include/urcu/wfcqueue.h

   1 #ifndef _URCU_WFCQUEUE_H
   2 #define _URCU_WFCQUEUE_H
   3
   4 /*
   5  * urcu/wfcqueue.h
   6  *
   7  * Userspace RCU library - Concurrent Queue with Wait-Free Enqueue/Blocking Dequeue
   8  *
   9  * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  * Copyright 2011-2012 - Lai Jiangshan <laijs@cn.fujitsu.com>
  11  *
  12  * This library is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2.1 of the License, or (at your option) any later version.
  16  *
  17  * This library is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Lesser General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this library; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  25  */
  26
  27 #include <pthread.h>
  28 #include <stdbool.h>
  29 #include <urcu/compiler.h>
  30 #include <urcu/arch.h>
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 /*
  37  * Concurrent queue with wait-free enqueue/blocking dequeue.
  38  *
  39  * This queue has been designed and implemented collaboratively by
  40  * Mathieu Desnoyers and Lai Jiangshan. Inspired from
  41  * half-wait-free/half-blocking queue implementation done by Paul E.
  42  * McKenney.
  43  */
  44
  45 #define CDS_WFCQ_WOULDBLOCK     ((struct cds_wfcq_node *) -1UL)
  46
  47 enum cds_wfcq_ret {
  48         CDS_WFCQ_RET_WOULDBLOCK =       -1,
  49         CDS_WFCQ_RET_DEST_EMPTY =       0,
  50         CDS_WFCQ_RET_DEST_NON_EMPTY =   1,
  51         CDS_WFCQ_RET_SRC_EMPTY =        2,
  52 };
  53
  54 enum cds_wfcq_state {
  55         CDS_WFCQ_STATE_LAST =           (1U << 0),
  56 };
  57
  58 struct cds_wfcq_node {
  59         struct cds_wfcq_node *next;
  60 };
  61
  62 /*
  63  * Do not put head and tail on the same cache-line if concurrent
  64  * enqueue/dequeue are expected from many CPUs. This eliminates
  65  * false-sharing between enqueue and dequeue.
  66  */
  67 struct __cds_wfcq_head {
  68         struct cds_wfcq_node node;
  69 };
  70
  71 struct cds_wfcq_head {
  72         struct cds_wfcq_node node;
  73         pthread_mutex_t lock;
  74 };
  75
  76 /*
  77  * In C, the transparent union allows calling functions that work on both
  78  * struct cds_wfcq_head and struct __cds_wfcq_head on any of those two
  79  * types.
  80  *
  81  * In C++, implement static inline wrappers using function overloading
  82  * to obtain an API similar to C.
  83  *
  84  * Avoid complaints from clang++ not knowing the transparent union
  85  * attribute.
  86  */
  87 #if defined(__clang__)
  88 #pragma clang diagnostic push
  89 #pragma clang diagnostic ignored "-Wignored-attributes"
  90 #endif
  91 typedef union {
  92         struct __cds_wfcq_head *_h;
  93         struct cds_wfcq_head *h;
  94 } __attribute__((__transparent_union__)) cds_wfcq_head_ptr_t;
  95 #if defined(__clang__)
  96 #pragma clang diagnostic pop
  97 #endif
  98
  99 #ifndef __cplusplus
 100 /*
 101  * This static inline is only present for compatibility with C++. It is
 102  * effect-less in C.
 103  */
 104 static inline struct __cds_wfcq_head *__cds_wfcq_head_cast(struct __cds_wfcq_head *head)
 105 {
 106         return head;
 107 }
 108
 109 /*
 110  * This static inline is only present for compatibility with C++. It is
 111  * effect-less in C.
 112  */
 113 static inline struct cds_wfcq_head *cds_wfcq_head_cast(struct cds_wfcq_head *head)
 114 {
 115         return head;
 116 }
 117 #else /* #ifndef __cplusplus */
 118
 119 /*
 120  * This static inline is used by internally in the static inline
 121  * implementation of the API.
 122  */
 123 static inline cds_wfcq_head_ptr_t __cds_wfcq_head_cast(struct __cds_wfcq_head *head)
 124 {
 125         cds_wfcq_head_ptr_t ret = { ._h = head };
 126         return ret;
 127 }
 128
 129 /*
 130  * This static inline is used by internally in the static inline
 131  * implementation of the API.
