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Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* General filesystem local caching manager
3 *
4 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define FSCACHE_DEBUG_LEVEL CACHE
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/sched.h>
12#include <linux/completion.h>
13#include <linux/slab.h>
14#include <linux/seq_file.h>
15#define CREATE_TRACE_POINTS
16#include "internal.h"
17
18MODULE_DESCRIPTION("FS Cache Manager");
19MODULE_AUTHOR("Red Hat, Inc.");
20MODULE_LICENSE("GPL");
21
22unsigned fscache_defer_lookup = 1;
23module_param_named(defer_lookup, fscache_defer_lookup, uint,
24 S_IWUSR | S_IRUGO);
25MODULE_PARM_DESC(fscache_defer_lookup,
26 "Defer cookie lookup to background thread");
27
28unsigned fscache_defer_create = 1;
29module_param_named(defer_create, fscache_defer_create, uint,
30 S_IWUSR | S_IRUGO);
31MODULE_PARM_DESC(fscache_defer_create,
32 "Defer cookie creation to background thread");
33
34unsigned fscache_debug;
35module_param_named(debug, fscache_debug, uint,
36 S_IWUSR | S_IRUGO);
37MODULE_PARM_DESC(fscache_debug,
38 "FS-Cache debugging mask");
39
40struct kobject *fscache_root;
41struct workqueue_struct *fscache_object_wq;
42struct workqueue_struct *fscache_op_wq;
43
44DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
45
46/* these values serve as lower bounds, will be adjusted in fscache_init() */
47static unsigned fscache_object_max_active = 4;
48static unsigned fscache_op_max_active = 2;
49
50#ifdef CONFIG_SYSCTL
51static struct ctl_table_header *fscache_sysctl_header;
52
53static int fscache_max_active_sysctl(struct ctl_table *table, int write,
54 void __user *buffer,
55 size_t *lenp, loff_t *ppos)
56{
57 struct workqueue_struct **wqp = table->extra1;
58 unsigned int *datap = table->data;
59 int ret;
60
61 ret = proc_dointvec(table, write, buffer, lenp, ppos);
62 if (ret == 0)
63 workqueue_set_max_active(*wqp, *datap);
64 return ret;
65}
66
67static struct ctl_table fscache_sysctls[] = {
68 {
69 .procname = "object_max_active",
70 .data = &fscache_object_max_active,
71 .maxlen = sizeof(unsigned),
72 .mode = 0644,
73 .proc_handler = fscache_max_active_sysctl,
74 .extra1 = &fscache_object_wq,
75 },
76 {
77 .procname = "operation_max_active",
78 .data = &fscache_op_max_active,
79 .maxlen = sizeof(unsigned),
80 .mode = 0644,
81 .proc_handler = fscache_max_active_sysctl,
82 .extra1 = &fscache_op_wq,
83 },
84 {}
85};
86
87static struct ctl_table fscache_sysctls_root[] = {
88 {
89 .procname = "fscache",
90 .mode = 0555,
91 .child = fscache_sysctls,
92 },
93 {}
94};
95#endif
96
97/*
98 * initialise the fs caching module
99 */
100static int __init fscache_init(void)
101{
102 unsigned int nr_cpus = num_possible_cpus();
103 unsigned int cpu;
104 int ret;
105
106 fscache_object_max_active =
107 clamp_val(nr_cpus,
108 fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
109
110 ret = -ENOMEM;
111 fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
112 fscache_object_max_active);
113 if (!fscache_object_wq)
114 goto error_object_wq;
115
116 fscache_op_max_active =
117 clamp_val(fscache_object_max_active / 2,
118 fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
119
120 ret = -ENOMEM;
121 fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
122 fscache_op_max_active);
123 if (!fscache_op_wq)
124 goto error_op_wq;
125
126 for_each_possible_cpu(cpu)
127 init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
128
129 ret = fscache_proc_init();
130 if (ret < 0)
131 goto error_proc;
132
133#ifdef CONFIG_SYSCTL
134 ret = -ENOMEM;
135 fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
136 if (!fscache_sysctl_header)
137 goto error_sysctl;
138#endif
139
140 fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
141 sizeof(struct fscache_cookie),
142 0, 0, NULL);
143 if (!fscache_cookie_jar) {
144 pr_notice("Failed to allocate a cookie jar\n");
145 ret = -ENOMEM;
146 goto error_cookie_jar;
147 }
148
149 fscache_root = kobject_create_and_add("fscache", kernel_kobj);
150 if (!fscache_root)
151 goto error_kobj;
152
153 pr_notice("Loaded\n");
154 return 0;
155
156error_kobj:
157 kmem_cache_destroy(fscache_cookie_jar);
158error_cookie_jar:
159#ifdef CONFIG_SYSCTL
160 unregister_sysctl_table(fscache_sysctl_header);
161error_sysctl:
162#endif
163 fscache_proc_cleanup();
164error_proc:
165 destroy_workqueue(fscache_op_wq);
166error_op_wq:
167 destroy_workqueue(fscache_object_wq);
168error_object_wq:
169 return ret;
170}
171
172fs_initcall(fscache_init);
173
174/*
175 * clean up on module removal
176 */
177static void __exit fscache_exit(void)
178{
179 _enter("");
180
181 kobject_put(fscache_root);
182 kmem_cache_destroy(fscache_cookie_jar);
183#ifdef CONFIG_SYSCTL
184 unregister_sysctl_table(fscache_sysctl_header);
185#endif
186 fscache_proc_cleanup();
187 destroy_workqueue(fscache_op_wq);
188 destroy_workqueue(fscache_object_wq);
189 pr_notice("Unloaded\n");
190}
191
192module_exit(fscache_exit);