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 *buffer, size_t *lenp, loff_t *ppos) 55 { 56 struct workqueue_struct **wqp = table->extra1; 57 unsigned int *datap = table->data; 58 int ret; 59 60 ret = proc_dointvec(table, write, buffer, lenp, ppos); 61 if (ret == 0) 62 workqueue_set_max_active(*wqp, *datap); 63 return ret; 64 } 65 66 static struct ctl_table fscache_sysctls[] = { 67 { 68 .procname = "object_max_active", 69 .data = &fscache_object_max_active, 70 .maxlen = sizeof(unsigned), 71 .mode = 0644, 72 .proc_handler = fscache_max_active_sysctl, 73 .extra1 = &fscache_object_wq, 74 }, 75 { 76 .procname = "operation_max_active", 77 .data = &fscache_op_max_active, 78 .maxlen = sizeof(unsigned), 79 .mode = 0644, 80 .proc_handler = fscache_max_active_sysctl, 81 .extra1 = &fscache_op_wq, 82 }, 83 {} 84 }; 85 86 static struct ctl_table fscache_sysctls_root[] = { 87 { 88 .procname = "fscache", 89 .mode = 0555, 90 .child = fscache_sysctls, 91 }, 92 {} 93 }; 94 #endif 95 96 /* 97 * initialise the fs caching module 98 */ 99 static int __init fscache_init(void) 100 { 101 unsigned int nr_cpus = num_possible_cpus(); 102 unsigned int cpu; 103 int ret; 104 105 fscache_object_max_active = 106 clamp_val(nr_cpus, 107 fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE); 108 109 ret = -ENOMEM; 110 fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND, 111 fscache_object_max_active); 112 if (!fscache_object_wq) 113 goto error_object_wq; 114 115 fscache_op_max_active = 116 clamp_val(fscache_object_max_active / 2, 117 fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE); 118 119 ret = -ENOMEM; 120 fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND, 121 fscache_op_max_active); 122 if (!fscache_op_wq) 123 goto error_op_wq; 124 125 for_each_possible_cpu(cpu) 126 init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu)); 127 128 ret = fscache_proc_init(); 129 if (ret < 0) 130 goto error_proc; 131 132 #ifdef CONFIG_SYSCTL 133 ret = -ENOMEM; 134 fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root); 135 if (!fscache_sysctl_header) 136 goto error_sysctl; 137 #endif 138 139 fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar", 140 sizeof(struct fscache_cookie), 141 0, 0, NULL); 142 if (!fscache_cookie_jar) { 143 pr_notice("Failed to allocate a cookie jar\n"); 144 ret = -ENOMEM; 145 goto error_cookie_jar; 146 } 147 148 fscache_root = kobject_create_and_add("fscache", kernel_kobj); 149 if (!fscache_root) 150 goto error_kobj; 151 152 pr_notice("Loaded\n"); 153 return 0; 154 155 error_kobj: 156 kmem_cache_destroy(fscache_cookie_jar); 157 error_cookie_jar: 158 #ifdef CONFIG_SYSCTL 159 unregister_sysctl_table(fscache_sysctl_header); 160 error_sysctl: 161 #endif 162 fscache_proc_cleanup(); 163 error_proc: 164 destroy_workqueue(fscache_op_wq); 165 error_op_wq: 166 destroy_workqueue(fscache_object_wq); 167 error_object_wq: 168 return ret; 169 } 170 171 fs_initcall(fscache_init); 172 173 /* 174 * clean up on module removal 175 */ 176 static void __exit fscache_exit(void) 177 { 178 _enter(""); 179 180 kobject_put(fscache_root); 181 kmem_cache_destroy(fscache_cookie_jar); 182 #ifdef CONFIG_SYSCTL 183 unregister_sysctl_table(fscache_sysctl_header); 184 #endif 185 fscache_proc_cleanup(); 186 destroy_workqueue(fscache_op_wq); 187 destroy_workqueue(fscache_object_wq); 188 pr_notice("Unloaded\n"); 189 } 190 191 module_exit(fscache_exit); 192