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v5.4
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2007 Oracle.  All rights reserved.
  4 * Copyright (C) 2014 Fujitsu.  All rights reserved.
  5 */
  6
  7#include <linux/kthread.h>
  8#include <linux/slab.h>
  9#include <linux/list.h>
 10#include <linux/spinlock.h>
 11#include <linux/freezer.h>
 
 12#include "async-thread.h"
 13#include "ctree.h"
 14
 15enum {
 16	WORK_DONE_BIT,
 17	WORK_ORDER_DONE_BIT,
 18	WORK_HIGH_PRIO_BIT,
 19};
 20
 21#define NO_THRESHOLD (-1)
 22#define DFT_THRESHOLD (32)
 23
 24struct __btrfs_workqueue {
 25	struct workqueue_struct *normal_wq;
 26
 27	/* File system this workqueue services */
 28	struct btrfs_fs_info *fs_info;
 29
 30	/* List head pointing to ordered work list */
 31	struct list_head ordered_list;
 32
 33	/* Spinlock for ordered_list */
 34	spinlock_t list_lock;
 35
 36	/* Thresholding related variants */
 37	atomic_t pending;
 38
 39	/* Up limit of concurrency workers */
 40	int limit_active;
 41
 42	/* Current number of concurrency workers */
 43	int current_active;
 44
 45	/* Threshold to change current_active */
 46	int thresh;
 47	unsigned int count;
 48	spinlock_t thres_lock;
 49};
 50
 51struct btrfs_workqueue {
 52	struct __btrfs_workqueue *normal;
 53	struct __btrfs_workqueue *high;
 54};
 55
 56static void normal_work_helper(struct btrfs_work *work);
 57
 58#define BTRFS_WORK_HELPER(name)					\
 59noinline_for_stack void btrfs_##name(struct work_struct *arg)		\
 60{									\
 61	struct btrfs_work *work = container_of(arg, struct btrfs_work,	\
 62					       normal_work);		\
 63	normal_work_helper(work);					\
 64}
 65
 66struct btrfs_fs_info *
 67btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
 68{
 69	return wq->fs_info;
 70}
 71
 72struct btrfs_fs_info *
 73btrfs_work_owner(const struct btrfs_work *work)
 74{
 75	return work->wq->fs_info;
 76}
 77
 78bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq)
 79{
 80	/*
 81	 * We could compare wq->normal->pending with num_online_cpus()
 82	 * to support "thresh == NO_THRESHOLD" case, but it requires
 83	 * moving up atomic_inc/dec in thresh_queue/exec_hook. Let's
 84	 * postpone it until someone needs the support of that case.
 85	 */
 86	if (wq->normal->thresh == NO_THRESHOLD)
 87		return false;
 88
 89	return atomic_read(&wq->normal->pending) > wq->normal->thresh * 2;
 
 
 
 
 
 
 
 
 
 
 90}
 91
 92BTRFS_WORK_HELPER(worker_helper);
 93BTRFS_WORK_HELPER(delalloc_helper);
 94BTRFS_WORK_HELPER(flush_delalloc_helper);
 95BTRFS_WORK_HELPER(cache_helper);
 96BTRFS_WORK_HELPER(submit_helper);
 97BTRFS_WORK_HELPER(fixup_helper);
 98BTRFS_WORK_HELPER(endio_helper);
 99BTRFS_WORK_HELPER(endio_meta_helper);
100BTRFS_WORK_HELPER(endio_meta_write_helper);
101BTRFS_WORK_HELPER(endio_raid56_helper);
102BTRFS_WORK_HELPER(endio_repair_helper);
103BTRFS_WORK_HELPER(rmw_helper);
104BTRFS_WORK_HELPER(endio_write_helper);
105BTRFS_WORK_HELPER(freespace_write_helper);
106BTRFS_WORK_HELPER(delayed_meta_helper);
107BTRFS_WORK_HELPER(readahead_helper);
108BTRFS_WORK_HELPER(qgroup_rescan_helper);
109BTRFS_WORK_HELPER(extent_refs_helper);
110BTRFS_WORK_HELPER(scrub_helper);
111BTRFS_WORK_HELPER(scrubwrc_helper);
112BTRFS_WORK_HELPER(scrubnc_helper);
113BTRFS_WORK_HELPER(scrubparity_helper);
114
115static struct __btrfs_workqueue *
116__btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info, const char *name,
117			unsigned int flags, int limit_active, int thresh)
118{
119	struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
120
121	if (!ret)
122		return NULL;
123
124	ret->fs_info = fs_info;
 
