/* General filesystem local caching manager * * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #define FSCACHE_DEBUG_LEVEL CACHE #include <linux/module.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/completion.h> #include <linux/slab.h> #include <linux/seq_file.h> #include "internal.h" MODULE_DESCRIPTION("FS Cache Manager"); MODULE_AUTHOR("Red Hat, Inc."); MODULE_LICENSE("GPL"); unsigned fscache_defer_lookup = 1; module_param_named(defer_lookup, fscache_defer_lookup, uint, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(fscache_defer_lookup, "Defer cookie lookup to background thread"); unsigned fscache_defer_create = 1; module_param_named(defer_create, fscache_defer_create, uint, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(fscache_defer_create, "Defer cookie creation to background thread"); unsigned fscache_debug; module_param_named(debug, fscache_debug, uint, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(fscache_debug, "FS-Cache debugging mask"); struct kobject *fscache_root; struct workqueue_struct *fscache_object_wq; struct workqueue_struct *fscache_op_wq; DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait); /* these values serve as lower bounds, will be adjusted in fscache_init() */ static unsigned fscache_object_max_active = 4; static unsigned fscache_op_max_active = 2; #ifdef CONFIG_SYSCTL static struct ctl_table_header *fscache_sysctl_header; static int fscache_max_active_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { struct workqueue_struct **wqp = table->extra1; unsigned int *datap = table->data; int ret; ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret == 0) workqueue_set_max_active(*wqp, *datap); return ret; } static struct ctl_table fscache_sysctls[] = { { .procname = "object_max_active", .data = &fscache_object_max_active, .maxlen = sizeof(unsigned), .mode = 0644, .proc_handler = fscache_max_active_sysctl, .extra1 = &fscache_object_wq, }, { .procname = "operation_max_active", .data = &fscache_op_max_active, .maxlen = sizeof(unsigned), .mode = 0644, .proc_handler = fscache_max_active_sysctl, .extra1 = &fscache_op_wq, }, {} }; static struct ctl_table fscache_sysctls_root[] = { { .procname = "fscache", .mode = 0555, .child = fscache_sysctls, }, {} }; #endif /* * initialise the fs caching module */ static int __init fscache_init(void) { unsigned int nr_cpus = num_possible_cpus(); unsigned int cpu; int ret; fscache_object_max_active = clamp_val(nr_cpus, fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE); ret = -ENOMEM; fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND, fscache_object_max_active); if (!fscache_object_wq) goto error_object_wq; fscache_op_max_active = clamp_val(fscache_object_max_active / 2, fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE); ret = -ENOMEM; fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND, fscache_op_max_active); if (!fscache_op_wq) goto error_op_wq; for_each_possible_cpu(cpu) init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu)); ret = fscache_proc_init(); if (ret < 0) goto error_proc; #ifdef CONFIG_SYSCTL ret = -ENOMEM; fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root); if (!fscache_sysctl_header) goto error_sysctl; #endif fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar", sizeof(struct fscache_cookie), 0, 0, fscache_cookie_init_once); if (!fscache_cookie_jar) { pr_notice("Failed to allocate a cookie jar\n"); ret = -ENOMEM; goto error_cookie_jar; } fscache_root = kobject_create_and_add("fscache", kernel_kobj); if (!fscache_root) goto error_kobj; pr_notice("Loaded\n"); return 0; error_kobj: kmem_cache_destroy(fscache_cookie_jar); error_cookie_jar: #ifdef CONFIG_SYSCTL unregister_sysctl_table(fscache_sysctl_header); error_sysctl: #endif fscache_proc_cleanup(); error_proc: destroy_workqueue(fscache_op_wq); error_op_wq: destroy_workqueue(fscache_object_wq); error_object_wq: return ret; } fs_initcall(fscache_init); /* * clean up on module removal */ static void __exit fscache_exit(void) { _enter(""); kobject_put(fscache_root); kmem_cache_destroy(fscache_cookie_jar); #ifdef CONFIG_SYSCTL unregister_sysctl_table(fscache_sysctl_header); #endif fscache_proc_cleanup(); destroy_workqueue(fscache_op_wq); destroy_workqueue(fscache_object_wq); pr_notice("Unloaded\n"); } module_exit(fscache_exit); /* * wait_on_atomic_t() sleep function for uninterruptible waiting */ int fscache_wait_atomic_t(atomic_t *p) { schedule(); return 0; }