94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/*
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* Sleepable Read-Copy Update mechanism for mutual exclusion,
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* tiny variant.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you can access it online at
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* http://www.gnu.org/licenses/gpl-2.0.html.
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*
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* Copyright (C) IBM Corporation, 2017
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*
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* Author: Paul McKenney <paulmck@us.ibm.com>
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*/
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#ifndef _LINUX_SRCU_TINY_H
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#define _LINUX_SRCU_TINY_H
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#include <linux/swait.h>
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struct srcu_struct {
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int srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */
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struct swait_queue_head srcu_wq;
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/* Last srcu_read_unlock() wakes GP. */
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unsigned long srcu_gp_seq; /* GP seq # for callback tagging. */
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struct rcu_segcblist srcu_cblist;
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/* Pending SRCU callbacks. */
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int srcu_idx; /* Current reader array element. */
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bool srcu_gp_running; /* GP workqueue running? */
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bool srcu_gp_waiting; /* GP waiting for readers? */
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struct work_struct srcu_work; /* For driving grace periods. */
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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};
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void srcu_drive_gp(struct work_struct *wp);
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#define __SRCU_STRUCT_INIT(name) \
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{ \
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.srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq), \
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.srcu_cblist = RCU_SEGCBLIST_INITIALIZER(name.srcu_cblist), \
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.srcu_work = __WORK_INITIALIZER(name.srcu_work, srcu_drive_gp), \
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__SRCU_DEP_MAP_INIT(name) \
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}
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/*
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* This odd _STATIC_ arrangement is needed for API compatibility with
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* Tree SRCU, which needs some per-CPU data.
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*/
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#define DEFINE_SRCU(name) \
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struct srcu_struct name = __SRCU_STRUCT_INIT(name)
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#define DEFINE_STATIC_SRCU(name) \
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static struct srcu_struct name = __SRCU_STRUCT_INIT(name)
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void synchronize_srcu(struct srcu_struct *sp);
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static inline void synchronize_srcu_expedited(struct srcu_struct *sp)
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{
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synchronize_srcu(sp);
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}
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static inline void srcu_barrier(struct srcu_struct *sp)
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{
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synchronize_srcu(sp);
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}
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static inline unsigned long srcu_batches_completed(struct srcu_struct *sp)
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{
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return 0;
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}
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static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
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struct srcu_struct *sp, int *flags,
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unsigned long *gpnum,
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unsigned long *completed)
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{
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if (test_type != SRCU_FLAVOR)
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return;
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*flags = 0;
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*completed = sp->srcu_gp_seq;
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*gpnum = *completed;
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}
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#endif
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