 132  */
 133 static inline cds_wfcq_head_ptr_t cds_wfcq_head_cast(struct cds_wfcq_head *head)
 134 {
 135         cds_wfcq_head_ptr_t ret = { .h = head };
 136         return ret;
 137 }
 138 #endif /* #else #ifndef __cplusplus */
 139
 140 struct cds_wfcq_tail {
 141         struct cds_wfcq_node *p;
 142 };
 143
 144 #ifdef _LGPL_SOURCE
 145
 146 #include <urcu/static/wfcqueue.h>
 147
 148 #define cds_wfcq_node_init              _cds_wfcq_node_init
 149 #define cds_wfcq_init                   _cds_wfcq_init
 150 #define __cds_wfcq_init                 ___cds_wfcq_init
 151 #define cds_wfcq_destroy                _cds_wfcq_destroy
 152 #define cds_wfcq_empty                  _cds_wfcq_empty
 153 #define cds_wfcq_enqueue                _cds_wfcq_enqueue
 154
 155 /* Dequeue locking */
 156 #define cds_wfcq_dequeue_lock           _cds_wfcq_dequeue_lock
 157 #define cds_wfcq_dequeue_unlock         _cds_wfcq_dequeue_unlock
 158
 159 /* Locking performed within cds_wfcq calls. */
 160 #define cds_wfcq_dequeue_blocking       _cds_wfcq_dequeue_blocking
 161 #define cds_wfcq_dequeue_with_state_blocking    \
 162                                         _cds_wfcq_dequeue_with_state_blocking
 163 #define cds_wfcq_splice_blocking        _cds_wfcq_splice_blocking
 164 #define cds_wfcq_first_blocking         _cds_wfcq_first_blocking
 165 #define cds_wfcq_next_blocking          _cds_wfcq_next_blocking
 166
 167 /* Locking ensured by caller by holding cds_wfcq_dequeue_lock() */
 168 #define __cds_wfcq_dequeue_blocking     ___cds_wfcq_dequeue_blocking
 169 #define __cds_wfcq_dequeue_with_state_blocking  \
 170                                         ___cds_wfcq_dequeue_with_state_blocking
 171 #define __cds_wfcq_splice_blocking      ___cds_wfcq_splice_blocking
 172 #define __cds_wfcq_first_blocking       ___cds_wfcq_first_blocking
 173 #define __cds_wfcq_next_blocking        ___cds_wfcq_next_blocking
 174
 175 /*
 176  * Locking ensured by caller by holding cds_wfcq_dequeue_lock().
 177  * Non-blocking: deque, first, next return CDS_WFCQ_WOULDBLOCK if they
 178  * need to block. splice returns nonzero if it needs to block.
 179  */
 180 #define __cds_wfcq_dequeue_nonblocking  ___cds_wfcq_dequeue_nonblocking
 181 #define __cds_wfcq_dequeue_with_state_nonblocking       \
 182                                 ___cds_wfcq_dequeue_with_state_nonblocking
 183 #define __cds_wfcq_splice_nonblocking   ___cds_wfcq_splice_nonblocking
 184 #define __cds_wfcq_first_nonblocking    ___cds_wfcq_first_nonblocking
 185 #define __cds_wfcq_next_nonblocking     ___cds_wfcq_next_nonblocking
 186
 187 #else /* !_LGPL_SOURCE */
 188
 189 /*
 190  * Mutual exclusion of cds_wfcq_* / __cds_wfcq_* API
 191  *
 192  * Synchronization table:
 193  *
 194  * External synchronization techniques described in the API below is
 195  * required between pairs marked with "X". No external synchronization
 196  * required between pairs marked with "-".
 197  *
 198  * Legend:
 199  * [1] cds_wfcq_enqueue
 200  * [2] __cds_wfcq_splice (destination queue)
 201  * [3] __cds_wfcq_dequeue
 202  * [4] __cds_wfcq_splice (source queue)
 203  * [5] __cds_wfcq_first
 204  * [6] __cds_wfcq_next
 205  *
 206  *     [1] [2] [3] [4] [5] [6]
 207  * [1]  -   -   -   -   -   -
 208  * [2]  -   -   -   -   -   -
 209  * [3]  -   -   X   X   X   X
 210  * [4]  -   -   X   -   X   X
 211  * [5]  -   -   X   X   -   -
 212  * [6]  -   -   X   X   -   -
 213  *
 214  * Mutual exclusion can be ensured by holding cds_wfcq_dequeue_lock().
