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 18 MODULE_DESCRIPTION("FS Cache Manager"); 19 MODULE_AUTHOR("Red Hat, Inc."); 20 MODULE_LICENSE("GPL"); 21 22 unsigned fscache_defer_lookup = 1; 23 module_param_named(defer_lookup, fscache_defer_lookup, uint, 24 S_IWUSR | S_IRUGO); 25 MODULE_PARM_DESC(fscache_defer_lookup, 26 "Defer cookie lookup to background thread"); 27 28 unsigned fscache_defer_create = 1; 29 module_param_named(defer_create, fscache_defer_create, uint, 30 S_IWUSR | S_IRUGO); 31 MODULE_PARM_DESC(fscache_defer_create, 32 "Defer cookie creation to background thread"); 33 34 unsigned fscache_debug; 35 module_param_named(debug, fscache_debug, uint, 36 S_IWUSR | S_IRUGO); 37 MODULE_PARM_DESC(fscache_debug, 38 "FS-Cache debugging mask"); 39 40 struct kobject *fscache_root; 41 struct workqueue_struct *fscache_object_wq; 42 struct workqueue_struct *fscache_op_wq; 43 44 DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait); 45 46 /* these values serve as lower bounds, will be adjusted in fscache_init() */ 47 static unsigned fscache_object_max_active = 4; 48 static unsigned fscache_op_max_active = 2; 49 50 #ifdef CONFIG_SYSCTL 51 static struct ctl_table_header *fscache_sysctl_header; 52 53 static 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 67 static 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 87 static 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 */ 100 static 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; 155 156 error_kobj: 157 kmem_cache_destroy(fscache_cookie_jar); 158 error_cookie_jar: 159 #ifdef CONFIG_SYSCTL 160 unregister_sysctl_table(fscache_sysctl_header); 161 error_sysctl: 162 #endif 163 fscache_proc_cleanup(); 164 error_proc: 165 destroy_workqueue(fscache_op_wq); 166 error_op_wq: 167 destroy_workqueue(fscache_object_wq); 168 error_object_wq: 169 return ret; 170 } 171 172 fs_initcall(fscache_init); 173 174 /* 175 * clean up on module removal 176 */ 177 static 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 } 191 192 module_exit(fscache_exit); 193