1 /*-
2  * Copyright (c) 2010 Isilon Systems, Inc.
3  * Copyright (c) 2010 iX Systems, Inc.
4  * Copyright (c) 2010 Panasas, Inc.
5  * Copyright (c) 2013-2015 Mellanox Technologies, Ltd.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice unmodified, this list of conditions, and the following
13  *    disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 #ifndef	_LINUX_WORKQUEUE_H_
30 #define	_LINUX_WORKQUEUE_H_
31 
32 #include <linux/types.h>
33 #include <linux/kernel.h>
34 #include <linux/timer.h>
35 #include <linux/slab.h>
36 
37 #include <asm/atomic.h>
38 
39 #include <sys/taskqueue.h>
40 
41 struct workqueue_struct {
42 	struct taskqueue	*taskqueue;
43 	atomic_t		draining;
44 };
45 
46 struct work_struct {
47 	struct	task 		work_task;
48 	struct	taskqueue	*taskqueue;
49 	void			(*fn)(struct work_struct *);
50 };
51 
52 typedef __typeof(((struct work_struct *)0)->fn) work_func_t;
53 
54 struct delayed_work {
55 	struct work_struct	work;
56 	struct callout		timer;
57 };
58 
59 extern void linux_work_fn(void *, int);
60 extern void linux_flush_fn(void *, int);
61 extern void linux_delayed_work_fn(void *);
62 extern struct workqueue_struct *linux_create_workqueue_common(const char *, int);
63 extern void destroy_workqueue(struct workqueue_struct *);
64 
65 static inline struct delayed_work *
to_delayed_work(struct work_struct * work)66 to_delayed_work(struct work_struct *work)
67 {
68 
69  	return container_of(work, struct delayed_work, work);
70 }
71 
72 #define	INIT_WORK(work, func) 	 					\
73 do {									\
74 	(work)->fn = (func);						\
75 	(work)->taskqueue = NULL;					\
76 	TASK_INIT(&(work)->work_task, 0, linux_work_fn, (work));		\
77 } while (0)
78 
79 #define	INIT_DELAYED_WORK(_work, func)					\
80 do {									\
81 	INIT_WORK(&(_work)->work, func);				\
82 	callout_init(&(_work)->timer, 1);				\
83 } while (0)
84 
85 #define	INIT_DEFERRABLE_WORK(...) INIT_DELAYED_WORK(__VA_ARGS__)
86 
87 #define	schedule_work(work)						\
88 do {									\
89 	(work)->taskqueue = taskqueue_thread;				\
90 	taskqueue_enqueue(taskqueue_thread, &(work)->work_task);	\
91 } while (0)
92 
93 #define	flush_scheduled_work()	flush_taskqueue(taskqueue_thread)
94 
95 static inline int
queue_work(struct workqueue_struct * wq,struct work_struct * work)96 queue_work(struct workqueue_struct *wq, struct work_struct *work)
97 {
98 	work->taskqueue = wq->taskqueue;
99 	/* Check for draining */
100 	if (atomic_read(&wq->draining) != 0)
101 		return (!work->work_task.ta_pending);
102 	/* Return opposite value to align with Linux logic */
103 	return (!taskqueue_enqueue(wq->taskqueue, &work->work_task));
104 }
105 
106 static inline int
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * work,unsigned long delay)107 queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *work,
108     unsigned long delay)
109 {
110 	int pending;
111 
112 	work->work.taskqueue = wq->taskqueue;
113 	if (atomic_read(&wq->draining) != 0) {
114 	  	pending = work->work.work_task.ta_pending;
115 	} else if (delay != 0) {
116 		pending = work->work.work_task.ta_pending;
117 		callout_reset(&work->timer, delay, linux_delayed_work_fn, work);
118 	} else {
119 		callout_stop(&work->timer);
120 		pending = taskqueue_enqueue(work->work.taskqueue,
121 		    &work->work.work_task);
122 	}
123 	return (!pending);
124 }
125 
126 static inline bool
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)127 schedule_delayed_work(struct delayed_work *dwork,
128     unsigned long delay)
129 {
130 	struct workqueue_struct wq;
131 
132 	wq.taskqueue = taskqueue_thread;
133 	atomic_set(&wq.draining, 0);
134 	return (queue_delayed_work(&wq, dwork, delay));
135 }
136 
137 #define	create_singlethread_workqueue(name)				\
138 	linux_create_workqueue_common(name, 1)
139 
140 #define	create_workqueue(name)						\
141 	linux_create_workqueue_common(name, MAXCPU)
142 
143 #define	alloc_ordered_workqueue(name, flags)				\
144 	linux_create_workqueue_common(name, 1)
145 
146 #define	alloc_workqueue(name, flags, max_active)			\
147 	linux_create_workqueue_common(name, max_active)
148 
149 #define	flush_workqueue(wq)	flush_taskqueue((wq)->taskqueue)
150 
151 static inline void
flush_taskqueue(struct taskqueue * tq)152 flush_taskqueue(struct taskqueue *tq)
153 {
154 	struct task flushtask;
155 
156 	PHOLD(curproc);
157 	TASK_INIT(&flushtask, 0, linux_flush_fn, NULL);
158 	taskqueue_enqueue(tq, &flushtask);
159 	taskqueue_drain(tq, &flushtask);
160 	PRELE(curproc);
161 }
162 
163 static inline void
drain_workqueue(struct workqueue_struct * wq)164 drain_workqueue(struct workqueue_struct *wq)
165 {
166 	atomic_inc(&wq->draining);
167 	flush_taskqueue(wq->taskqueue);
168 	atomic_dec(&wq->draining);
169 }
170 
171 static inline int
cancel_work_sync(struct work_struct * work)172 cancel_work_sync(struct work_struct *work)
173 {
174 	if (work->taskqueue &&
175 	    taskqueue_cancel(work->taskqueue, &work->work_task, NULL))
176 		taskqueue_drain(work->taskqueue, &work->work_task);
177 	return 0;
178 }
179 
180 /*
181  * This may leave work running on another CPU as it does on Linux.
182  */
183 static inline int
cancel_delayed_work(struct delayed_work * work)184 cancel_delayed_work(struct delayed_work *work)
185 {
186 
187 	callout_stop(&work->timer);
188 	if (work->work.taskqueue)
189 		return (taskqueue_cancel(work->work.taskqueue,
190 		    &work->work.work_task, NULL) == 0);
191 	return 0;
192 }
193 
194 static inline int
cancel_delayed_work_sync(struct delayed_work * work)195 cancel_delayed_work_sync(struct delayed_work *work)
196 {
197 
198         callout_drain(&work->timer);
199         if (work->work.taskqueue &&
200             taskqueue_cancel(work->work.taskqueue, &work->work.work_task, NULL))
201                 taskqueue_drain(work->work.taskqueue, &work->work.work_task);
202         return 0;
203 }
204 
205 static inline bool
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)206 mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork,
207     unsigned long delay)
208 {
209 	cancel_delayed_work(dwork);
210 	queue_delayed_work(wq, dwork, delay);
211 	return false;
212 }
213 
214 #endif	/* _LINUX_WORKQUEUE_H_ */
215