 215  *
 216  * For convenience, cds_wfcq_dequeue_blocking() and
 217  * cds_wfcq_splice_blocking() hold the dequeue lock.
 218  *
 219  * Besides locking, mutual exclusion of dequeue, splice and iteration
 220  * can be ensured by performing all of those operations from a single
 221  * thread, without requiring any lock.
 222  */
 223
 224 /*
 225  * cds_wfcq_node_init: initialize wait-free queue node.
 226  */
 227 extern void cds_wfcq_node_init(struct cds_wfcq_node *node);
 228
 229 /*
 230  * cds_wfcq_init: initialize wait-free queue. Pair with
 231  * cds_wfcq_destroy().
 232  */
 233 extern void cds_wfcq_init(struct cds_wfcq_head *head,
 234                 struct cds_wfcq_tail *tail);
 235
 236 /*
 237  * cds_wfcq_destroy: destroy wait-free queue. Pair with
 238  * cds_wfcq_init().
 239  */
 240 extern void cds_wfcq_destroy(struct cds_wfcq_head *head,
 241                 struct cds_wfcq_tail *tail);
 242
 243 /*
 244  * __cds_wfcq_init: initialize wait-free queue (without lock). Don't
 245  * pair with any destroy function.
 246  */
 247 extern void __cds_wfcq_init(struct __cds_wfcq_head *head,
 248                 struct cds_wfcq_tail *tail);
 249
 250 /*
 251  * cds_wfcq_empty: return whether wait-free queue is empty.
 252  *
 253  * No memory barrier is issued. No mutual exclusion is required.
 254  */
 255 extern bool cds_wfcq_empty(cds_wfcq_head_ptr_t head,
 256                 struct cds_wfcq_tail *tail);
 257
 258 /*
 259  * cds_wfcq_dequeue_lock: take the dequeue mutual exclusion lock.
 260  */
 261 extern void cds_wfcq_dequeue_lock(struct cds_wfcq_head *head,
 262                 struct cds_wfcq_tail *tail);
 263
 264 /*
 265  * cds_wfcq_dequeue_unlock: release the dequeue mutual exclusion lock.
 266  */
 267 extern void cds_wfcq_dequeue_unlock(struct cds_wfcq_head *head,
 268                 struct cds_wfcq_tail *tail);
 269
 270 /*
 271  * cds_wfcq_enqueue: enqueue a node into a wait-free queue.
 272  *
 273  * Issues a full memory barrier before enqueue. No mutual exclusion is
 274  * required.
 275  *
 276  * Returns false if the queue was empty prior to adding the node.
 277  * Returns true otherwise.
 278  */
 279 extern bool cds_wfcq_enqueue(cds_wfcq_head_ptr_t head,
 280                 struct cds_wfcq_tail *tail,
 281                 struct cds_wfcq_node *node);
 282
 283 /*
 284  * cds_wfcq_dequeue_blocking: dequeue a node from a wait-free queue.
 285  *
 286  * Content written into the node before enqueue is guaranteed to be
 287  * consistent, but no other memory ordering is ensured.
 288  * It is valid to reuse and free a dequeued node immediately.
 289  * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is
 290  * ensured.
 291  */
 292 extern struct cds_wfcq_node *cds_wfcq_dequeue_blocking(
 293                 struct cds_wfcq_head *head,
 294                 struct cds_wfcq_tail *tail);
 295
 296 /*
 297  * cds_wfcq_dequeue_with_state_blocking: dequeue with state.
 298  *
 299  * Same as cds_wfcq_dequeue_blocking, but saves whether dequeueing the
 300  * last node of the queue into state (CDS_WFCQ_STATE_LAST).
 301  */
 302 extern struct cds_wfcq_node *cds_wfcq_dequeue_with_state_blocking(
 303                 struct cds_wfcq_head *head,
 304                 struct cds_wfcq_tail *tail,
 305                 int *state);
 306
 307 /*
 308  * cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
 309  *
 310  * Dequeue all nodes from src_q.
 311  * dest_q must be already initialized.
 312  * Content written into the node before enqueue is guaranteed to be
 313  * consistent, but no other memory ordering is ensured.
