tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/******************************************************************************
2*******************************************************************************
3**
4** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5** Copyright (C) 2004-2005 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
21static struct list_head ast_queue;
22static spinlock_t ast_queue_lock;
23static struct task_struct * astd_task;
24static unsigned long astd_wakeflags;
25static struct mutex astd_running;
26
27
28void 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
36void dlm_add_ast(struct dlm_lkb *lkb, int type)
37{
38 if (lkb->lkb_flags & DLM_IFL_USER) {
39 dlm_user_add_ast(lkb, type);
40 return;
41 }
42 DLM_ASSERT(lkb->lkb_astaddr != DLM_FAKE_USER_AST, dlm_print_lkb(lkb););
43
44 spin_lock(&ast_queue_lock);
45 if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
46 kref_get(&lkb->lkb_ref);
47 list_add_tail(&lkb->lkb_astqueue, &ast_queue);
48 }
49 lkb->lkb_ast_type |= type;
50 spin_unlock(&ast_queue_lock);
51
52 set_bit(WAKE_ASTS, &astd_wakeflags);
53 wake_up_process(astd_task);
54}
55
56static void process_asts(void)
57{
58 struct dlm_ls *ls = NULL;
59 struct dlm_rsb *r = NULL;
60 struct dlm_lkb *lkb;
61 void (*cast) (long param);
62 void (*bast) (long param, int mode);
63 int type = 0, found, bmode;
64
65 for (;;) {
66 found = 0;
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 found = 1;
79 break;
80 }
81 spin_unlock(&ast_queue_lock);
82
83 if (!found)
84 break;
85
86 cast = lkb->lkb_astaddr;
87 bast = lkb->lkb_bastaddr;
88 bmode = lkb->lkb_bastmode;
89
90 if ((type & AST_COMP) && cast)
91 cast(lkb->lkb_astparam);
92
93 /* FIXME: Is it safe to look at lkb_grmode here
94 without doing a lock_rsb() ?
95 Look at other checks in v1 to avoid basts. */
96
97 if ((type & AST_BAST) && bast)
98 if (!dlm_modes_compat(lkb->lkb_grmode, bmode))
99 bast(lkb->lkb_astparam, bmode);
100
101 /* this removes the reference added by dlm_add_ast
102 and may result in the lkb being freed */
103 dlm_put_lkb(lkb);
104
105 schedule();
106 }
107}
108
109static inline int no_asts(void)
110{
111 int ret;
112
113 spin_lock(&ast_queue_lock);
114 ret = list_empty(&ast_queue);
115 spin_unlock(&ast_queue_lock);
116 return ret;
117}
118
119static int dlm_astd(void *data)
120{
121 while (!kthread_should_stop()) {
122 set_current_state(TASK_INTERRUPTIBLE);
123 if (!test_bit(WAKE_ASTS, &astd_wakeflags))
124 schedule();
125 set_current_state(TASK_RUNNING);
126
127 mutex_lock(&astd_running);
128 if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
129 process_asts();
130 mutex_unlock(&astd_running);
131 }
132 return 0;
133}
134
135void dlm_astd_wake(void)
136{
137 if (!no_asts()) {
138 set_bit(WAKE_ASTS, &astd_wakeflags);
139 wake_up_process(astd_task);
140 }
141}
142
143int dlm_astd_start(void)
144{
145 struct task_struct *p;
146 int error = 0;
147
148 INIT_LIST_HEAD(&ast_queue);
149 spin_lock_init(&ast_queue_lock);
150 mutex_init(&astd_running);
151
152 p = kthread_run(dlm_astd, NULL, "dlm_astd");
153 if (IS_ERR(p))
154 error = PTR_ERR(p);
155 else
156 astd_task = p;
157 return error;
158}
159
160void dlm_astd_stop(void)
161{
162 kthread_stop(astd_task);
163}
164
165void dlm_astd_suspend(void)
166{
167 mutex_lock(&astd_running);
168}
169
170void dlm_astd_resume(void)
171{
172 mutex_unlock(&astd_running);
173}
174