X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fwfstack.h;h=9d693053117ceb93e69034e433f2196a22c3070d;hp=b6992e888cfa71f2334c485034c11f7a788b9fac;hb=2af1c19e6a553878fcb2a5106f050d5ed7ac0f54;hpb=edac6b69ad8b690437c4624cebb7eef465a09a7e diff --git a/urcu/wfstack.h b/urcu/wfstack.h index b6992e8..9d69305 100644 --- a/urcu/wfstack.h +++ b/urcu/wfstack.h @@ -6,7 +6,7 @@ * * Userspace RCU library - Stack with wait-free push, blocking traversal. * - * Copyright 2010 - Mathieu Desnoyers + * Copyright 2010-2012 - Mathieu Desnoyers * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -38,9 +38,10 @@ extern "C" { * 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. - * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, iteration on 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: * @@ -57,6 +58,12 @@ extern "C" { * 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 @@ -76,30 +83,48 @@ 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 #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_blocking _cds_wfs_first_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 @@ -107,6 +132,11 @@ struct cds_wfs_stack { /* 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 */ @@ -117,16 +147,29 @@ struct cds_wfs_stack { extern void cds_wfs_node_init(struct cds_wfs_node *node); /* - * cds_wfs_init: initialize wait-free stack. + * 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(struct cds_wfs_stack *s); +extern bool cds_wfs_empty(cds_wfs_stack_ptr_t u_stack); /* * cds_wfs_push: push a node into the stack. @@ -137,7 +180,7 @@ extern bool cds_wfs_empty(struct cds_wfs_stack *s); * Returns 0 if the stack was empty prior to adding the node. * Returns non-zero otherwise. */ -extern int cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node); +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. @@ -146,6 +189,15 @@ extern int cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node); */ 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. * @@ -154,7 +206,7 @@ extern struct cds_wfs_node *cds_wfs_pop_blocking(struct cds_wfs_stack *s); extern struct cds_wfs_head *cds_wfs_pop_all_blocking(struct cds_wfs_stack *s); /* - * cds_wfs_first_blocking: get first node of a popped stack. + * 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. @@ -162,8 +214,10 @@ extern struct cds_wfs_head *cds_wfs_pop_all_blocking(struct cds_wfs_stack *s); * 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_blocking(struct cds_wfs_head *head); +extern struct cds_wfs_node *cds_wfs_first(struct cds_wfs_head *head); /* * cds_wfs_next_blocking: get next node of a popped stack. @@ -174,9 +228,20 @@ extern struct cds_wfs_node *cds_wfs_first_blocking(struct cds_wfs_head *head); * 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. */ @@ -203,7 +268,35 @@ extern void cds_wfs_pop_unlock(struct cds_wfs_stack *s); * 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(struct cds_wfs_stack *s); +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. @@ -222,7 +315,7 @@ extern struct cds_wfs_node *__cds_wfs_pop_blocking(struct cds_wfs_stack *s); * 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(struct cds_wfs_stack *s); +extern struct cds_wfs_head *__cds_wfs_pop_all(cds_wfs_stack_ptr_t u_stack); #endif /* !_LGPL_SOURCE */ @@ -240,7 +333,7 @@ extern struct cds_wfs_head *__cds_wfs_pop_all(struct cds_wfs_stack *s); * consistent, but no other memory ordering is ensured. */ #define cds_wfs_for_each_blocking(head, node) \ - for (node = cds_wfs_first_blocking(head); \ + for (node = cds_wfs_first(head); \ node != NULL; \ node = cds_wfs_next_blocking(node)) @@ -256,7 +349,7 @@ extern struct cds_wfs_head *__cds_wfs_pop_all(struct cds_wfs_stack *s); * consistent, but no other memory ordering is ensured. */ #define cds_wfs_for_each_blocking_safe(head, node, n) \ - for (node = cds_wfs_first_blocking(head), \ + 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))