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
|
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "lock.h"
#include "user.h"
#include "ast.h"
#define WAKE_ASTS 0
static struct list_head ast_queue;
static spinlock_t ast_queue_lock;
static struct task_struct * astd_task;
static unsigned long astd_wakeflags;
static struct mutex astd_running;
void dlm_del_ast(struct dlm_lkb *lkb)
{
spin_lock(&ast_queue_lock);
if (lkb->lkb_ast_type & (AST_COMP | AST_BAST))
list_del(&lkb->lkb_astqueue);
spin_unlock(&ast_queue_lock);
}
void dlm_add_ast(struct dlm_lkb *lkb, int type, int mode)
{
if (lkb->lkb_flags & DLM_IFL_USER) {
dlm_user_add_ast(lkb, type, mode);
return;
}
spin_lock(&ast_queue_lock);
if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
kref_get(&lkb->lkb_ref);
list_add_tail(&lkb->lkb_astqueue, &ast_queue);
lkb->lkb_ast_first = type;
}
/* sanity check, this should not happen */
if ((type == AST_COMP) && (lkb->lkb_ast_type & AST_COMP))
log_print("repeat cast %d castmode %d lock %x %s",
mode, lkb->lkb_castmode,
lkb->lkb_id, lkb->lkb_resource->res_name);
lkb->lkb_ast_type |= type;
if (type == AST_BAST)
lkb->lkb_bastmode = mode;
else
lkb->lkb_castmode = mode;
spin_unlock(&ast_queue_lock);
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
static void process_asts(void)
{
struct dlm_ls *ls = NULL;
struct dlm_rsb *r = NULL;
struct dlm_lkb *lkb;
void (*castfn) (void *astparam);
void (*bastfn) (void *astparam, int mode);
int type, first, bastmode, castmode, do_bast, do_cast, last_castmode;
repeat:
spin_lock(&ast_queue_lock);
list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
r = lkb->lkb_resource;
ls = r->res_ls;
if (dlm_locking_stopped(ls))
continue;
list_del(&lkb->lkb_astqueue);
type = lkb->lkb_ast_type;
lkb->lkb_ast_type = 0;
first = lkb->lkb_ast_first;
lkb->lkb_ast_first = 0;
bastmode = lkb->lkb_bastmode;
castmode = lkb->lkb_castmode;
castfn = lkb->lkb_astfn;
bastfn = lkb->lkb_bastfn;
spin_unlock(&ast_queue_lock);
do_cast = (type & AST_COMP) && castfn;
do_bast = (type & AST_BAST) && bastfn;
/* Skip a bast if its blocking mode is compatible with the
granted mode of the preceding cast. */
if (do_bast) {
if (first == AST_COMP)
last_castmode = castmode;
else
last_castmode = lkb->lkb_castmode_done;
if (dlm_modes_compat(bastmode, last_castmode))
do_bast = 0;
}
if (first == AST_COMP) {
if (do_cast)
castfn(lkb->lkb_astparam);
if (do_bast)
bastfn(lkb->lkb_astparam, bastmode);
} else if (first == AST_BAST) {
if (do_bast)
bastfn(lkb->lkb_astparam, bastmode);
if (do_cast)
castfn(lkb->lkb_astparam);
} else {
log_error(ls, "bad ast_first %d ast_type %d",
first, type);
}
if (do_cast)
lkb->lkb_castmode_done = castmode;
if (do_bast)
lkb->lkb_bastmode_done = bastmode;
/* this removes the reference added by dlm_add_ast
and may result in the lkb being freed */
dlm_put_lkb(lkb);
cond_resched();
goto repeat;
}
spin_unlock(&ast_queue_lock);
}
static inline int no_asts(void)
{
int ret;
spin_lock(&ast_queue_lock);
ret = list_empty(&ast_queue);
spin_unlock(&ast_queue_lock);
return ret;
}
static int dlm_astd(void *data)
{
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!test_bit(WAKE_ASTS, &astd_wakeflags))
schedule();
set_current_state(TASK_RUNNING);
mutex_lock(&astd_running);
if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
process_asts();
mutex_unlock(&astd_running);
}
return 0;
}
void dlm_astd_wake(void)
{
if (!no_asts()) {
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
}
int dlm_astd_start(void)
{
struct task_struct *p;
int error = 0;
INIT_LIST_HEAD(&ast_queue);
spin_lock_init(&ast_queue_lock);
mutex_init(&astd_running);
p = kthread_run(dlm_astd, NULL, "dlm_astd");
if (IS_ERR(p))
error = PTR_ERR(p);
else
astd_task = p;
return error;
}
void dlm_astd_stop(void)
{
kthread_stop(astd_task);
}
void dlm_astd_suspend(void)
{
mutex_lock(&astd_running);
}
void dlm_astd_resume(void)
{
mutex_unlock(&astd_running);
}
|
