1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/*
* Asynchronous refcounty things
*
* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
* Copyright 2012 Google, Inc.
*/
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/sched/debug.h>
#include "closure.h"
static inline void closure_put_after_sub(struct closure *cl, int flags)
{
int r = flags & CLOSURE_REMAINING_MASK;
BUG_ON(flags & CLOSURE_GUARD_MASK);
BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
if (!r) {
if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
atomic_set(&cl->remaining,
CLOSURE_REMAINING_INITIALIZER);
closure_queue(cl);
} else {
struct closure *parent = cl->parent;
closure_fn *destructor = cl->fn;
closure_debug_destroy(cl);
if (destructor)
destructor(cl);
if (parent)
closure_put(parent);
}
}
}
/* For clearing flags with the same atomic op as a put */
void closure_sub(struct closure *cl, int v)
{
closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining));
}
EXPORT_SYMBOL(closure_sub);
/*
* closure_put - decrement a closure's refcount
*/
void closure_put(struct closure *cl)
{
closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
}
EXPORT_SYMBOL(closure_put);
/*
* closure_wake_up - wake up all closures on a wait list, without memory barrier
*/
void __closure_wake_up(struct closure_waitlist *wait_list)
{
struct llist_node *list;
struct closure *cl, *t;
struct llist_node *reverse = NULL;
list = llist_del_all(&wait_list->list);
/* We first reverse the list to preserve FIFO ordering and fairness */
reverse = llist_reverse_order(list);
/* Then do the wakeups */
llist_for_each_entry_safe(cl, t, reverse, list) {
closure_set_waiting(cl, 0);
closure_sub(cl, CLOSURE_WAITING + 1);
}
}
EXPORT_SYMBOL(__closure_wake_up);
/**
* closure_wait - add a closure to a waitlist
* @waitlist: will own a ref on @cl, which will be released when
* closure_wake_up() is called on @waitlist.
* @cl: closure pointer.
*
*/
bool closure_wait(struct closure_waitlist *waitlist, struct closure *cl)
{
if (atomic_read(&cl->remaining) & CLOSURE_WAITING)
return false;
closure_set_waiting(cl, _RET_IP_);
atomic_add(CLOSURE_WAITING + 1, &cl->remaining);
llist_add(&cl->list, &waitlist->list);
return true;
}
EXPORT_SYMBOL(closure_wait);
struct closure_syncer {
struct task_struct *task;
int done;
};
static void closure_sync_fn(struct closure *cl)
{
cl->s->done = 1;
wake_up_process(cl->s->task);
}
void __sched __closure_sync(struct closure *cl)
{
struct closure_syncer s = { .task = current };
cl->s = &s;
continue_at(cl, closure_sync_fn, NULL);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (s.done)
break;
schedule();
}
__set_current_state(TASK_RUNNING);
}
EXPORT_SYMBOL(__closure_sync);
#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
static LIST_HEAD(closure_list);
static DEFINE_SPINLOCK(closure_list_lock);
void closure_debug_create(struct closure *cl)
{
unsigned long flags;
BUG_ON(cl->magic == CLOSURE_MAGIC_ALIVE);
cl->magic = CLOSURE_MAGIC_ALIVE;
spin_lock_irqsave(&closure_list_lock, flags);
list_add(&cl->all, &closure_list);
spin_unlock_irqrestore(&closure_list_lock, flags);
}
EXPORT_SYMBOL(closure_debug_create);
void closure_debug_destroy(struct closure *cl)
{
unsigned long flags;
BUG_ON(cl->magic != CLOSURE_MAGIC_ALIVE);
cl->magic = CLOSURE_MAGIC_DEAD;
spin_lock_irqsave(&closure_list_lock, flags);
list_del(&cl->all);
spin_unlock_irqrestore(&closure_list_lock, flags);
}
EXPORT_SYMBOL(closure_debug_destroy);
static struct dentry *closure_debug;
static int debug_seq_show(struct seq_file *f, void *data)
{
struct closure *cl;
spin_lock_irq(&closure_list_lock);
list_for_each_entry(cl, &closure_list, all) {
int r = atomic_read(&cl->remaining);
seq_printf(f, "%p: %pF -> %pf p %p r %i ",
cl, (void *) cl->ip, cl->fn, cl->parent,
r & CLOSURE_REMAINING_MASK);
seq_printf(f, "%s%s\n",
test_bit(WORK_STRUCT_PENDING_BIT,
work_data_bits(&cl->work)) ? "Q" : "",
r & CLOSURE_RUNNING ? "R" : "");
if (r & CLOSURE_WAITING)
seq_printf(f, " W %pF\n",
(void *) cl->waiting_on);
seq_printf(f, "\n");
}
spin_unlock_irq(&closure_list_lock);
return 0;
}
static int debug_seq_open(struct inode *inode, struct file *file)
{
return single_open(file, debug_seq_show, NULL);
}
static const struct file_operations debug_ops = {
.owner = THIS_MODULE,
.open = debug_seq_open,
.read = seq_read,
.release = single_release
};
void __init closure_debug_init(void)
{
if (!IS_ERR_OR_NULL(bcache_debug))
/*
* it is unnecessary to check return value of
* debugfs_create_file(), we should not care
* about this.
*/
closure_debug = debugfs_create_file(
"closures", 0400, bcache_debug, NULL, &debug_ops);
}
#endif
MODULE_AUTHOR("Kent Overstreet <koverstreet@google.com>");
MODULE_LICENSE("GPL");
|
