+++ /dev/null
-/*
- * CDDL HEADER START
- *
- * The contents of this file are subject to the terms of the
- * Common Development and Distribution License (the "License").
- * You may not use this file except in compliance with the License.
- *
- * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
- * or http://www.opensolaris.org/os/licensing.
- * See the License for the specific language governing permissions
- * and limitations under the License.
- *
- * When distributing Covered Code, include this CDDL HEADER in each
- * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
- * If applicable, add the following below this CDDL HEADER, with the
- * fields enclosed by brackets "[]" replaced with your own identifying
- * information: Portions Copyright [yyyy] [name of copyright owner]
- *
- * CDDL HEADER END
- */
-/*
- * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
- */
-
-#include <sys/zfs_context.h>
-#include <sys/refcount.h>
-
-#ifdef _KERNEL
-int reference_tracking_enable = FALSE; /* runs out of memory too easily */
-#else
-int reference_tracking_enable = TRUE;
-#endif
-int reference_history = 3; /* tunable */
-
-#ifdef ZFS_DEBUG
-static kmem_cache_t *reference_cache;
-static kmem_cache_t *reference_history_cache;
-
-void
-refcount_init(void)
-{
- reference_cache = kmem_cache_create("reference_cache",
- sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
-
- reference_history_cache = kmem_cache_create("reference_history_cache",
- sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
-}
-
-void
-refcount_fini(void)
-{
- kmem_cache_destroy(reference_cache);
- kmem_cache_destroy(reference_history_cache);
-}
-
-void
-refcount_create(refcount_t *rc)
-{
- mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL);
- list_create(&rc->rc_list, sizeof (reference_t),
- offsetof(reference_t, ref_link));
- list_create(&rc->rc_removed, sizeof (reference_t),
- offsetof(reference_t, ref_link));
- rc->rc_count = 0;
- rc->rc_removed_count = 0;
- rc->rc_tracked = reference_tracking_enable;
-}
-
-void
-refcount_create_tracked(refcount_t *rc)
-{
- refcount_create(rc);
- rc->rc_tracked = B_TRUE;
-}
-
-void
-refcount_create_untracked(refcount_t *rc)
-{
- refcount_create(rc);
- rc->rc_tracked = B_FALSE;
-}
-
-void
-refcount_destroy_many(refcount_t *rc, uint64_t number)
-{
- reference_t *ref;
-
- ASSERT(rc->rc_count == number);
- while ((ref = list_head(&rc->rc_list))) {
- list_remove(&rc->rc_list, ref);
- kmem_cache_free(reference_cache, ref);
- }
- list_destroy(&rc->rc_list);
-
- while ((ref = list_head(&rc->rc_removed))) {
- list_remove(&rc->rc_removed, ref);
- kmem_cache_free(reference_history_cache, ref->ref_removed);
- kmem_cache_free(reference_cache, ref);
- }
- list_destroy(&rc->rc_removed);
- mutex_destroy(&rc->rc_mtx);
-}
-
-void
-refcount_destroy(refcount_t *rc)
-{
- refcount_destroy_many(rc, 0);
-}
-
-int
-refcount_is_zero(refcount_t *rc)
-{
- return (rc->rc_count == 0);
-}
-
-int64_t
-refcount_count(refcount_t *rc)
-{
- return (rc->rc_count);
-}
-
-int64_t
-refcount_add_many(refcount_t *rc, uint64_t number, void *holder)
-{
- reference_t *ref = NULL;
- int64_t count;
-
- if (rc->rc_tracked) {
- ref = kmem_cache_alloc(reference_cache, KM_SLEEP);
- ref->ref_holder = holder;
- ref->ref_number = number;
- }
- mutex_enter(&rc->rc_mtx);
- ASSERT(rc->rc_count >= 0);
- if (rc->rc_tracked)
- list_insert_head(&rc->rc_list, ref);
- rc->rc_count += number;
- count = rc->rc_count;
- mutex_exit(&rc->rc_mtx);
-
- return (count);
-}
-
-int64_t
-zfs_refcount_add(refcount_t *rc, void *holder)
-{
- return (refcount_add_many(rc, 1, holder));
-}
-
-int64_t
-refcount_remove_many(refcount_t *rc, uint64_t number, void *holder)
-{
- reference_t *ref;
- int64_t count;
-
- mutex_enter(&rc->rc_mtx);
