Root/
1 | /****************************************************************************** |
2 | ******************************************************************************* |
3 | ** |
4 | ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. |
5 | ** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
6 | ** |
7 | ** This copyrighted material is made available to anyone wishing to use, |
8 | ** modify, copy, or redistribute it subject to the terms and conditions |
9 | ** of the GNU General Public License v.2. |
10 | ** |
11 | ******************************************************************************* |
12 | ******************************************************************************/ |
13 | |
14 | #include "dlm_internal.h" |
15 | #include "lock.h" |
16 | #include "user.h" |
17 | #include "ast.h" |
18 | |
19 | #define WAKE_ASTS 0 |
20 | |
21 | static struct list_head ast_queue; |
22 | static spinlock_t ast_queue_lock; |
23 | static struct task_struct * astd_task; |
24 | static unsigned long astd_wakeflags; |
25 | static struct mutex astd_running; |
26 | |
27 | |
28 | void dlm_del_ast(struct dlm_lkb *lkb) |
29 | { |
30 | spin_lock(&ast_queue_lock); |
31 | if (lkb->lkb_ast_type & (AST_COMP | AST_BAST)) |
32 | list_del(&lkb->lkb_astqueue); |
33 | spin_unlock(&ast_queue_lock); |
34 | } |
35 | |
36 | void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode) |
37 | { |
38 | if (lkb->lkb_flags & DLM_IFL_USER) { |
39 | dlm_user_add_ast(lkb, type, bastmode); |
40 | return; |
41 | } |
42 | |
43 | spin_lock(&ast_queue_lock); |
44 | if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) { |
45 | kref_get(&lkb->lkb_ref); |
46 | list_add_tail(&lkb->lkb_astqueue, &ast_queue); |
47 | } |
48 | lkb->lkb_ast_type |= type; |
49 | if (bastmode) |
50 | lkb->lkb_bastmode = bastmode; |
51 | spin_unlock(&ast_queue_lock); |
52 | |
53 | set_bit(WAKE_ASTS, &astd_wakeflags); |
54 | wake_up_process(astd_task); |
55 | } |
56 | |
57 | static void process_asts(void) |
58 | { |
59 | struct dlm_ls *ls = NULL; |
60 | struct dlm_rsb *r = NULL; |
61 | struct dlm_lkb *lkb; |
62 | void (*cast) (void *astparam); |
63 | void (*bast) (void *astparam, int mode); |
64 | int type = 0, bastmode; |
65 | |
66 | repeat: |
67 | spin_lock(&ast_queue_lock); |
68 | list_for_each_entry(lkb, &ast_queue, lkb_astqueue) { |
69 | r = lkb->lkb_resource; |
70 | ls = r->res_ls; |
71 | |
72 | if (dlm_locking_stopped(ls)) |
73 | continue; |
74 | |
75 | list_del(&lkb->lkb_astqueue); |
76 | type = lkb->lkb_ast_type; |
77 | lkb->lkb_ast_type = 0; |
78 | bastmode = lkb->lkb_bastmode; |
79 | |
80 | spin_unlock(&ast_queue_lock); |
81 | cast = lkb->lkb_astfn; |
82 | bast = lkb->lkb_bastfn; |
83 | |
84 | if ((type & AST_COMP) && cast) |
85 | cast(lkb->lkb_astparam); |
86 | |
87 | if ((type & AST_BAST) && bast) |
88 | bast(lkb->lkb_astparam, bastmode); |
89 | |
90 | /* this removes the reference added by dlm_add_ast |
91 | and may result in the lkb being freed */ |
92 | dlm_put_lkb(lkb); |
93 | |
94 | cond_resched(); |
95 | goto repeat; |
96 | } |
97 | spin_unlock(&ast_queue_lock); |
98 | } |
99 | |
100 | static inline int no_asts(void) |
101 | { |
102 | int ret; |
103 | |
104 | spin_lock(&ast_queue_lock); |
105 | ret = list_empty(&ast_queue); |
106 | spin_unlock(&ast_queue_lock); |
107 | return ret; |
108 | } |
109 | |
110 | static int dlm_astd(void *data) |
111 | { |
112 | while (!kthread_should_stop()) { |
113 | set_current_state(TASK_INTERRUPTIBLE); |
114 | if (!test_bit(WAKE_ASTS, &astd_wakeflags)) |
115 | schedule(); |
116 | set_current_state(TASK_RUNNING); |
117 | |
118 | mutex_lock(&astd_running); |
119 | if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags)) |
120 | process_asts(); |
121 | mutex_unlock(&astd_running); |
122 | } |
123 | return 0; |
124 | } |
125 | |
126 | void dlm_astd_wake(void) |
127 | { |
128 | if (!no_asts()) { |
129 | set_bit(WAKE_ASTS, &astd_wakeflags); |
130 | wake_up_process(astd_task); |
131 | } |
132 | } |
133 | |
134 | int dlm_astd_start(void) |
135 | { |
136 | struct task_struct *p; |
137 | int error = 0; |
138 | |
139 | INIT_LIST_HEAD(&ast_queue); |
140 | spin_lock_init(&ast_queue_lock); |
141 | mutex_init(&astd_running); |
142 | |
143 | p = kthread_run(dlm_astd, NULL, "dlm_astd"); |
144 | if (IS_ERR(p)) |
145 | error = PTR_ERR(p); |
146 | else |
147 | astd_task = p; |
148 | return error; |
149 | } |
150 | |
151 | void dlm_astd_stop(void) |
152 | { |
153 | kthread_stop(astd_task); |
154 | } |
155 | |
156 | void dlm_astd_suspend(void) |
157 | { |
158 | mutex_lock(&astd_running); |
159 | } |
160 | |
161 | void dlm_astd_resume(void) |
162 | { |
163 | mutex_unlock(&astd_running); |
164 | } |
165 | |
166 |
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Tags:
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od-2011-09-18
v2.6.34-rc5
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