Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * Sleepable Read-Copy Update mechanism for mutual exclusion,
3 * classic v4.11 variant.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, you can access it online at
17 * http://www.gnu.org/licenses/gpl-2.0.html.
18 *
19 * Copyright (C) IBM Corporation, 2017
20 *
21 * Author: Paul McKenney <paulmck@us.ibm.com>
22 */
23
24#ifndef _LINUX_SRCU_CLASSIC_H
25#define _LINUX_SRCU_CLASSIC_H
26
27struct srcu_array {
28 unsigned long lock_count[2];
29 unsigned long unlock_count[2];
30};
31
32struct rcu_batch {
33 struct rcu_head *head, **tail;
34};
35
36#define RCU_BATCH_INIT(name) { NULL, &(name.head) }
37
38struct srcu_struct {
39 unsigned long completed;
40 struct srcu_array __percpu *per_cpu_ref;
41 spinlock_t queue_lock; /* protect ->batch_queue, ->running */
42 bool running;
43 /* callbacks just queued */
44 struct rcu_batch batch_queue;
45 /* callbacks try to do the first check_zero */
46 struct rcu_batch batch_check0;
47 /* callbacks done with the first check_zero and the flip */
48 struct rcu_batch batch_check1;
49 struct rcu_batch batch_done;
50 struct delayed_work work;
51#ifdef CONFIG_DEBUG_LOCK_ALLOC
52 struct lockdep_map dep_map;
53#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
54};
55
56void process_srcu(struct work_struct *work);
57
58#define __SRCU_STRUCT_INIT(name) \
59 { \
60 .completed = -300, \
61 .per_cpu_ref = &name##_srcu_array, \
62 .queue_lock = __SPIN_LOCK_UNLOCKED(name.queue_lock), \
63 .running = false, \
64 .batch_queue = RCU_BATCH_INIT(name.batch_queue), \
65 .batch_check0 = RCU_BATCH_INIT(name.batch_check0), \
66 .batch_check1 = RCU_BATCH_INIT(name.batch_check1), \
67 .batch_done = RCU_BATCH_INIT(name.batch_done), \
68 .work = __DELAYED_WORK_INITIALIZER(name.work, process_srcu, 0),\
69 __SRCU_DEP_MAP_INIT(name) \
70 }
71
72/*
73 * Define and initialize a srcu struct at build time.
74 * Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it.
75 *
76 * Note that although DEFINE_STATIC_SRCU() hides the name from other
77 * files, the per-CPU variable rules nevertheless require that the
78 * chosen name be globally unique. These rules also prohibit use of
79 * DEFINE_STATIC_SRCU() within a function. If these rules are too
80 * restrictive, declare the srcu_struct manually. For example, in
81 * each file:
82 *
83 * static struct srcu_struct my_srcu;
84 *
85 * Then, before the first use of each my_srcu, manually initialize it:
86 *
87 * init_srcu_struct(&my_srcu);
88 *
89 * See include/linux/percpu-defs.h for the rules on per-CPU variables.
90 */
91#define __DEFINE_SRCU(name, is_static) \
92 static DEFINE_PER_CPU(struct srcu_array, name##_srcu_array);\
93 is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name)
94#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
95#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)
96
97void synchronize_srcu_expedited(struct srcu_struct *sp);
98void srcu_barrier(struct srcu_struct *sp);
99unsigned long srcu_batches_completed(struct srcu_struct *sp);
100
101static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
102 struct srcu_struct *sp, int *flags,
103 unsigned long *gpnum,
104 unsigned long *completed)
105{
106 if (test_type != SRCU_FLAVOR)
107 return;
108 *flags = 0;
109 *completed = sp->completed;
110 *gpnum = *completed;
111 if (sp->batch_queue.head || sp->batch_check0.head || sp->batch_check0.head)
112 (*gpnum)++;
113}
114
115#endif