+++ /dev/null
-#ifndef _URCU_WFSTACK_H
-#define _URCU_WFSTACK_H
-
-/*
- * urcu/wfstack.h
- *
- * Userspace RCU library - Stack with wait-free push, blocking traversal.
- *
- * Copyright 2010-2012 - 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
- */
-
-#include <pthread.h>
-#include <assert.h>
-#include <stdbool.h>
-#include <urcu/compiler.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/*
- * Stack with wait-free push, blocking traversal.
- *
- * Stack implementing push, pop, pop_all operations, as well as iterator
- * on the stack head returned by pop_all.
- *
- * Wait-free operations: cds_wfs_push, __cds_wfs_pop_all, cds_wfs_empty,
- * cds_wfs_first.
- * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, cds_wfs_next,
- * iteration on stack head returned by pop_all.
- *
- * Synchronization table:
- *
- * External synchronization techniques described in the API below is
- * required between pairs marked with "X". No external synchronization
- * required between pairs marked with "-".
- *
- * cds_wfs_push __cds_wfs_pop __cds_wfs_pop_all
- * cds_wfs_push - - -
- * __cds_wfs_pop - X X
- * __cds_wfs_pop_all - X -
- *
- * cds_wfs_pop and cds_wfs_pop_all use an internal mutex to provide
- * synchronization.
- */
-
-#define CDS_WFS_WOULDBLOCK ((void *) -1UL)
-
-enum cds_wfs_state {
- CDS_WFS_STATE_LAST = (1U << 0),
-};
-
-/*
- * struct cds_wfs_node is returned by __cds_wfs_pop, and also used as
- * iterator on stack. It is not safe to dereference the node next
- * pointer when returned by __cds_wfs_pop_blocking.
- */
-struct cds_wfs_node {
- struct cds_wfs_node *next;
-};
-
-/*
- * struct cds_wfs_head is returned by __cds_wfs_pop_all, and can be used
- * to begin iteration on the stack. "node" needs to be the first field of
- * cds_wfs_head, so the end-of-stack pointer value can be used for both
- * types.
- */
-struct cds_wfs_head {
- struct cds_wfs_node node;
-};
-
-struct __cds_wfs_stack {
- struct cds_wfs_head *head;
-};
-
-struct cds_wfs_stack {
- struct cds_wfs_head *head;
- pthread_mutex_t lock;
-};
-
-/*
- * The transparent union allows calling functions that work on both
- * struct cds_wfs_stack and struct __cds_wfs_stack on any of those two
- * types.
- */
-typedef union {
- struct __cds_wfs_stack *_s;
- struct cds_wfs_stack *s;
-} __attribute__((__transparent_union__)) cds_wfs_stack_ptr_t;
-
-#ifdef _LGPL_SOURCE
-
-#include <urcu/static/wfstack.h>
-
-#define cds_wfs_node_init _cds_wfs_node_init
-#define cds_wfs_init _cds_wfs_init
-#define cds_wfs_destroy _cds_wfs_destroy
-#define __cds_wfs_init ___cds_wfs_init
-#define cds_wfs_empty _cds_wfs_empty
-#define cds_wfs_push _cds_wfs_push
-
-/* Locking performed internally */
-#define cds_wfs_pop_blocking _cds_wfs_pop_blocking
-#define cds_wfs_pop_with_state_blocking _cds_wfs_pop_with_state_blocking
-#define cds_wfs_pop_all_blocking _cds_wfs_pop_all_blocking
-
-/*
- * For iteration on cds_wfs_head returned by __cds_wfs_pop_all or
- * cds_wfs_pop_all_blocking.
- */
-#define cds_wfs_first _cds_wfs_first
-#define cds_wfs_next_blocking _cds_wfs_next_blocking
-#define cds_wfs_next_nonblocking _cds_wfs_next_nonblocking
-
-/* Pop locking with internal mutex */
-#define cds_wfs_pop_lock _cds_wfs_pop_lock
-#define cds_wfs_pop_unlock _cds_wfs_pop_unlock
-
-/* Synchronization ensured by the caller. See synchronization table. */
-#define __cds_wfs_pop_blocking ___cds_wfs_pop_blocking
-#define __cds_wfs_pop_with_state_blocking \
- ___cds_wfs_pop_with_state_blocking
-#define __cds_wfs_pop_nonblocking ___cds_wfs_pop_nonblocking
-#define __cds_wfs_pop_with_state_nonblocking \
- ___cds_wfs_pop_with_state_nonblocking
-#define __cds_wfs_pop_all ___cds_wfs_pop_all
-
-#else /* !_LGPL_SOURCE */
-
-/*
- * cds_wfs_node_init: initialize wait-free stack node.