 314  * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is
 315  * ensured.
 316  *
 317  * Returns enum cds_wfcq_ret which indicates the state of the src or
 318  * dest queue.
 319  */
 320 extern enum cds_wfcq_ret cds_wfcq_splice_blocking(
 321                 struct cds_wfcq_head *dest_q_head,
 322                 struct cds_wfcq_tail *dest_q_tail,
 323                 struct cds_wfcq_head *src_q_head,
 324                 struct cds_wfcq_tail *src_q_tail);
 325
 326 /*
 327  * __cds_wfcq_dequeue_blocking: dequeue a node from a wait-free queue.
 328  *
 329  * Content written into the node before enqueue is guaranteed to be
 330  * consistent, but no other memory ordering is ensured.
 331  * It is valid to reuse and free a dequeued node immediately.
 332  * Dequeue/splice/iteration mutual exclusion should be ensured by the
 333  * caller.
 334  */
 335 extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking(
 336                 cds_wfcq_head_ptr_t head,
 337                 struct cds_wfcq_tail *tail);
 338
 339 /*
 340  * __cds_wfcq_dequeue_with_state_blocking: dequeue with state.
 341  *
 342  * Same as __cds_wfcq_dequeue_blocking, but saves whether dequeueing the
 343  * last node of the queue into state (CDS_WFCQ_STATE_LAST).
 344  */
 345 extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking(
 346                 cds_wfcq_head_ptr_t head,
 347                 struct cds_wfcq_tail *tail,
 348                 int *state);
 349
 350 /*
 351  * __cds_wfcq_dequeue_nonblocking: dequeue a node from a wait-free queue.
 352  *
 353  * Same as __cds_wfcq_dequeue_blocking, but returns CDS_WFCQ_WOULDBLOCK
 354  * if it needs to block.
 355  */
 356 extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking(
 357                 cds_wfcq_head_ptr_t head,
 358                 struct cds_wfcq_tail *tail);
 359
 360 /*
 361  * __cds_wfcq_dequeue_with_state_blocking: dequeue with state.
 362  *
 363  * Same as __cds_wfcq_dequeue_nonblocking, but saves whether dequeueing
 364  * the last node of the queue into state (CDS_WFCQ_STATE_LAST).
 365  */
 366 extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking(
 367                 cds_wfcq_head_ptr_t head,
 368                 struct cds_wfcq_tail *tail,
 369                 int *state);
 370
 371 /*
 372  * __cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
 373  *
 374  * Dequeue all nodes from src_q.
 375  * dest_q must be already initialized.
 376  * Mutual exclusion for src_q should be ensured by the caller as
 377  * specified in the "Synchronisation table".
 378  * Returns enum cds_wfcq_ret which indicates the state of the src or
 379  * dest queue. Never returns CDS_WFCQ_RET_WOULDBLOCK.
 380  */
 381 extern enum cds_wfcq_ret __cds_wfcq_splice_blocking(
 382                 cds_wfcq_head_ptr_t dest_q_head,
 383                 struct cds_wfcq_tail *dest_q_tail,
 384                 cds_wfcq_head_ptr_t src_q_head,
 385                 struct cds_wfcq_tail *src_q_tail);
 386
 387 /*
 388  * __cds_wfcq_splice_nonblocking: enqueue all src_q nodes at the end of dest_q.
 389  *
 390  * Same as __cds_wfcq_splice_blocking, but returns
 391  * CDS_WFCQ_RET_WOULDBLOCK if it needs to block.
 392  */
 393 extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking(
 394                 cds_wfcq_head_ptr_t dest_q_head,
 395                 struct cds_wfcq_tail *dest_q_tail,
 396                 cds_wfcq_head_ptr_t src_q_head,
 397                 struct cds_wfcq_tail *src_q_tail);
 398
 399 /*
 400  * __cds_wfcq_first_blocking: get first node of a queue, without dequeuing.
 401  *
 402  * Content written into the node before enqueue is guaranteed to be
 403  * consistent, but no other memory ordering is ensured.
 404  * Dequeue/splice/iteration mutual exclusion should be ensured by the
 405  * caller.
 406  *
 407  * Used by for-like iteration macros:
 408  * __cds_wfcq_for_each_blocking()
 409  * __cds_wfcq_for_each_blocking_safe()
 410  *
 411  * Returns NULL if queue is empty, first node otherwise.
