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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}
v6.9.4
  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 <trace/events/btrfs.h>
 13#include "async-thread.h"
 
 14
 15enum {
 16	WORK_DONE_BIT,
 17	WORK_ORDER_DONE_BIT,
 
 18};
 19
 20#define NO_THRESHOLD (-1)
 21#define DFT_THRESHOLD (32)
 22
 23struct btrfs_workqueue {
 24	struct workqueue_struct *normal_wq;
 25
 26	/* File system this workqueue services */
 27	struct btrfs_fs_info *fs_info;
 28
 29	/* List head pointing to ordered work list */
 30	struct list_head ordered_list;
 31
 32	/* Spinlock for ordered_list */
 33	spinlock_t list_lock;
 34
 35	/* Thresholding related variants */
 36	atomic_t pending;
 37
 38	/* Up limit of concurrency workers */
 39	int limit_active;
 40
 41	/* Current number of concurrency workers */
 42	int current_active;
 43
 44	/* Threshold to change current_active */
 45	int thresh;
 46	unsigned int count;
 47	spinlock_t thres_lock;
 48};
 49
 50struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct btrfs_workqueue *wq)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 51{
 52	return wq->fs_info;
 53}
 54
 55struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work)
 
 56{
 57	return work->wq->fs_info;
 58}
 59
 60bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq)
 61{
 62	/*
 63	 * We could compare wq->pending with num_online_cpus()
 64	 * to support "thresh == NO_THRESHOLD" case, but it requires
 65	 * moving up atomic_inc/dec in thresh_queue/exec_hook. Let's
 66	 * postpone it until someone needs the support of that case.
 67	 */
 68	if (wq->thresh == NO_THRESHOLD)
 69		return false;
 70
 71	return atomic_read(&wq->pending) > wq->thresh * 2;
 72}
 73
 74static void btrfs_init_workqueue(struct btrfs_workqueue *wq,
 75				 struct btrfs_fs_info *fs_info)
 76{
 77	wq->fs_info = fs_info;
 78	atomic_set(&wq->pending, 0);
 79	INIT_LIST_HEAD(&wq->ordered_list);
 80	spin_lock_init(&wq->list_lock);
 81	spin_lock_init(&wq->thres_lock);
 82}
 83
 84struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
 85					      const char *name, unsigned int flags,
 86					      int limit_active, int thresh)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 87{
 88	struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
 89
 90	if (!ret)
 91		return NULL;
 92
 93	btrfs_init_workqueue(ret, fs_info);
 94
 95	ret->limit_active = limit_active;
 
 96	if (thresh == 0)
 97		thresh = DFT_THRESHOLD;
 98	/* For low threshold, disabling threshold is a better choice */
 99	if (thresh < DFT_THRESHOLD) {
100		ret->current_active = limit_active;
101		ret->thresh = NO_THRESHOLD;
102	} else {
103		/*
104		 * For threshold-able wq, let its concurrency grow on demand.
105		 * Use minimal max_active at alloc time to reduce resource
106		 * usage.
107		 */
108		ret->current_active = 1;
109		ret->thresh = thresh;
110	}
111
112	ret->normal_wq = alloc_workqueue("btrfs-%s", flags, ret->current_active,
113					 name);
 
 
 
 
114	if (!ret->normal_wq) {
115		kfree(ret);
116		return NULL;
117	}
118
119	trace_btrfs_workqueue_alloc(ret, name);
 
 
 
120	return ret;
121}
122
123struct btrfs_workqueue *btrfs_alloc_ordered_workqueue(
124				struct btrfs_fs_info *fs_info, const char *name,
125				unsigned int flags)
 
 
 
 
 