125	ret->limit_active = limit_active;
126	atomic_set(&ret->pending, 0);
127	if (thresh == 0)
128		thresh = DFT_THRESHOLD;
129	/* For low threshold, disabling threshold is a better choice */
130	if (thresh < DFT_THRESHOLD) {
131		ret->current_active = limit_active;
132		ret->thresh = NO_THRESHOLD;
133	} else {
134		/*
135		 * For threshold-able wq, let its concurrency grow on demand.
136		 * Use minimal max_active at alloc time to reduce resource
137		 * usage.
138		 */
139		ret->current_active = 1;
140		ret->thresh = thresh;
141	}
142
143	if (flags & WQ_HIGHPRI)
144		ret->normal_wq = alloc_workqueue("btrfs-%s-high", flags,
145						 ret->current_active, name);
146	else
147		ret->normal_wq = alloc_workqueue("btrfs-%s", flags,
148						 ret->current_active, name);
149	if (!ret->normal_wq) {
150		kfree(ret);
151		return NULL;
152	}
153
154	INIT_LIST_HEAD(&ret->ordered_list);
155	spin_lock_init(&ret->list_lock);
156	spin_lock_init(&ret->thres_lock);
157	trace_btrfs_workqueue_alloc(ret, name, flags & WQ_HIGHPRI);
158	return ret;
159}
160
161static inline void
162__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
163
164struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
165					      const char *name,
166					      unsigned int flags,
167					      int limit_active,
168					      int thresh)
169{
170	struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
171
 
172	if (!ret)
173		return NULL;
174
175	ret->normal = __btrfs_alloc_workqueue(fs_info, name,
176					      flags & ~WQ_HIGHPRI,
177					      limit_active, thresh);
178	if (!ret->normal) {
 
 
 
 
 
179		kfree(ret);
180		return NULL;
181	}
182
183	if (flags & WQ_HIGHPRI) {
184		ret->high = __btrfs_alloc_workqueue(fs_info, name, flags,
185						    limit_active, thresh);
186		if (!ret->high) {
187			__btrfs_destroy_workqueue(ret->normal);
188			kfree(ret);
189			return NULL;
190		}
191	}
192	return ret;
193}
194
195/*
196 * Hook for threshold which will be called in btrfs_queue_work.
197 * This hook WILL be called in IRQ handler context,
198 * so workqueue_set_max_active MUST NOT be called in this hook
199 */
200static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
201{
202	if (wq->thresh == NO_THRESHOLD)
203		return;
204	atomic_inc(&wq->pending);
205}
206
207/*
208 * Hook for threshold which will be called before executing the work,
209 * This hook is called in kthread content.
210 * So workqueue_set_max_active is called here.
211 */
212static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
213{
214	int new_current_active;
215	long pending;
216	int need_change = 0;
217
218	if (wq->thresh == NO_THRESHOLD)
219		return;
220
221	atomic_dec(&wq->pending);
222	spin_lock(&wq->thres_lock);
223	/*
224	 * Use wq->count to limit the calling frequency of
225	 * workqueue_set_max_active.
226	 */
227	wq->count++;
228	wq->count %= (wq->thresh / 4);
229	if (!wq->count)
230		goto  out;
231	new_current_active = wq->current_active;
232
233	/*
234	 * pending may be changed later, but it's OK since we really
235	 * don't need it so accurate to calculate new_max_active.
236	 */
237	pending = atomic_read(&wq->pending);
238	if (pending > wq->thresh)
239		new_current_active++;
240	if (pending < wq->thresh / 2)
241		new_current_active--;
242	new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
243	if (new_current_active != wq->current_active)  {
244		need_change = 1;
245		wq->current_active = new_current_active;
246	}
247out:
248	spin_unlock(&wq->thres_lock);
249
250	if (need_change) {
251		workqueue_set_max_active(wq->normal_wq, wq->current_active);
252	}
253}
254
255static void run_ordered_work(struct __btrfs_workqueue *wq)
 