 412  */
 413 extern struct cds_wfcq_node *__cds_wfcq_first_blocking(
 414                 cds_wfcq_head_ptr_t head,
 415                 struct cds_wfcq_tail *tail);
 416
 417 /*
 418  * __cds_wfcq_first_nonblocking: get first node of a queue, without dequeuing.
 419  *
 420  * Same as __cds_wfcq_first_blocking, but returns CDS_WFCQ_WOULDBLOCK if
 421  * it needs to block.
 422  */
 423 extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking(
 424                 cds_wfcq_head_ptr_t head,
 425                 struct cds_wfcq_tail *tail);
 426
 427 /*
 428  * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing.
 429  *
 430  * Content written into the node before enqueue is guaranteed to be
 431  * consistent, but no other memory ordering is ensured.
 432  * Dequeue/splice/iteration mutual exclusion should be ensured by the
 433  * caller.
 434  *
 435  * Used by for-like iteration macros:
 436  * __cds_wfcq_for_each_blocking()
 437  * __cds_wfcq_for_each_blocking_safe()
 438  *
 439  * Returns NULL if reached end of queue, non-NULL next queue node
 440  * otherwise.
 441  */
 442 extern struct cds_wfcq_node *__cds_wfcq_next_blocking(
 443                 cds_wfcq_head_ptr_t head,
 444                 struct cds_wfcq_tail *tail,
 445                 struct cds_wfcq_node *node);
 446
 447 /*
 448  * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing.
 449  *
 450  * Same as __cds_wfcq_next_blocking, but returns CDS_WFCQ_WOULDBLOCK if
 451  * it needs to block.
 452  */
 453 extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking(
 454                 cds_wfcq_head_ptr_t head,
 455                 struct cds_wfcq_tail *tail,
 456                 struct cds_wfcq_node *node);
 457
 458 #endif /* !_LGPL_SOURCE */
 459
 460 /*
 461  * __cds_wfcq_for_each_blocking: Iterate over all nodes in a queue,
 462  * without dequeuing them.
 463  * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer).
 464  * @tail: tail of the queue (struct cds_wfcq_tail pointer).
 465  * @node: iterator on the queue (struct cds_wfcq_node pointer).
 466  *
 467  * Content written into each node before enqueue is guaranteed to be
 468  * consistent, but no other memory ordering is ensured.
 469  * Dequeue/splice/iteration mutual exclusion should be ensured by the
 470  * caller.
 471  */
 472 #define __cds_wfcq_for_each_blocking(head, tail, node)          \
 473         for (node = __cds_wfcq_first_blocking(head, tail);      \
 474                 node != NULL;                                   \
 475                 node = __cds_wfcq_next_blocking(head, tail, node))
 476
 477 /*
 478  * __cds_wfcq_for_each_blocking_safe: Iterate over all nodes in a queue,
 479  * without dequeuing them. Safe against deletion.
 480  * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer).
 481  * @tail: tail of the queue (struct cds_wfcq_tail pointer).
 482  * @node: iterator on the queue (struct cds_wfcq_node pointer).
 483  * @n: struct cds_wfcq_node pointer holding the next pointer (used
 484  *     internally).
 485  *
 486  * Content written into each node before enqueue is guaranteed to be
 487  * consistent, but no other memory ordering is ensured.
 488  * Dequeue/splice/iteration mutual exclusion should be ensured by the
 489  * caller.
 490  */
 491 #define __cds_wfcq_for_each_blocking_safe(head, tail, node, n)                 \
 492         for (node = __cds_wfcq_first_blocking(head, tail),                     \
 493                         n = (node ? __cds_wfcq_next_blocking(head, tail, node) : NULL); \
 494                 node != NULL;                                                  \
 495                 node = n, n = (node ? __cds_wfcq_next_blocking(head, tail, node) : NULL))
 496
 497 #ifdef __cplusplus
 498 }
 499
 500 /*
 501  * In C++, implement static inline wrappers using function overloading
 502  * to obtain an API similar to C.
