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Diffstat (limited to 'qemu/include/qemu/rcu_queue.h')
| -rw-r--r-- | qemu/include/qemu/rcu_queue.h | 134 |
1 files changed, 0 insertions, 134 deletions
diff --git a/qemu/include/qemu/rcu_queue.h b/qemu/include/qemu/rcu_queue.h deleted file mode 100644 index 3aca7a57e..000000000 --- a/qemu/include/qemu/rcu_queue.h +++ /dev/null @@ -1,134 +0,0 @@ -#ifndef QEMU_RCU_QUEUE_H -#define QEMU_RCU_QUEUE_H - -/* - * rcu_queue.h - * - * RCU-friendly versions of the queue.h primitives. - * - * 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 - * - * Copyright (c) 2013 Mike D. Day, IBM Corporation. - * - * IBM's contributions to this file may be relicensed under LGPLv2 or later. - */ - -#include "qemu/queue.h" -#include "qemu/atomic.h" - -#ifdef __cplusplus -extern "C" { -#endif - - -/* - * List access methods. - */ -#define QLIST_EMPTY_RCU(head) (atomic_rcu_read(&(head)->lh_first) == NULL) -#define QLIST_FIRST_RCU(head) (atomic_rcu_read(&(head)->lh_first)) -#define QLIST_NEXT_RCU(elm, field) (atomic_rcu_read(&(elm)->field.le_next)) - -/* - * List functions. - */ - - -/* - * The difference between atomic_read/set and atomic_rcu_read/set - * is in the including of a read/write memory barrier to the volatile - * access. atomic_rcu_* macros include the memory barrier, the - * plain atomic macros do not. Therefore, it should be correct to - * issue a series of reads or writes to the same element using only - * the atomic_* macro, until the last read or write, which should be - * atomic_rcu_* to introduce a read or write memory barrier as - * appropriate. - */ - -/* Upon publication of the listelm->next value, list readers - * will see the new node when following next pointers from - * antecedent nodes, but may not see the new node when following - * prev pointers from subsequent nodes until after the RCU grace - * period expires. - * see linux/include/rculist.h __list_add_rcu(new, prev, next) - */ -#define QLIST_INSERT_AFTER_RCU(listelm, elm, field) do { \ - (elm)->field.le_next = (listelm)->field.le_next; \ - (elm)->field.le_prev = &(listelm)->field.le_next; \ - atomic_rcu_set(&(listelm)->field.le_next, (elm)); \ - if ((elm)->field.le_next != NULL) { \ - (elm)->field.le_next->field.le_prev = \ - &(elm)->field.le_next; \ - } \ -} while (/*CONSTCOND*/0) - -/* Upon publication of the listelm->prev->next value, list - * readers will see the new element when following prev pointers - * from subsequent elements, but may not see the new element - * when following next pointers from antecedent elements - * until after the RCU grace period expires. - */ -#define QLIST_INSERT_BEFORE_RCU(listelm, elm, field) do { \ - (elm)->field.le_prev = (listelm)->field.le_prev; \ - (elm)->field.le_next = (listelm); \ - atomic_rcu_set((listelm)->field.le_prev, (elm)); \ - (listelm)->field.le_prev = &(elm)->field.le_next; \ -} while (/*CONSTCOND*/0) - -/* Upon publication of the head->first value, list readers - * will see the new element when following the head, but may - * not see the new element when following prev pointers from - * subsequent elements until after the RCU grace period has - * expired. - */ -#define QLIST_INSERT_HEAD_RCU(head, elm, field) do { \ - (elm)->field.le_prev = &(head)->lh_first; \ - (elm)->field.le_next = (head)->lh_first; \ - atomic_rcu_set((&(head)->lh_first), (elm)); \ - if ((elm)->field.le_next != NULL) { \ - (elm)->field.le_next->field.le_prev = \ - &(elm)->field.le_next; \ - } \ -} while (/*CONSTCOND*/0) - - -/* prior to publication of the elm->prev->next value, some list - * readers may still see the removed element when following - * the antecedent's next pointer. - */ -#define QLIST_REMOVE_RCU(elm, field) do { \ - if ((elm)->field.le_next != NULL) { \ - (elm)->field.le_next->field.le_prev = \ - (elm)->field.le_prev; \ - } \ - *(elm)->field.le_prev = (elm)->field.le_next; \ -} while (/*CONSTCOND*/0) - -/* List traversal must occur within an RCU critical section. */ -#define QLIST_FOREACH_RCU(var, head, field) \ - for ((var) = atomic_rcu_read(&(head)->lh_first); \ - (var); \ - (var) = atomic_rcu_read(&(var)->field.le_next)) - -/* List traversal must occur within an RCU critical section. */ -#define QLIST_FOREACH_SAFE_RCU(var, head, field, next_var) \ - for ((var) = (atomic_rcu_read(&(head)->lh_first)); \ - (var) && \ - ((next_var) = atomic_rcu_read(&(var)->field.le_next), 1); \ - (var) = (next_var)) - -#ifdef __cplusplus -} -#endif -#endif /* QEMU_RCU_QUEUE.H */ |