256{
257	struct list_head *list = &wq->ordered_list;
258	struct btrfs_work *work;
259	spinlock_t *lock = &wq->list_lock;
260	unsigned long flags;
 
261
262	while (1) {
263		void *wtag;
264
265		spin_lock_irqsave(lock, flags);
266		if (list_empty(list))
267			break;
268		work = list_entry(list->next, struct btrfs_work,
269				  ordered_list);
270		if (!test_bit(WORK_DONE_BIT, &work->flags))
271			break;
 
 
 
 
 
 
 
272
273		/*
274		 * we are going to call the ordered done function, but
275		 * we leave the work item on the list as a barrier so
276		 * that later work items that are done don't have their
277		 * functions called before this one returns
278		 */
279		if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
280			break;
281		trace_btrfs_ordered_sched(work);
282		spin_unlock_irqrestore(lock, flags);
283		work->ordered_func(work);
284
285		/* now take the lock again and drop our item from the list */
286		spin_lock_irqsave(lock, flags);
287		list_del(&work->ordered_list);
288		spin_unlock_irqrestore(lock, flags);
289
290		/*
291		 * We don't want to call the ordered free functions with the
292		 * lock held though. Save the work as tag for the trace event,
293		 * because the callback could free the structure.
294		 */
295		wtag = work;
296		work->ordered_free(work);
297		trace_btrfs_all_work_done(wq->fs_info, wtag);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
298	}
299	spin_unlock_irqrestore(lock, flags);
 
 
 
 
 
 
300}
301
302static void normal_work_helper(struct btrfs_work *work)
303{
304	struct __btrfs_workqueue *wq;
305	void *wtag;
 
306	int need_order = 0;
307
308	/*
309	 * We should not touch things inside work in the following cases:
310	 * 1) after work->func() if it has no ordered_free
311	 *    Since the struct is freed in work->func().
312	 * 2) after setting WORK_DONE_BIT
313	 *    The work may be freed in other threads almost instantly.
314	 * So we save the needed things here.
315	 */
316	if (work->ordered_func)
317		need_order = 1;
318	wq = work->wq;
319	/* Safe for tracepoints in case work gets freed by the callback */
320	wtag = work;
321
322	trace_btrfs_work_sched(work);
323	thresh_exec_hook(wq);
324	work->func(work);
325	if (need_order) {
 
 
 
 
 
 
 
326		set_bit(WORK_DONE_BIT, &work->flags);
327		run_ordered_work(wq);
 
 
 
328	}
329	if (!need_order)
330		trace_btrfs_all_work_done(wq->fs_info, wtag);
331}
332
333void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t uniq_func,
334		     btrfs_func_t func,
335		     btrfs_func_t ordered_func,
336		     btrfs_func_t ordered_free)
337{
338	work->func = func;
339	work->ordered_func = ordered_func;
340	work->ordered_free = ordered_free;
341	INIT_WORK(&work->normal_work, uniq_func);
342	INIT_LIST_HEAD(&work->ordered_list);
343	work->flags = 0;
344}
345
346static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq,
347				      struct btrfs_work *work)
348{
349	unsigned long flags;
350
351	work->wq = wq;
352	thresh_queue_hook(wq);
353	if (work->ordered_func) {
354		spin_lock_irqsave(&wq->list_lock, flags);
355		list_add_tail(&work->ordered_list, &wq->ordered_list);
356		spin_unlock_irqrestore(&wq->list_lock, flags);
357	}
358	trace_btrfs_work_queued(work);
359	queue_work(wq->normal_wq, &work->normal_work);
360}
361
362void btrfs_queue_work(struct btrfs_workqueue *wq,
363		      struct btrfs_work *work)
364{
365	struct __btrfs_workqueue *dest_wq;
366
367	if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
368		dest_wq = wq->high;
369	else
370		dest_wq = wq->normal;
371	__btrfs_queue_work(dest_wq, work);
372}
373
374static inline void
375__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq)
376{
377	destroy_workqueue(wq->normal_wq);
378	trace_btrfs_workqueue_destroy(wq);
379	kfree(wq);
380}
381
382void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
383{
384	if (!wq)
385		return;
386	if (wq->high)
387		__btrfs_destroy_workqueue(wq->high);
388	__btrfs_destroy_workqueue(wq->normal);
389	kfree(wq);
390}
391
392void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
393{
394	if (!wq)
395		return;
396	wq->normal->limit_active = limit_active;
397	if (wq->high)
398		wq->high->limit_active = limit_active;
399}
400
401void btrfs_set_work_high_priority(struct btrfs_work *work)
402{
403	set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
404}
v6.8
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2007 Oracle.  All rights reserved.
  4 * Copyright (C) 2014 Fujitsu.  All rights reserved.
  5 */
  6
  7#include <linux/kthread.h>
  8#include <linux/slab.h>
  9#include <linux/list.h>
 10#include <linux/spinlock.h>
 11#include <linux/freezer.h>
 12#include <trace/events/btrfs.h>
 13#include "async-thread.h"
 14#include "ctree.h"
 15
 16enum {
 17	WORK_DONE_BIT,
 18	WORK_ORDER_DONE_BIT,
 
