644 return 0;
645 }
646
David Howells65f27f32006-11-22 14:55:48 +0000647 INIT_WORK(&ew->work, fn);
James Bottomley1fa44ec2006-02-23 12:43:43 -0600648 schedule_work(&ew->work);
649
650 return 1;
651}
652EXPORT_SYMBOL_GPL(execute_in_process_context);
653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654int keventd_up(void)
655{
656 return keventd_wq != NULL;
657}
658
659int current_is_keventd(void)
660{
661 struct cpu_workqueue_struct *cwq;
Hugh Dickinsd2437692007-08-27 16:06:19 +0100662 int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 int ret = 0;
664
665 BUG_ON(!keventd_wq);
666
Christoph Lameter89ada672005-10-30 15:01:59 -0800667 cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 if (current == cwq->thread)
669 ret = 1;
670
671 return ret;
672
673}
674
Oleg Nesterov3af244332007-05-09 02:34:09 -0700675static struct cpu_workqueue_struct *
676init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677{
Christoph Lameter89ada672005-10-30 15:01:59 -0800678 struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
Oleg Nesterov3af244332007-05-09 02:34:09 -0700680 cwq->wq = wq;
681 spin_lock_init(&cwq->lock);
682 INIT_LIST_HEAD(&cwq->worklist);
683 init_waitqueue_head(&cwq->more_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684
Oleg Nesterov3af244332007-05-09 02:34:09 -0700685 return cwq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686}
687
Oleg Nesterov3af244332007-05-09 02:34:09 -0700688static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689{
Oleg Nesterov3af244332007-05-09 02:34:09 -0700690 struct workqueue_struct *wq = cwq->wq;
691 const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
692 struct task_struct *p;
693
694 p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
695 /*
696 * Nobody can add the work_struct to this cwq,
697 * if (caller is __create_workqueue)
698 * nobody should see this wq
699 * else // caller is CPU_UP_PREPARE
700 * cpu is not on cpu_online_map
701 * so we can abort safely.
702 */
703 if (IS_ERR(p))
704 return PTR_ERR(p);
705
706 cwq->thread = p;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700707
708 return 0;
709}
710
Oleg Nesterov06ba38a2007-05-09 02:34:15 -0700711static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
712{
713 struct task_struct *p = cwq->thread;
714
715 if (p != NULL) {
716 if (cpu >= 0)
717 kthread_bind(p, cpu);
718 wake_up_process(p);
719 }
720}
721
Johannes Berg4e6045f2007-10-18 23:39:55 -0700722struct workqueue_struct *__create_workqueue_key(const char *name,
723 int singlethread,
724 int freezeable,
Johannes Bergeb13ba82008-01-16 09:51:58 +0100725 struct lock_class_key *key,
726 const char *lock_name)
Oleg Nesterov3af244332007-05-09 02:34:09 -0700727{
728 struct workqueue_struct *wq;
729 struct cpu_workqueue_struct *cwq;
730 int err = 0, cpu;
731
732 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
733 if (!wq)
734 return NULL;
735
736 wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
737 if (!wq->cpu_wq) {
738 kfree(wq);
739 return NULL;
740 }
741
742 wq->name = name;
Johannes Bergeb13ba82008-01-16 09:51:58 +0100743 lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
Oleg Nesterovcce1a162007-05-09 02:34:13 -0700744 wq->singlethread = singlethread;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700745 wq->freezeable = freezeable;
Oleg Nesterovcce1a162007-05-09 02:34:13 -0700746 INIT_LIST_HEAD(&wq->list);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700747
748 if (singlethread) {
Oleg Nesterov3af244332007-05-09 02:34:09 -0700749 cwq = init_cpu_workqueue(wq, singlethread_cpu);
750 err = create_workqueue_thread(cwq, singlethread_cpu);
Oleg Nesterov06ba38a2007-05-09 02:34:15 -0700751 start_workqueue_thread(cwq, -1);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700752 } else {
753 mutex_lock(&workqueue_mutex);
754 list_add(&wq->list, &workqueues);
755
756 for_each_possible_cpu(cpu) {
757 cwq = init_cpu_workqueue(wq, cpu);
758 if (err || !cpu_online(cpu))
759 continue;
760 err = create_workqueue_thread(cwq, cpu);
Oleg Nesterov06ba38a2007-05-09 02:34:15 -0700761 start_workqueue_thread(cwq, cpu);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700762 }
763 mutex_unlock(&workqueue_mutex);
764 }
765
766 if (err) {
767 destroy_workqueue(wq);
768 wq = NULL;
769 }
770 return wq;
771}
Johannes Berg4e6045f2007-10-18 23:39:55 -0700772EXPORT_SYMBOL_GPL(__create_workqueue_key);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700773
774static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
775{
Oleg Nesterov14441962007-05-23 13:57:57 -0700776 /*
777 * Our caller is either destroy_workqueue() or CPU_DEAD,
778 * workqueue_mutex protects cwq->thread
779 */
780 if (cwq->thread == NULL)
781 return;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700782
Johannes Berg4e6045f2007-10-18 23:39:55 -0700783 lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
784 lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
785
Oleg Nesterov13c22162007-07-17 04:03:55 -0700786 flush_cpu_workqueue(cwq);
Oleg Nesterov14441962007-05-23 13:57:57 -0700787 /*
Oleg Nesterov13c22162007-07-17 04:03:55 -0700788 * If the caller is CPU_DEAD and cwq->worklist was not empty,
789 * a concurrent flush_workqueue() can insert a barrier after us.