- ASSERT(rc->rc_count >= number);
-
- if (!rc->rc_tracked) {
- rc->rc_count -= number;
- count = rc->rc_count;
- mutex_exit(&rc->rc_mtx);
- return (count);
- }
-
- for (ref = list_head(&rc->rc_list); ref;
- ref = list_next(&rc->rc_list, ref)) {
- if (ref->ref_holder == holder && ref->ref_number == number) {
- list_remove(&rc->rc_list, ref);
- if (reference_history > 0) {
- ref->ref_removed =
- kmem_cache_alloc(reference_history_cache,
- KM_SLEEP);
- list_insert_head(&rc->rc_removed, ref);
- rc->rc_removed_count++;
- if (rc->rc_removed_count > reference_history) {
- ref = list_tail(&rc->rc_removed);
- list_remove(&rc->rc_removed, ref);
- kmem_cache_free(reference_history_cache,
- ref->ref_removed);
- kmem_cache_free(reference_cache, ref);
- rc->rc_removed_count--;
- }
- } else {
- kmem_cache_free(reference_cache, ref);
- }
- rc->rc_count -= number;
- count = rc->rc_count;
- mutex_exit(&rc->rc_mtx);
- return (count);
- }
- }
- panic("No such hold %p on refcount %llx", holder,
- (u_longlong_t)(uintptr_t)rc);
- return (-1);
-}
-
-int64_t
-refcount_remove(refcount_t *rc, void *holder)
-{
- return (refcount_remove_many(rc, 1, holder));
-}
-
-void
-refcount_transfer(refcount_t *dst, refcount_t *src)
-{
- int64_t count, removed_count;
- list_t list, removed;
-
- list_create(&list, sizeof (reference_t),
- offsetof(reference_t, ref_link));
- list_create(&removed, sizeof (reference_t),
- offsetof(reference_t, ref_link));
-
- mutex_enter(&src->rc_mtx);
- count = src->rc_count;
- removed_count = src->rc_removed_count;
- src->rc_count = 0;
- src->rc_removed_count = 0;
- list_move_tail(&list, &src->rc_list);
- list_move_tail(&removed, &src->rc_removed);
- mutex_exit(&src->rc_mtx);
-
- mutex_enter(&dst->rc_mtx);
- dst->rc_count += count;
- dst->rc_removed_count += removed_count;
- list_move_tail(&dst->rc_list, &list);
- list_move_tail(&dst->rc_removed, &removed);
- mutex_exit(&dst->rc_mtx);
-
- list_destroy(&list);
- list_destroy(&removed);
-}
-
-void
-refcount_transfer_ownership(refcount_t *rc, void *current_holder,
- void *new_holder)
-{
- reference_t *ref;
- boolean_t found = B_FALSE;
-
- mutex_enter(&rc->rc_mtx);
- if (!rc->rc_tracked) {
- mutex_exit(&rc->rc_mtx);
- return;
- }
-
- for (ref = list_head(&rc->rc_list); ref;
- ref = list_next(&rc->rc_list, ref)) {
- if (ref->ref_holder == current_holder) {
- ref->ref_holder = new_holder;
- found = B_TRUE;
- break;
- }
- }
- ASSERT(found);
- mutex_exit(&rc->rc_mtx);
-}
-
-/*
- * If tracking is enabled, return true if a reference exists that matches
- * the "holder" tag. If tracking is disabled, then return true if a reference
- * might be held.
- */
-boolean_t
-refcount_held(refcount_t *rc, void *holder)
-{
- reference_t *ref;
-
- mutex_enter(&rc->rc_mtx);
-
- if (!rc->rc_tracked) {
- mutex_exit(&rc->rc_mtx);
- return (rc->rc_count > 0);
- }
-
- for (ref = list_head(&rc->rc_list); ref;
- ref = list_next(&rc->rc_list, ref)) {
- if (ref->ref_holder == holder) {
- mutex_exit(&rc->rc_mtx);
- return (B_TRUE);
- }
- }
- mutex_exit(&rc->rc_mtx);
- return (B_FALSE);
-}
-
-/*
- * If tracking is enabled, return true if a reference does not exist that
- * matches the "holder" tag. If tracking is disabled, always return true
- * since the reference might not be held.
- */
-boolean_t
-refcount_not_held(refcount_t *rc, void *holder)
-{
- reference_t *ref;
-
- mutex_enter(&rc->rc_mtx);
-
- if (!rc->rc_tracked) {
- mutex_exit(&rc->rc_mtx);
- return (B_TRUE);
- }
-
- for (ref = list_head(&rc->rc_list); ref;
- ref = list_next(&rc->rc_list, ref)) {
- if (ref->ref_holder == holder) {
- mutex_exit(&rc->rc_mtx);
- return (B_FALSE);
- }
- }
- mutex_exit(&rc->rc_mtx);
- return (B_TRUE);
-}
-#endif /* ZFS_DEBUG */
projects / mirror_ubuntu-bionic-kernel.git / blobdiff