diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/obdclass/lustre_handles.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/obdclass/lustre_handles.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/obdclass/lustre_handles.c b/drivers/staging/lustre/lustre/obdclass/lustre_handles.c new file mode 100644 index 000000000000..69d6499ef731 --- /dev/null +++ b/drivers/staging/lustre/lustre/obdclass/lustre_handles.c @@ -0,0 +1,263 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + * GPL HEADER END + */ +/* + * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. + * Use is subject to license terms. + * + * Copyright (c) 2011, 2012, Intel Corporation. + */ +/* + * This file is part of Lustre, http://www.lustre.org/ + * Lustre is a trademark of Sun Microsystems, Inc. + * + * lustre/obdclass/lustre_handles.c + * + * Author: Phil Schwan <phil@clusterfs.com> + */ + +#define DEBUG_SUBSYSTEM S_CLASS + +#include <obd_support.h> +#include <lustre_handles.h> +#include <lustre_lib.h> + + +static __u64 handle_base; +#define HANDLE_INCR 7 +static spinlock_t handle_base_lock; + +static struct handle_bucket { + spinlock_t lock; + struct list_head head; +} *handle_hash; + +#define HANDLE_HASH_SIZE (1 << 16) +#define HANDLE_HASH_MASK (HANDLE_HASH_SIZE - 1) + +/* + * Generate a unique 64bit cookie (hash) for a handle and insert it into + * global (per-node) hash-table. + */ +void class_handle_hash(struct portals_handle *h, + struct portals_handle_ops *ops) +{ + struct handle_bucket *bucket; + ENTRY; + + LASSERT(h != NULL); + LASSERT(list_empty(&h->h_link)); + + /* + * This is fast, but simplistic cookie generation algorithm, it will + * need a re-do at some point in the future for security. + */ + spin_lock(&handle_base_lock); + handle_base += HANDLE_INCR; + + if (unlikely(handle_base == 0)) { + /* + * Cookie of zero is "dangerous", because in many places it's + * assumed that 0 means "unassigned" handle, not bound to any + * object. + */ + CWARN("The universe has been exhausted: cookie wrap-around.\n"); + handle_base += HANDLE_INCR; + } + h->h_cookie = handle_base; + spin_unlock(&handle_base_lock); + + h->h_ops = ops; + spin_lock_init(&h->h_lock); + + bucket = &handle_hash[h->h_cookie & HANDLE_HASH_MASK]; + spin_lock(&bucket->lock); + list_add_rcu(&h->h_link, &bucket->head); + h->h_in = 1; + spin_unlock(&bucket->lock); + + CDEBUG(D_INFO, "added object %p with handle "LPX64" to hash\n", + h, h->h_cookie); + EXIT; +} +EXPORT_SYMBOL(class_handle_hash); + +static void class_handle_unhash_nolock(struct portals_handle *h) +{ + if (list_empty(&h->h_link)) { + CERROR("removing an already-removed handle ("LPX64")\n", + h->h_cookie); + return; + } + + CDEBUG(D_INFO, "removing object %p with handle "LPX64" from hash\n", + h, h->h_cookie); + + spin_lock(&h->h_lock); + if (h->h_in == 0) { + spin_unlock(&h->h_lock); + return; + } + h->h_in = 0; + spin_unlock(&h->h_lock); + list_del_rcu(&h->h_link); +} + +void class_handle_unhash(struct portals_handle *h) +{ + struct handle_bucket *bucket; + bucket = handle_hash + (h->h_cookie & HANDLE_HASH_MASK); + + spin_lock(&bucket->lock); + class_handle_unhash_nolock(h); + spin_unlock(&bucket->lock); +} +EXPORT_SYMBOL(class_handle_unhash); + +void class_handle_hash_back(struct portals_handle *h) +{ + struct handle_bucket *bucket; + ENTRY; + + bucket = handle_hash + (h->h_cookie & HANDLE_HASH_MASK); + + spin_lock(&bucket->lock); + list_add_rcu(&h->h_link, &bucket->head); + h->h_in = 1; + spin_unlock(&bucket->lock); + + EXIT; +} +EXPORT_SYMBOL(class_handle_hash_back); + +void *class_handle2object(__u64 cookie) +{ + struct handle_bucket *bucket; + struct portals_handle *h; + void *retval = NULL; + ENTRY; + + LASSERT(handle_hash != NULL); + + /* Be careful when you want to change this code. See the + * rcu_read_lock() definition on top this file. - jxiong */ + bucket = handle_hash + (cookie & HANDLE_HASH_MASK); + + rcu_read_lock(); + list_for_each_entry_rcu(h, &bucket->head, h_link) { + if (h->h_cookie != cookie) + continue; + + spin_lock(&h->h_lock); + if (likely(h->h_in != 0)) { + h->h_ops->hop_addref(h); + retval = h; + } + spin_unlock(&h->h_lock); + break; + } + rcu_read_unlock(); + + RETURN(retval); +} +EXPORT_SYMBOL(class_handle2object); + +void class_handle_free_cb(cfs_rcu_head_t *rcu) +{ + struct portals_handle *h = RCU2HANDLE(rcu); + void *ptr = (void *)(unsigned long)h->h_cookie; + + if (h->h_ops->hop_free != NULL) + h->h_ops->hop_free(ptr, h->h_size); + else + OBD_FREE(ptr, h->h_size); +} +EXPORT_SYMBOL(class_handle_free_cb); + +int class_handle_init(void) +{ + struct handle_bucket *bucket; + struct timeval tv; + int seed[2]; + + LASSERT(handle_hash == NULL); + + OBD_ALLOC_LARGE(handle_hash, sizeof(*bucket) * HANDLE_HASH_SIZE); + if (handle_hash == NULL) + return -ENOMEM; + + spin_lock_init(&handle_base_lock); + for (bucket = handle_hash + HANDLE_HASH_SIZE - 1; bucket >= handle_hash; + bucket--) { + INIT_LIST_HEAD(&bucket->head); + spin_lock_init(&bucket->lock); + } + + /** bug 21430: add randomness to the initial base */ + cfs_get_random_bytes(seed, sizeof(seed)); + do_gettimeofday(&tv); + cfs_srand(tv.tv_sec ^ seed[0], tv.tv_usec ^ seed[1]); + + cfs_get_random_bytes(&handle_base, sizeof(handle_base)); + LASSERT(handle_base != 0ULL); + + return 0; +} + +static int cleanup_all_handles(void) +{ + int rc; + int i; + + for (rc = i = 0; i < HANDLE_HASH_SIZE; i++) { + struct portals_handle *h; + + spin_lock(&handle_hash[i].lock); + list_for_each_entry_rcu(h, &(handle_hash[i].head), h_link) { + CERROR("force clean handle "LPX64" addr %p ops %p\n", + h->h_cookie, h, h->h_ops); + + class_handle_unhash_nolock(h); + rc++; + } + spin_unlock(&handle_hash[i].lock); + } + + return rc; +} + +void class_handle_cleanup(void) +{ + int count; + LASSERT(handle_hash != NULL); + + count = cleanup_all_handles(); + + OBD_FREE_LARGE(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE); + handle_hash = NULL; + + if (count != 0) + CERROR("handle_count at cleanup: %d\n", count); +} |