790 * However, in that case run_workqueue() won't return and check
791 * kthread_should_stop() until it flushes all work_struct's.
Oleg Nesterov14441962007-05-23 13:57:57 -0700792 * When ->worklist becomes empty it is safe to exit because no
793 * more work_structs can be queued on this cwq: flush_workqueue
794 * checks list_empty(), and a "normal" queue_work() can't use
795 * a dead CPU.
796 */
Oleg Nesterov14441962007-05-23 13:57:57 -0700797 kthread_stop(cwq->thread);
798 cwq->thread = NULL;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700799}
800
801/**
802 * destroy_workqueue - safely terminate a workqueue
803 * @wq: target workqueue
804 *
805 * Safely destroy a workqueue. All work currently pending will be done first.
806 */
807void destroy_workqueue(struct workqueue_struct *wq)
808{
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700809 const cpumask_t *cpu_map = wq_cpu_map(wq);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700810 struct cpu_workqueue_struct *cwq;
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700811 int cpu;
Oleg Nesterov3af244332007-05-09 02:34:09 -0700812
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700813 mutex_lock(&workqueue_mutex);
814 list_del(&wq->list);
815 mutex_unlock(&workqueue_mutex);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700816
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700817 for_each_cpu_mask(cpu, *cpu_map) {
818 cwq = per_cpu_ptr(wq->cpu_wq, cpu);
819 cleanup_workqueue_thread(cwq, cpu);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700820 }
821
822 free_percpu(wq->cpu_wq);
823 kfree(wq);
824}
825EXPORT_SYMBOL_GPL(destroy_workqueue);
826
827static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
828 unsigned long action,
829 void *hcpu)
830{
831 unsigned int cpu = (unsigned long)hcpu;
832 struct cpu_workqueue_struct *cwq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 struct workqueue_struct *wq;
834
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -0700835 action &= ~CPU_TASKS_FROZEN;
836
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 switch (action) {
Oleg Nesterov3af244332007-05-09 02:34:09 -0700838 case CPU_LOCK_ACQUIRE:
839 mutex_lock(&workqueue_mutex);
840 return NOTIFY_OK;
841
842 case CPU_LOCK_RELEASE:
843 mutex_unlock(&workqueue_mutex);
844 return NOTIFY_OK;
845
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 case CPU_UP_PREPARE:
Oleg Nesterov3af244332007-05-09 02:34:09 -0700847 cpu_set(cpu, cpu_populated_map);
848 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849
Oleg Nesterov3af244332007-05-09 02:34:09 -0700850 list_for_each_entry(wq, &workqueues, list) {
851 cwq = per_cpu_ptr(wq->cpu_wq, cpu);
Christoph Lameter89ada672005-10-30 15:01:59 -0800852
Oleg Nesterov3af244332007-05-09 02:34:09 -0700853 switch (action) {
854 case CPU_UP_PREPARE:
855 if (!create_workqueue_thread(cwq, cpu))
856 break;
857 printk(KERN_ERR "workqueue for %i failed\n", cpu);
858 return NOTIFY_BAD;
859
860 case CPU_ONLINE:
Oleg Nesterov06ba38a2007-05-09 02:34:15 -0700861 start_workqueue_thread(cwq, cpu);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700862 break;
863
864 case CPU_UP_CANCELED:
Oleg Nesterov06ba38a2007-05-09 02:34:15 -0700865 start_workqueue_thread(cwq, -1);
Oleg Nesterov3af244332007-05-09 02:34:09 -0700866 case CPU_DEAD:
867 cleanup_workqueue_thread(cwq, cpu);
868 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 }
871
872 return NOTIFY_OK;
873}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874
Oleg Nesterovc12920d2007-05-09 02:34:14 -0700875void __init init_workqueues(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876{
Oleg Nesterov3af244332007-05-09 02:34:09 -0700877 cpu_populated_map = cpu_online_map;
Nathan Lynchf756d5e2006-01-08 01:05:12 -0800878 singlethread_cpu = first_cpu(cpu_possible_map);
Oleg Nesterovb1f4ec172007-05-09 02:34:12 -0700879 cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 hotcpu_notifier(workqueue_cpu_callback, 0);
881 keventd_wq = create_workqueue("events");
882 BUG_ON(!keventd_wq);
883}