 19};
 20
 21#define NO_THRESHOLD (-1)
 22#define DFT_THRESHOLD (32)
 23
 24struct btrfs_workqueue {
 25	struct workqueue_struct *normal_wq;
 26
 27	/* File system this workqueue services */
 28	struct btrfs_fs_info *fs_info;
 29
 30	/* List head pointing to ordered work list */
 31	struct list_head ordered_list;
 32
 33	/* Spinlock for ordered_list */
 34	spinlock_t list_lock;
 35
 36	/* Thresholding related variants */
 37	atomic_t pending;
 38
 39	/* Up limit of concurrency workers */
 40	int limit_active;
 41
 42	/* Current number of concurrency workers */
 43	int current_active;
 44
 45	/* Threshold to change current_active */
 46	int thresh;
 47	unsigned int count;
 48	spinlock_t thres_lock;
 49};
 50
 51struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct btrfs_workqueue *wq)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 52{
 53	return wq->fs_info;
 54}
 55
 56struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work)
 
 57{
 58	return work->wq->fs_info;
 59}
 60
 61bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq)
 62{
 63	/*
 64	 * We could compare wq->pending with num_online_cpus()
 65	 * to support "thresh == NO_THRESHOLD" case, but it requires
 66	 * moving up atomic_inc/dec in thresh_queue/exec_hook. Let's
 67	 * postpone it until someone needs the support of that case.
 68	 */
 69	if (wq->thresh == NO_THRESHOLD)
 70		return false;
 71
 72	return atomic_read(&wq->pending) > wq->thresh * 2;
 73}
 74
 75static void btrfs_init_workqueue(struct btrfs_workqueue *wq,
 76				 struct btrfs_fs_info *fs_info)
 77{
 78	wq->fs_info = fs_info;
 79	atomic_set(&wq->pending, 0);
 80	INIT_LIST_HEAD(&wq->ordered_list);
 81	spin_lock_init(&wq->list_lock);
 82	spin_lock_init(&wq->thres_lock);
 83}
 84
 85struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
 86					      const char *name, unsigned int flags,
 87					      int limit_active, int thresh)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 88{
 89	struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
 90
 91	if (!ret)
 92		return NULL;
 93
 94	btrfs_init_workqueue(ret, fs_info);
 95
 96	ret->limit_active = limit_active;
 
 97	if (thresh == 0)
 98		thresh = DFT_THRESHOLD;
 99	/* For low threshold, disabling threshold is a better choice */
100	if (thresh < DFT_THRESHOLD) {
101		ret->current_active = limit_active;
102		ret->thresh = NO_THRESHOLD;
103	} else {
104		/*
105		 * For threshold-able wq, let its concurrency grow on demand.
106		 * Use minimal max_active at alloc time to reduce resource
107		 * usage.
108		 */
109		ret->current_active = 1;
110		ret->thresh = thresh;
111	}
112
113	ret->normal_wq = alloc_workqueue("btrfs-%s", flags, ret->current_active,
114					 name);
 
 
 
 
115	if (!ret->normal_wq) {
116		kfree(ret);
117		return NULL;
118	}
119
120	trace_btrfs_workqueue_alloc(ret, name);
 
 
 