- */
-extern void cds_wfs_node_init(struct cds_wfs_node *node);
-
-/*
- * cds_wfs_init: initialize wait-free stack (with lock). Pair with
- * cds_wfs_destroy().
- */
-extern void cds_wfs_init(struct cds_wfs_stack *s);
-
-/*
- * cds_wfs_destroy: destroy wait-free stack (with lock). Pair with
- * cds_wfs_init().
- */
-extern void cds_wfs_destroy(struct cds_wfs_stack *s);
-
-/*
- * __cds_wfs_init: initialize wait-free stack (no lock). Don't pair with
- * any destroy function.
- */
-extern void __cds_wfs_init(struct __cds_wfs_stack *s);
-
-/*
- * cds_wfs_empty: return whether wait-free stack is empty.
- *
- * No memory barrier is issued. No mutual exclusion is required.
- */
-extern bool cds_wfs_empty(cds_wfs_stack_ptr_t u_stack);
-
-/*
- * cds_wfs_push: push a node into the stack.
- *
- * Issues a full memory barrier before push. No mutual exclusion is
- * required.
- *
- * Returns 0 if the stack was empty prior to adding the node.
- * Returns non-zero otherwise.
- */
-extern int cds_wfs_push(cds_wfs_stack_ptr_t u_stack, struct cds_wfs_node *node);
-
-/*
- * cds_wfs_pop_blocking: pop a node from the stack.
- *
- * Calls __cds_wfs_pop_blocking with an internal pop mutex held.
- */
-extern struct cds_wfs_node *cds_wfs_pop_blocking(struct cds_wfs_stack *s);
-
-/*
- * cds_wfs_pop_with_state_blocking: pop a node from the stack, with state.
- *
- * Same as cds_wfs_pop_blocking, but stores whether the stack was
- * empty into state (CDS_WFS_STATE_LAST).
- */
-extern struct cds_wfs_node *
- cds_wfs_pop_with_state_blocking(struct cds_wfs_stack *s, int *state);
-
-/*
- * cds_wfs_pop_all_blocking: pop all nodes from a stack.
- *
- * Calls __cds_wfs_pop_all with an internal pop mutex held.
- */
-extern struct cds_wfs_head *cds_wfs_pop_all_blocking(struct cds_wfs_stack *s);
-
-/*
- * cds_wfs_first: get first node of a popped stack.
- *
- * Content written into the node before enqueue is guaranteed to be
- * consistent, but no other memory ordering is ensured.
- *
- * Used by for-like iteration macros in urcu/wfstack.h:
- * cds_wfs_for_each_blocking()
- * cds_wfs_for_each_blocking_safe()
- *
- * Returns NULL if popped stack is empty, top stack node otherwise.
- */
-extern struct cds_wfs_node *cds_wfs_first(struct cds_wfs_head *head);
-
-/*
- * cds_wfs_next_blocking: get next node of a popped stack.
- *
- * Content written into the node before enqueue is guaranteed to be
- * consistent, but no other memory ordering is ensured.
- *
- * Used by for-like iteration macros in urcu/wfstack.h:
- * cds_wfs_for_each_blocking()
- * cds_wfs_for_each_blocking_safe()
- *
- * Returns NULL if reached end of popped stack, non-NULL next stack
- * node otherwise.
- */
-extern struct cds_wfs_node *cds_wfs_next_blocking(struct cds_wfs_node *node);
-
-/*
- * cds_wfs_next_nonblocking: get next node of a popped stack.
- *
- * Same as cds_wfs_next_blocking, but returns CDS_WFS_WOULDBLOCK if it
- * needs to block.
- */
-extern struct cds_wfs_node *cds_wfs_next_nonblocking(struct cds_wfs_node *node);
-
-/*
- * cds_wfs_pop_lock: lock stack pop-protection mutex.
- */
-extern void cds_wfs_pop_lock(struct cds_wfs_stack *s);
-
-/*
- * cds_wfs_pop_unlock: unlock stack pop-protection mutex.
- */
-extern void cds_wfs_pop_unlock(struct cds_wfs_stack *s);
-
-/*
- * __cds_wfs_pop_blocking: pop a node from the stack.
- *
- * Returns NULL if stack is empty.