126{
127	struct btrfs_workqueue *ret;
128
129	ret = kzalloc(sizeof(*ret), GFP_KERNEL);
130	if (!ret)
131		return NULL;
132
133	btrfs_init_workqueue(ret, fs_info);
134
135	/* Ordered workqueues don't allow @max_active adjustments. */
136	ret->limit_active = 1;
137	ret->current_active = 1;
138	ret->thresh = NO_THRESHOLD;
139
140	ret->normal_wq = alloc_ordered_workqueue("btrfs-%s", flags, name);
141	if (!ret->normal_wq) {
142		kfree(ret);
143		return NULL;
144	}
145
146	trace_btrfs_workqueue_alloc(ret, name);
 
 
 
 
 
 
 
 
147	return ret;
148}
149
150/*
151 * Hook for threshold which will be called in btrfs_queue_work.
152 * This hook WILL be called in IRQ handler context,
153 * so workqueue_set_max_active MUST NOT be called in this hook
154 */
155static inline void thresh_queue_hook(struct btrfs_workqueue *wq)
156{
157	if (wq->thresh == NO_THRESHOLD)
158		return;
159	atomic_inc(&wq->pending);
160}
161
162/*
163 * Hook for threshold which will be called before executing the work,
164 * This hook is called in kthread content.
165 * So workqueue_set_max_active is called here.
166 */
167static inline void thresh_exec_hook(struct btrfs_workqueue *wq)
168{
169	int new_current_active;
170	long pending;
171	int need_change = 0;
172
173	if (wq->thresh == NO_THRESHOLD)
174		return;
175
176	atomic_dec(&wq->pending);
177	spin_lock(&wq->thres_lock);
178	/*
179	 * Use wq->count to limit the calling frequency of
180	 * workqueue_set_max_active.
181	 */
182	wq->count++;
183	wq->count %= (wq->thresh / 4);
184	if (!wq->count)
185		goto  out;
186	new_current_active = wq->current_active;
187
188	/*
189	 * pending may be changed later, but it's OK since we really
190	 * don't need it so accurate to calculate new_max_active.
191	 */
192	pending = atomic_read(&wq->pending);
193	if (pending > wq->thresh)
194		new_current_active++;
195	if (pending < wq->thresh / 2)
196		new_current_active--;
197	new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
198	if (new_current_active != wq->current_active)  {
199		need_change = 1;
200		wq->current_active = new_current_active;
201	}
202out:
203	spin_unlock(&wq->thres_lock);
204
205	if (need_change) {
206		workqueue_set_max_active(wq->normal_wq, wq->current_active);
207	}
208}
209
210static void run_ordered_work(struct btrfs_workqueue *wq,
211			     struct btrfs_work *self)
212{
213	struct list_head *list = &wq->ordered_list;
214	struct btrfs_work *work;
215	spinlock_t *lock = &wq->list_lock;
216	unsigned long flags;
217	bool free_self = false;
218
219	while (1) {
 