121	return ret;
122}
123
124struct btrfs_workqueue *btrfs_alloc_ordered_workqueue(
125				struct btrfs_fs_info *fs_info, const char *name,
126				unsigned int flags)
 
 
 
 
 
127{
128	struct btrfs_workqueue *ret;
129
130	ret = kzalloc(sizeof(*ret), GFP_KERNEL);
131	if (!ret)
132		return NULL;
133
134	btrfs_init_workqueue(ret, fs_info);
135
136	/* Ordered workqueues don't allow @max_active adjustments. */
137	ret->limit_active = 1;
138	ret->current_active = 1;
139	ret->thresh = NO_THRESHOLD;
140
141	ret->normal_wq = alloc_ordered_workqueue("btrfs-%s", flags, name);
142	if (!ret->normal_wq) {
143		kfree(ret);
144		return NULL;
145	}
146
147	trace_btrfs_workqueue_alloc(ret, name);
 
 
 
 
 
 
 
 
148	return ret;
149}
150
151/*
152 * Hook for threshold which will be called in btrfs_queue_work.
153 * This hook WILL be called in IRQ handler context,
154 * so workqueue_set_max_active MUST NOT be called in this hook
155 */
156static inline void thresh_queue_hook(struct btrfs_workqueue *wq)
157{
158	if (wq->thresh == NO_THRESHOLD)
159		return;
160	atomic_inc(&wq->pending);
161}
162
163/*
164 * Hook for threshold which will be called before executing the work,
165 * This hook is called in kthread content.
166 * So workqueue_set_max_active is called here.
167 */
168static inline void thresh_exec_hook(struct btrfs_workqueue *wq)
169{
170	int new_current_active;
171	long pending;
172	int need_change = 0;
173
174	if (wq->thresh == NO_THRESHOLD)
175		return;
176
177	atomic_dec(&wq->pending);
178	spin_lock(&wq->thres_lock);
179	/*
180	 * Use wq->count to limit the calling frequency of
181	 * workqueue_set_max_active.
182	 */
183	wq->count++;
184	wq->count %= (wq->thresh / 4);
185	if (!wq->count)
186		goto  out;
187	new_current_active = wq->current_active;
188
189	/*
190	 * pending may be changed later, but it's OK since we really
191	 * don't need it so accurate to calculate new_max_active.
192	 */
193	pending = atomic_read(&wq->pending);
194	if (pending > wq->thresh)
195		new_current_active++;
196	if (pending < wq->thresh / 2)
197		new_current_active--;
198	new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
199	if (new_current_active != wq->current_active)  {
200		need_change = 1;
201		wq->current_active = new_current_active;
202	}
203out:
204	spin_unlock(&wq->thres_lock);
205
206	if (need_change) {
207		workqueue_set_max_active(wq->normal_wq, wq->current_active);
208	}
209}
210
211static void run_ordered_work(struct btrfs_workqueue *wq,
212			     struct btrfs_work *self)
213{
214	struct list_head *list = &wq->ordered_list;
215	struct btrfs_work *work;
216	spinlock_t *lock = &wq->list_lock;
217	unsigned long flags;
218	bool free_self = false;
219
220	while (1) {
 