 503  */
 504
 505 static inline cds_wfcq_head_ptr_t cds_wfcq_head_cast_cpp(struct __cds_wfcq_head *head)
 506 {
 507         cds_wfcq_head_ptr_t ret = { ._h = head };
 508         return ret;
 509 }
 510
 511 static inline cds_wfcq_head_ptr_t cds_wfcq_head_cast_cpp(struct cds_wfcq_head *head)
 512 {
 513         cds_wfcq_head_ptr_t ret = { .h = head };
 514         return ret;
 515 }
 516
 517 template<typename T> static inline bool cds_wfcq_empty(T head,
 518                 struct cds_wfcq_tail *tail)
 519 {
 520         return cds_wfcq_empty(cds_wfcq_head_cast_cpp(head), tail);
 521 }
 522
 523 template<typename T> static inline bool cds_wfcq_enqueue(T head,
 524                 struct cds_wfcq_tail *tail,
 525                 struct cds_wfcq_node *node)
 526 {
 527         return cds_wfcq_enqueue(cds_wfcq_head_cast_cpp(head), tail, node);
 528 }
 529
 530 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_dequeue_blocking(
 531                 T head, struct cds_wfcq_tail *tail)
 532 {
 533         return __cds_wfcq_dequeue_blocking(cds_wfcq_head_cast_cpp(head), tail);
 534 }
 535
 536 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking(
 537                 T head, struct cds_wfcq_tail *tail, int *state)
 538 {
 539         return __cds_wfcq_dequeue_with_state_blocking(cds_wfcq_head_cast_cpp(head),
 540                         tail, state);
 541 }
 542
 543 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking(
 544                 T head, struct cds_wfcq_tail *tail)
 545 {
 546         return __cds_wfcq_dequeue_nonblocking(cds_wfcq_head_cast_cpp(head), tail);
 547 }
 548
 549 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking(
 550                 T head, struct cds_wfcq_tail *tail, int *state)
 551 {
 552         return __cds_wfcq_dequeue_with_state_nonblocking(cds_wfcq_head_cast_cpp(head),
 553                         tail, state);
 554 }
 555
 556 template<typename T, typename U> static inline enum cds_wfcq_ret __cds_wfcq_splice_blocking(
 557                 T dest_q_head,
 558                 struct cds_wfcq_tail *dest_q_tail,
 559                 U src_q_head,
 560                 struct cds_wfcq_tail *src_q_tail)
 561 {
 562         return __cds_wfcq_splice_blocking(cds_wfcq_head_cast_cpp(dest_q_head),
 563                         dest_q_tail,
 564                         cds_wfcq_head_cast_cpp(src_q_head),
 565                         src_q_tail);
 566 }
 567
 568 template<typename T, typename U> static inline enum cds_wfcq_ret __cds_wfcq_splice_nonblocking(
 569                 T dest_q_head,
 570                 struct cds_wfcq_tail *dest_q_tail,
 571                 U *src_q_head,
 572                 struct cds_wfcq_tail *src_q_tail)
 573 {
 574         return __cds_wfcq_splice_nonblocking(cds_wfcq_head_cast_cpp(dest_q_head),
 575                         dest_q_tail,
 576                         cds_wfcq_head_cast_cpp(src_q_head),
 577                         src_q_tail);
 578 }
 579
 580 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_first_blocking(
 581                 T head, struct cds_wfcq_tail *tail)
 582 {
 583         return __cds_wfcq_first_blocking(cds_wfcq_head_cast_cpp(head), tail);
 584 }
 585
 586 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_first_nonblocking(
 587                 T head, struct cds_wfcq_tail *tail)
 588 {
 589         return __cds_wfcq_first_nonblocking(cds_wfcq_head_cast_cpp(head), tail);
 590 }
 591
 592 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_next_blocking(
 593                 T head,
 594                 struct cds_wfcq_tail *tail,
 595                 struct cds_wfcq_node *node)
 596 {
 597         return __cds_wfcq_next_blocking(cds_wfcq_head_cast_cpp(head), tail, node);
 598 }
 599
 600 template<typename T> static inline struct cds_wfcq_node *__cds_wfcq_next_nonblocking(
 601                 T head,
 602                 struct cds_wfcq_tail *tail,
 603                 struct cds_wfcq_node *node)
 604 {
 605         return __cds_wfcq_next_nonblocking(cds_wfcq_head_cast_cpp(head), tail, node);
 606 }
 607
 608 #endif
 609
 610 #endif /* _URCU_WFCQUEUE_H */