 
220		spin_lock_irqsave(lock, flags);
221		if (list_empty(list))
222			break;
223		work = list_entry(list->next, struct btrfs_work,
224				  ordered_list);
225		if (!test_bit(WORK_DONE_BIT, &work->flags))
226			break;
227		/*
228		 * Orders all subsequent loads after reading WORK_DONE_BIT,
229		 * paired with the smp_mb__before_atomic in btrfs_work_helper
230		 * this guarantees that the ordered function will see all
231		 * updates from ordinary work function.
232		 */
233		smp_rmb();
234
235		/*
236		 * we are going to call the ordered done function, but
237		 * we leave the work item on the list as a barrier so
238		 * that later work items that are done don't have their
239		 * functions called before this one returns
240		 */
241		if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
242			break;
243		trace_btrfs_ordered_sched(work);
244		spin_unlock_irqrestore(lock, flags);
245		work->ordered_func(work, false);
246
247		/* now take the lock again and drop our item from the list */
248		spin_lock_irqsave(lock, flags);
249		list_del(&work->ordered_list);
250		spin_unlock_irqrestore(lock, flags);
251
252		if (work == self) {
253			/*
254			 * This is the work item that the worker is currently
255			 * executing.
256			 *
257			 * The kernel workqueue code guarantees non-reentrancy
258			 * of work items. I.e., if a work item with the same
259			 * address and work function is queued twice, the second
260			 * execution is blocked until the first one finishes. A
261			 * work item may be freed and recycled with the same
262			 * work function; the workqueue code assumes that the
263			 * original work item cannot depend on the recycled work
264			 * item in that case (see find_worker_executing_work()).
265			 *
266			 * Note that different types of Btrfs work can depend on
267			 * each other, and one type of work on one Btrfs
268			 * filesystem may even depend on the same type of work
269			 * on another Btrfs filesystem via, e.g., a loop device.
270			 * Therefore, we must not allow the current work item to
271			 * be recycled until we are really done, otherwise we
272			 * break the above assumption and can deadlock.
273			 */
274			free_self = true;
275		} else {
276			/*
277			 * We don't want to call the ordered free functions with
278			 * the lock held.
279			 */
280			work->ordered_func(work, true);
281			/* NB: work must not be dereferenced past this point. */
282			trace_btrfs_all_work_done(wq->fs_info, work);
283		}
284	}
285	spin_unlock_irqrestore(lock, flags);
286
287	if (free_self) {
288		self->ordered_func(self, true);
289		/* NB: self must not be dereferenced past this point. */
290		trace_btrfs_all_work_done(wq->fs_info, self);
291	}
292}
293
294static void btrfs_work_helper(struct work_struct *normal_work)
295{
296	struct btrfs_work *work = container_of(normal_work, struct btrfs_work,
297					       normal_work);
298	struct btrfs_workqueue *wq = work->wq;
299	int need_order = 0;
300
301	/*
302	 * We should not touch things inside work in the following cases:
303	 * 1) after work->func() if it has no ordered_func(..., true) to free
304	 *    Since the struct is freed in work->func().
305	 * 2) after setting WORK_DONE_BIT
306	 *    The work may be freed in other threads almost instantly.
307	 * So we save the needed things here.
308	 */
309	if (work->ordered_func)
310		need_order = 1;
 
 
 
311
312	trace_btrfs_work_sched(work);
313	thresh_exec_hook(wq);
314	work->func(work);
315	if (need_order) {
316		/*
317		 * Ensures all memory accesses done in the work function are
318		 * ordered before setting the WORK_DONE_BIT. Ensuring the thread
319		 * which is going to executed the ordered work sees them.
320		 * Pairs with the smp_rmb in run_ordered_work.
321		 */
322		smp_mb__before_atomic();
323		set_bit(WORK_DONE_BIT, &work->flags);
324		run_ordered_work(wq, work);
325	} else {
326		/* NB: work must not be dereferenced past this point. */
327		trace_btrfs_all_work_done(wq->fs_info, work);
328	}
 
 
329}
330
331void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func,
332		     btrfs_ordered_func_t ordered_func)
 
 
333{
334	work->func = func;
335	work->ordered_func = ordered_func;
336	INIT_WORK(&work->normal_work, btrfs_work_helper);
 
337	INIT_LIST_HEAD(&work->ordered_list);
338	work->flags = 0;
339}
340
341void btrfs_queue_work(struct btrfs_workqueue *wq, struct btrfs_work *work)
 
342{
343	unsigned long flags;
344
345	work->wq = wq;
346	thresh_queue_hook(wq);
347	if (work->ordered_func) {
348		spin_lock_irqsave(&wq->list_lock, flags);
349		list_add_tail(&work->ordered_list, &wq->ordered_list);
350		spin_unlock_irqrestore(&wq->list_lock, flags);
351	}
352	trace_btrfs_work_queued(work);
353	queue_work(wq->normal_wq, &work->normal_work);
354}
355
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
356void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
357{
358	if (!wq)
359		return;
360	destroy_workqueue(wq->normal_wq);
361	trace_btrfs_workqueue_destroy(wq);
 
362	kfree(wq);
363}
364
365void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
366{
367	if (wq)
368		wq->limit_active = limit_active;
 
 
 
369}
370
371void btrfs_flush_workqueue(struct btrfs_workqueue *wq)
372{
373	flush_workqueue(wq->normal_wq);
374}