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
dlm_del_ast(struct dlm_lkb * lkb)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
dlm_add_ast(struct dlm_lkb * lkb,int type,int bastmode)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
process_asts(void)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
no_asts(void)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
dlm_astd(void * data)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
dlm_astd_wake(void)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
dlm_astd_start(void)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
dlm_astd_stop(void)151 void dlm_astd_stop(void)
152 {
153 kthread_stop(astd_task);
154 }
155
dlm_astd_suspend(void)156 void dlm_astd_suspend(void)
157 {
158 mutex_lock(&astd_running);
159 }
160
dlm_astd_resume(void)161 void dlm_astd_resume(void)
162 {
163 mutex_unlock(&astd_running);
164 }
165
166