 
221		spin_lock_irqsave(lock, flags);
222		if (list_empty(list))
223			break;
224		work = list_entry(list->next, struct btrfs_work,
225				  ordered_list);
226		if (!test_bit(WORK_DONE_BIT, &work->flags))
227			break;
228		/*
229		 * Orders all subsequent loads after reading WORK_DONE_BIT,
230		 * paired with the smp_mb__before_atomic in btrfs_work_helper
231		 * this guarantees that the ordered function will see all
232		 * updates from ordinary work function.
233		 */
234		smp_rmb();
235
236		/*
237		 * we are going to call the ordered done function, but
238		 * we leave the work item on the list as a barrier so
239		 * that later work items that are done don't have their
240		 * functions called before this one returns
241		 */
242		if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
243			break;
244		trace_btrfs_ordered_sched(work);
245		spin_unlock_irqrestore(lock, flags);
246		work->ordered_func(work, false);
247
248		/* now take the lock again and drop our item from the list */
249		spin_lock_irqsave(lock, flags);
250		list_del(&work->ordered_list);
251		spin_unlock_irqrestore(lock, flags);
252
253		if (work == self) {
254			/*
255			 * This is the work item that the worker is currently
256			 * executing.
257			 *
258			 * The kernel workqueue code guarantees non-reentrancy
259			 * of work items. I.e., if a work item with the same
260			 * address and work function is queued twice, the second
261			 * execution is blocked until the first one finishes. A
262			 * work item may be freed and recycled with the same
263			 * work function; the workqueue code assumes that the
264			 * original work item cannot depend on the recycled work
265			 * item in that case (see find_worker_executing_work()).
266			 *
267			 * Note that different types of Btrfs work can depend on
268			 * each other, and one type of work on one Btrfs
269			 * filesystem may even depend on the same type of work
270			 * on another Btrfs filesystem via, e.g., a loop device.
271			 * Therefore, we must not allow the current work item to
272			 * be recycled until we are really done, otherwise we
273			 * break the above assumption and can deadlock.
274			 */
275			free_self = true;
276		} else {
277			/*
278			 * We don't want to call the ordered free functions with
279			 * the lock held.
280			 */
281			work->ordered_func(work, true);
282			/* NB: work must not be dereferenced past this point. */
283			trace_btrfs_all_work_done(wq->fs_info, work);
284		}
285	}
286	spin_unlock_irqrestore(lock, flags);
287
288	if (free_self) {
289		self->ordered_func(self, true);
290		/* NB: self must not be dereferenced past this point. */
291		trace_btrfs_all_work_done(wq->fs_info, self);
292	}
293}
294
295static void btrfs_work_helper(struct work_struct *normal_work)
296{
297	struct btrfs_work *work = container_of(normal_work, struct btrfs_work,
298					       normal_work);
299	struct btrfs_workqueue *wq = work->wq;
300	int need_order = 0;
301
302	/*
303	 * We should not touch things inside work in the following cases:
304	 * 1) after work->func() if it has no ordered_func(..., true) to free
305	 *    Since the struct is freed in work->func().
306	 * 2) after setting WORK_DONE_BIT
307	 *    The work may be freed in other threads almost instantly.
308	 * So we save the needed things here.
309	 */
310	if (work->ordered_func)
311		need_order = 1;
 
 
 
312
313	trace_btrfs_work_sched(work);
314	thresh_exec_hook(wq);
315	work->func(work);
316	if (need_order) {
317		/*
318		 * Ensures all memory accesses done in the work function are
319		 * ordered before setting the WORK_DONE_BIT. Ensuring the thread
320		 * which is going to executed the ordered work sees them.
321		 * Pairs with the smp_rmb in run_ordered_work.
322		 */
323		smp_mb__before_atomic();
324		set_bit(WORK_DONE_BIT, &work->flags);
325		run_ordered_work(wq, work);
326	} else {
327		/* NB: work must not be dereferenced past this point. */
328		trace_btrfs_all_work_done(wq->fs_info, work);
329	}
 
 
330}
331
332void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func,
333		     btrfs_ordered_func_t ordered_func)
 
 
334{
335	work->func = func;
336	work->ordered_func = ordered_func;
337	INIT_WORK(&work->normal_work, btrfs_work_helper);
 
338	INIT_LIST_HEAD(&work->ordered_list);
339	work->flags = 0;
340}
341
342void btrfs_queue_work(struct btrfs_workqueue *wq, struct btrfs_work *work)
 
343{
344	unsigned long flags;
345
346	work->wq = wq;
347	thresh_queue_hook(wq);
348	if (work->ordered_func) {
349		spin_lock_irqsave(&wq->list_lock, flags);
350		list_add_tail(&work->ordered_list, &wq->ordered_list);
351		spin_unlock_irqrestore(&wq->list_lock, flags);
352	}
353	trace_btrfs_work_queued(work);
354	queue_work(wq->normal_wq, &work->normal_work);
355}
356
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
357void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
358{
359	if (!wq)
360		return;
361	destroy_workqueue(wq->normal_wq);
362	trace_btrfs_workqueue_destroy(wq);
 
363	kfree(wq);
364}
365
366void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
367{
368	if (wq)
369		wq->limit_active = limit_active;
 
 
 
370}
371
372void btrfs_flush_workqueue(struct btrfs_workqueue *wq)
373{
374	flush_workqueue(wq->normal_wq);
375}