--- /dev/null
+/*
+ * 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 "../include/obd_support.h"
+#include "../include/lustre_handles.h"
+#include "../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;
+
+ 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 %#llx to hash\n",
+ h, h->h_cookie);
+}
+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 (%#llx)\n",
+ h->h_cookie);
+ return;
+ }
+
+ CDEBUG(D_INFO, "removing object %p with handle %#llx 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;
+
+ 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);
+}
+EXPORT_SYMBOL(class_handle_hash_back);
+
+void *class_handle2object(__u64 cookie)
+{
+ struct handle_bucket *bucket;
+ struct portals_handle *h;
+ void *retval = NULL;
+
+ 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(struct rcu_head *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 %#llx 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);
+}
Code Review / kvmfornfv.git / blobdiff