-#ifndef _KCOMPAT_RCULIST_H
-#define _KCOMPAT_RCULIST_H
-
/*
- * RCU-protected list version
- *
- * 2002-10-18 19:01:25-07:00, dipankar@in.ibm.com
- * [PATCH] RCU helper patchset 2/2
- *
- * This adds a set of list macros that make handling of list protected
- * by RCU simpler. The interfaces added are -
- *
- * list_add_rcu
- * list_add_tail_rcu
- * - Adds an element by taking care of memory barrier (wmb()).
- *
- * list_del_rcu
- * - Deletes an element but doesn't re-initialize the pointers in
- * the element for supporting RCU based traversal.
- *
- * list_for_each_rcu
- * __list_for_each_rcu
- * - Traversal of RCU protected list - takes care of memory barriers
- * transparently.
- *
+ * Copyright (C) 2002 Free Software Foundation, Inc.
+ * (originally part of the GNU C Library)
+ * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+ *
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Conversion to RCU list.
+ * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#define _LGPL_SOURCE
-#include <urcu.h>
-#include <kcompat/list.h>
+#ifndef _URCU_RCULIST_H
+#define _URCU_RCULIST_H
-/*
- * Insert a new entry between two known consecutive entries.
- *
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
- */
-static __inline__ void __list_add_rcu(struct list_head * new,
- struct list_head * prev,
- struct list_head * next)
+#include <urcu/list.h>
+#include <urcu/arch.h>
+#include <urcu-pointer.h>
+
+/* Add new element at the head of the list. */
+static inline
+void cds_list_add_rcu(struct cds_list_head *newp, struct cds_list_head *head)
{
- new->next = next;
- new->prev = prev;
- smp_wmb();
- next->prev = new;
- prev->next = new;
+ newp->next = head->next;
+ newp->prev = head;
+ head->next->prev = newp;
+ rcu_assign_pointer(head->next, newp);
}
-/**
- * list_add_rcu - add a new entry to rcu-protected list
- * @new: new entry to be added
- * @head: list head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_add_rcu()
- * or list_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
- */
-static __inline__ void list_add_rcu(struct list_head *new,
- struct list_head *head)
+/* Add new element at the tail of the list. */
+static inline
+void cds_list_add_tail_rcu(struct cds_list_head *newp,
+ struct cds_list_head *head)
{
- __list_add_rcu(new, head, head->next);
+ newp->next = head;
+ newp->prev = head->prev;
+ rcu_assign_pointer(head->prev->next, newp);
+ head->prev = newp;
}
-/**
- * list_add_tail_rcu - add a new entry to rcu-protected list
- * @new: new entry to be added
- * @head: list head to add it before
- *
- * Insert a new entry before the specified head.
- * This is useful for implementing queues.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_add_tail_rcu()
- * or list_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
+/*
+ * Replace an old entry atomically with respect to concurrent RCU
+ * traversal. Mutual exclusion against concurrent updates is required
+ * though.
*/
-static __inline__ void list_add_tail_rcu(struct list_head *new,
- struct list_head *head)
+static inline
+void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
{
- __list_add_rcu(new, head->prev, head);
+ _new->next = old->next;
+ _new->prev = old->prev;
+ rcu_assign_pointer(_new->prev->next, _new);
+ _new->next->prev = _new;
}
-/**
- * list_del_rcu - deletes entry from list without re-initialization
- * @entry: the element to delete from the list.
- *
- * Note: list_empty on entry does not return true after this,
- * the entry is in an undefined state. It is useful for RCU based
- * lockfree traversal.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_del_rcu()
- * or list_add_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
- *
- * Note that the caller is not permitted to immediately free
- * the newly deleted entry. Instead, either synchronize_kernel()
- * or call_rcu() must be used to defer freeing until an RCU
- * grace period has elapsed.
- */
-static inline void list_del_rcu(struct list_head *entry)
+/* Remove element from list. */
+static inline
+void cds_list_del_rcu(struct cds_list_head *elem)
{
- __list_del(entry->prev, entry->next);
+ elem->next->prev = elem->prev;
+ CMM_STORE_SHARED(elem->prev->next, elem->next);
}
-/**
- * list_for_each_rcu - iterate over an rcu-protected list
- * @pos: the &struct list_head to use as a loop counter.
- * @head: the head for your list.
- *
- * This list-traversal primitive may safely run concurrently with
- * the _rcu list-mutation primitives such as list_add_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
+/*
+ * Iteration through all elements of the list must be done while rcu_read_lock()
+ * is held.
*/
-#define list_for_each_rcu(pos, head) \
- for (pos = rcu_dereference((head)->next); \
- prefetch(pos->next), pos != (head); \
- pos = rcu_dereference(pos->next))
-#define __list_for_each_rcu(pos, head) \
- for (pos = rcu_dereference((head)->next); \
- pos != (head); \
- pos = rcu_dereference(pos->next))
+/* Iterate forward over the elements of the list. */
+#define cds_list_for_each_rcu(pos, head) \
+ for (pos = rcu_dereference((head)->next); pos != (head); \
+ pos = rcu_dereference(pos->next))
-/**
- * list_for_each_entry_rcu - iterate over a rcu-protected list
- * @pos: the struct type pointer to use as a loop counter
- * @head: the head for your list
- * @member: the name of the struct list_head element in your struct type
- *
- * This list-traversal primitive may safely run concurrently with
- * the _rcu list-mutation primitives such as list_add_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
- */
-#define list_for_each_entry_rcu(pos, head, member) \
- for (pos = list_entry(rcu_dereference((head)->next), typeof(*pos), \
- member); \
- prefetch(pos->member.next), &pos->member != (head); \
- pos = list_entry(rcu_dereference(pos->member.next),typeof(*pos), \
- member))
-#endif /* _KCOMPAT_RCULIST_H */
+/* Iterate through elements of the list. */
+#define cds_list_for_each_entry_rcu(pos, head, member) \
+ for (pos = cds_list_entry(rcu_dereference((head)->next), __typeof__(*pos), member); \
+ &pos->member != (head); \
+ pos = cds_list_entry(rcu_dereference(pos->member.next), __typeof__(*pos), member))
+
+#endif /* _URCU_RCULIST_H */
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