lfstack: Implement mutex-free stack head with transparent union (v2)

[urcu.git] / urcu / lfstack.h

diff --git a/urcu/lfstack.h b/urcu/lfstack.h
index eddff0ef519be68d97776b3195054a07c845f2af..9f384d6b323b471bbeb96fb45d511038220e67c5 100644 (file)
--- a/urcu/lfstack.h
+++ b/urcu/lfstack.h
@@ -70,11 +70,25 @@ struct cds_lfs_head {
        struct cds_lfs_node node;
 };
 
        struct cds_lfs_node node;
 };
 

+struct __cds_lfs_stack {
+       struct cds_lfs_head *head;
+};
+

 struct cds_lfs_stack {
        struct cds_lfs_head *head;
        pthread_mutex_t lock;
 };
 
 struct cds_lfs_stack {
        struct cds_lfs_head *head;
        pthread_mutex_t lock;
 };
 

+/*
+ * The transparent union allows calling functions that work on both
+ * struct cds_lfs_stack and struct __cds_lfs_stack on any of those two
+ * types.
+ */
+typedef union __attribute__((__transparent_union__)) {
+       struct __cds_lfs_stack *_s;
+       struct cds_lfs_stack *s;
+} cds_lfs_stack_ptr_t;
+

 #ifdef _LGPL_SOURCE
 
 #include <urcu/static/lfstack.h>
 #ifdef _LGPL_SOURCE
 
 #include <urcu/static/lfstack.h>


@@ -108,12 +122,17 @@ extern void cds_lfs_node_init(struct cds_lfs_node *node);
  */
 extern void cds_lfs_init(struct cds_lfs_stack *s);
 
  */
 extern void cds_lfs_init(struct cds_lfs_stack *s);
 

+/*
+ * __cds_lfs_init: initialize lock-free stack.
+ */
+extern void __cds_lfs_init(struct __cds_lfs_stack *s);
+

 /*
  * cds_lfs_empty: return whether lock-free stack is empty.
  *
  * No memory barrier is issued. No mutual exclusion is required.
  */
 /*
  * cds_lfs_empty: return whether lock-free stack is empty.
  *
  * No memory barrier is issued. No mutual exclusion is required.
  */

-extern bool cds_lfs_empty(struct cds_lfs_stack *s);
+extern bool cds_lfs_empty(cds_lfs_stack_ptr_t s);

 
 /*
  * cds_lfs_push: push a node into the stack.
 
 /*
  * cds_lfs_push: push a node into the stack.


@@ -123,7 +142,7 @@ extern bool cds_lfs_empty(struct cds_lfs_stack *s);
  * Returns 0 if the stack was empty prior to adding the node.
  * Returns non-zero otherwise.
  */
  * Returns 0 if the stack was empty prior to adding the node.
  * Returns non-zero otherwise.
  */

-extern bool cds_lfs_push(struct cds_lfs_stack *s,
+extern bool cds_lfs_push(cds_lfs_stack_ptr_t s,

                        struct cds_lfs_node *node);
 
 /*
                        struct cds_lfs_node *node);
 
 /*


@@ -166,7 +185,7 @@ extern void cds_lfs_pop_unlock(struct cds_lfs_stack *s);
  * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and
  *    __cds_lfs_pop_all(). (multi-provider/single-consumer scheme).
  */
  * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and
  *    __cds_lfs_pop_all(). (multi-provider/single-consumer scheme).
  */

-extern struct cds_lfs_node *__cds_lfs_pop(struct cds_lfs_stack *s);
+extern struct cds_lfs_node *__cds_lfs_pop(cds_lfs_stack_ptr_t s);

 
 /*
  * __cds_lfs_pop_all: pop all nodes from a stack.
 
 /*
  * __cds_lfs_pop_all: pop all nodes from a stack.


@@ -185,7 +204,7 @@ extern struct cds_lfs_node *__cds_lfs_pop(struct cds_lfs_stack *s);
  * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and
  *    __cds_lfs_pop_all(). (multi-provider/single-consumer scheme).
  */
  * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and
  *    __cds_lfs_pop_all(). (multi-provider/single-consumer scheme).
  */

-extern struct cds_lfs_head *__cds_lfs_pop_all(struct cds_lfs_stack *s);
+extern struct cds_lfs_head *__cds_lfs_pop_all(cds_lfs_stack_ptr_t s);

 
 #endif /* !_LGPL_SOURCE */
 
 
 #endif /* !_LGPL_SOURCE */