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LU-3963 obdclass: convert to linux list api
[fs/lustre-release.git] / lustre / obdclass / lustre_handles.c
index 21d6f50..e4dc355 100644 (file)
@@ -1,26 +1,41 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
+/*
+ * 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).
  *
- * Copyright (C) 2002 Cluster File Systems, Inc.
- *   Author: Phil Schwan <phil@clusterfs.com>
+ * 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
  *
- *   This file is part of the Lustre file system, http://www.lustre.org
- *   Lustre is a trademark of Cluster File Systems, Inc.
+ * 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.
  *
- *   You may have signed or agreed to another license before downloading
- *   this software.  If so, you are bound by the terms and conditions
- *   of that agreement, and the following does not apply to you.  See the
- *   LICENSE file included with this distribution for more information.
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2013, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
  *
- *   If you did not agree to a different license, then this copy of Lustre
- *   is open source software; you can redistribute it and/or modify it
- *   under the terms of version 2 of the GNU General Public License as
- *   published by the Free Software Foundation.
+ * lustre/obdclass/lustre_handles.c
  *
- *   In either case, Lustre 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
- *   license text for more details.
+ * Author: Phil Schwan <phil@clusterfs.com>
  */
 
 #define DEBUG_SUBSYSTEM S_CLASS
 
 #include <obd_support.h>
 #include <lustre_handles.h>
+#include <lustre_lib.h>
+
+#ifndef __KERNEL__
+# define list_add_rcu            list_add
+# define list_del_rcu            list_del
+# define list_for_each_rcu       list_for_each
+# define list_for_each_safe_rcu  list_for_each_safe
+# define list_for_each_entry_rcu list_for_each_entry
+# define rcu_read_lock()         spin_lock(&bucket->lock)
+# define rcu_read_unlock()       spin_unlock(&bucket->lock)
+#endif /* !__KERNEL__ */
 
-spinlock_t handle_lock;
 static __u64 handle_base;
 #define HANDLE_INCR 7
-static struct list_head *handle_hash = NULL;
-static int handle_count = 0;
+static spinlock_t handle_base_lock;
+
+static struct handle_bucket {
+       spinlock_t       lock;
+       struct list_head head;
+} *handle_hash;
 
-#define HANDLE_HASH_SIZE (1 << 14)
+#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, portals_handle_addref_cb cb)
+void class_handle_hash(struct portals_handle *h,
+                      struct portals_handle_ops *ops)
 {
-        struct list_head *bucket;
+        struct handle_bucket *bucket;
         ENTRY;
 
         LASSERT(h != NULL);
-        LASSERT(list_empty(&h->h_link));
-
-        spin_lock(&handle_lock);
+       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.
          */
-        h->h_cookie = handle_base;
-        handle_base += HANDLE_INCR;
-
-        bucket = handle_hash + (h->h_cookie & HANDLE_HASH_MASK);
-        list_add(&h->h_link, bucket);
-        handle_count++;
-
-        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;
-        }
-
-        spin_unlock(&handle_lock);
-
-        h->h_addref = cb;
-        CDEBUG(D_INFO, "added object %p with handle "LPX64" to hash\n",
-               h, h->h_cookie);
-        EXIT;
+       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)) {
+       if (list_empty(&h->h_link)) {
                 CERROR("removing an already-removed handle ("LPX64")\n",
                        h->h_cookie);
                 return;
@@ -94,95 +127,149 @@ static void class_handle_unhash_nolock(struct portals_handle *h)
         CDEBUG(D_INFO, "removing object %p with handle "LPX64" from hash\n",
                h, h->h_cookie);
 
-        handle_count--;
-        list_del_init(&h->h_link);
+       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)
 {
-        spin_lock(&handle_lock);
-        class_handle_unhash_nolock(h);
-        spin_unlock(&handle_lock);
+       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)
+void *class_handle2object(__u64 cookie, const void *owner)
 {
-        struct list_head *bucket, *tmp;
+        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);
 
-        spin_lock(&handle_lock);
-        list_for_each(tmp, bucket) {
-                struct portals_handle *h;
-                h = list_entry(tmp, struct portals_handle, h_link);
+        rcu_read_lock();
+        list_for_each_entry_rcu(h, &bucket->head, h_link) {
+               if (h->h_cookie != cookie || h->h_owner != owner)
+                        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);
 
-                if (h->h_cookie == cookie) {
-                        h->h_addref(h);
-                        retval = h;
-                        break;
-                }
-        }
-        spin_unlock(&handle_lock);
+void class_handle_free_cb(cfs_rcu_head_t *rcu)
+{
+       struct portals_handle *h = RCU2HANDLE(rcu);
+       void *ptr = (void *)(unsigned long)h->h_cookie;
 
-        RETURN(retval);
+       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 list_head *bucket;
+        struct handle_bucket *bucket;
+        struct timeval tv;
+        int seed[2];
 
         LASSERT(handle_hash == NULL);
 
-        OBD_VMALLOC(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE);
+        OBD_ALLOC_LARGE(handle_hash, sizeof(*bucket) * HANDLE_HASH_SIZE);
         if (handle_hash == NULL)
                 return -ENOMEM;
 
-        for (bucket = handle_hash + HANDLE_HASH_SIZE - 1; bucket >= handle_hash;
-             bucket--)
-                CFS_INIT_LIST_HEAD(bucket);
+       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]);
 
-        get_random_bytes(&handle_base, sizeof(handle_base));
+        cfs_get_random_bytes(&handle_base, sizeof(handle_base));
         LASSERT(handle_base != 0ULL);
 
         return 0;
 }
 
-static void cleanup_all_handles(void)
+static int cleanup_all_handles(void)
 {
-        int i;
+       int rc;
+       int i;
 
-        spin_lock(&handle_lock);
-        for (i = 0; i < HANDLE_HASH_SIZE; i++) {
-                struct list_head *tmp, *pos;
-                list_for_each_safe(tmp, pos, &(handle_hash[i])) {
-                        struct portals_handle *h;
-                        h = list_entry(tmp, struct portals_handle, h_link);
+       for (rc = i = 0; i < HANDLE_HASH_SIZE; i++) {
+               struct portals_handle *h;
 
-                        CERROR("force clean handle "LPX64" addr %p addref %p\n",
-                               h->h_cookie, h, h->h_addref);
+               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);
-                }
-        }
-        spin_unlock(&handle_lock);
+                       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);
 
-        if (handle_count != 0) {
-                CERROR("handle_count at cleanup: %d\n", handle_count);
-                cleanup_all_handles();
-        }
+        count = cleanup_all_handles();
 
-        OBD_VFREE(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE);
+        OBD_FREE_LARGE(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE);
         handle_hash = NULL;
 
-        if (handle_count)
-                CERROR("leaked %d handles\n", handle_count);
+        if (count != 0)
+                CERROR("handle_count at cleanup: %d\n", count);
 }