- *
- * __cds_wfs_pop_blocking needs to be synchronized using one of the
- * following techniques:
- *
- * 1) Calling __cds_wfs_pop_blocking under rcu read lock critical
- * section. The caller must wait for a grace period to pass before
- * freeing the returned node or modifying the cds_wfs_node structure.
- * 2) Using mutual exclusion (e.g. mutexes) to protect
- * __cds_wfs_pop_blocking and __cds_wfs_pop_all callers.
- * 3) Ensuring that only ONE thread can call __cds_wfs_pop_blocking()
- * and __cds_wfs_pop_all(). (multi-provider/single-consumer scheme).
- */
-extern struct cds_wfs_node *__cds_wfs_pop_blocking(cds_wfs_stack_ptr_t u_stack);
-
-/*
- * __cds_wfs_pop_with_state_blocking: pop a node from the stack, with state.
- *
- * Same as __cds_wfs_pop_blocking, but stores whether the stack was
- * empty into state (CDS_WFS_STATE_LAST).
- */
-extern struct cds_wfs_node *
- __cds_wfs_pop_with_state_blocking(cds_wfs_stack_ptr_t u_stack,
- int *state);
-
-/*
- * __cds_wfs_pop_nonblocking: pop a node from the stack.
- *
- * Same as __cds_wfs_pop_blocking, but returns CDS_WFS_WOULDBLOCK if
- * it needs to block.
- */
-extern struct cds_wfs_node *__cds_wfs_pop_nonblocking(cds_wfs_stack_ptr_t u_stack);
-
-/*
- * __cds_wfs_pop_with_state_nonblocking: pop a node from the stack, with state.
- *
- * Same as __cds_wfs_pop_nonblocking, but stores whether the stack was
- * empty into state (CDS_WFS_STATE_LAST).
- */
-extern struct cds_wfs_node *
- __cds_wfs_pop_with_state_nonblocking(cds_wfs_stack_ptr_t u_stack,
- int *state);
-
-/*
- * __cds_wfs_pop_all: pop all nodes from a stack.
- *
- * __cds_wfs_pop_all does not require any synchronization with other
- * push, nor with other __cds_wfs_pop_all, but requires synchronization
- * matching the technique used to synchronize __cds_wfs_pop_blocking:
- *
- * 1) If __cds_wfs_pop_blocking is called under rcu read lock critical
- * section, both __cds_wfs_pop_blocking and cds_wfs_pop_all callers
- * must wait for a grace period to pass before freeing the returned
- * node or modifying the cds_wfs_node structure. However, no RCU
- * read-side critical section is needed around __cds_wfs_pop_all.
- * 2) Using mutual exclusion (e.g. mutexes) to protect
- * __cds_wfs_pop_blocking and __cds_wfs_pop_all callers.
- * 3) Ensuring that only ONE thread can call __cds_wfs_pop_blocking()
- * and __cds_wfs_pop_all(). (multi-provider/single-consumer scheme).
- */
-extern struct cds_wfs_head *__cds_wfs_pop_all(cds_wfs_stack_ptr_t u_stack);
-
-#endif /* !_LGPL_SOURCE */
-
-#ifdef __cplusplus
-}
-#endif
-
-/*
- * cds_wfs_for_each_blocking: Iterate over all nodes returned by
- * __cds_wfs_pop_all().
- * @head: head of the queue (struct cds_wfs_head pointer).
- * @node: iterator (struct cds_wfs_node pointer).
- *
- * Content written into each node before enqueue is guaranteed to be
- * consistent, but no other memory ordering is ensured.
- */
-#define cds_wfs_for_each_blocking(head, node) \
- for (node = cds_wfs_first(head); \
- node != NULL; \
- node = cds_wfs_next_blocking(node))
-
-/*
- * cds_wfs_for_each_blocking_safe: Iterate over all nodes returned by
- * __cds_wfs_pop_all(). Safe against deletion.
- * @head: head of the queue (struct cds_wfs_head pointer).
- * @node: iterator (struct cds_wfs_node pointer).
- * @n: struct cds_wfs_node pointer holding the next pointer (used
- * internally).
- *
- * Content written into each node before enqueue is guaranteed to be
- * consistent, but no other memory ordering is ensured.
- */
-#define cds_wfs_for_each_blocking_safe(head, node, n) \
- for (node = cds_wfs_first(head), \
- n = (node ? cds_wfs_next_blocking(node) : NULL); \
- node != NULL; \
- node = n, n = (node ? cds_wfs_next_blocking(node) : NULL))
-
-#endif /* _URCU_WFSTACK_H */
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