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87 lines
2.6 KiB
87 lines
2.6 KiB
/* |
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* RCU-based infrastructure for lightweight reader-writer locking |
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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) 2015, Red Hat, Inc. |
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* |
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* Author: Oleg Nesterov <[email protected]> |
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*/ |
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#ifndef _LINUX_RCU_SYNC_H_ |
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#define _LINUX_RCU_SYNC_H_ |
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#include <linux/wait.h> |
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#include <linux/rcupdate.h> |
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enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC }; |
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/* Structure to mediate between updaters and fastpath-using readers. */ |
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struct rcu_sync { |
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int gp_state; |
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int gp_count; |
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wait_queue_head_t gp_wait; |
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int cb_state; |
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struct rcu_head cb_head; |
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enum rcu_sync_type gp_type; |
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}; |
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extern void rcu_sync_lockdep_assert(struct rcu_sync *); |
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/** |
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* rcu_sync_is_idle() - Are readers permitted to use their fastpaths? |
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* @rsp: Pointer to rcu_sync structure to use for synchronization |
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* |
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* Returns true if readers are permitted to use their fastpaths. |
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* Must be invoked within an RCU read-side critical section whose |
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* flavor matches that of the rcu_sync struture. |
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*/ |
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static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) |
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{ |
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#ifdef CONFIG_PROVE_RCU |
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rcu_sync_lockdep_assert(rsp); |
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#endif |
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return !rsp->gp_state; /* GP_IDLE */ |
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} |
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extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); |
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extern void rcu_sync_enter_start(struct rcu_sync *); |
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extern void rcu_sync_enter(struct rcu_sync *); |
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extern void rcu_sync_exit(struct rcu_sync *); |
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extern void rcu_sync_dtor(struct rcu_sync *); |
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#define __RCU_SYNC_INITIALIZER(name, type) { \ |
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.gp_state = 0, \ |
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.gp_count = 0, \ |
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.gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ |
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.cb_state = 0, \ |
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.gp_type = type, \ |
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} |
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#define __DEFINE_RCU_SYNC(name, type) \ |
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struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) |
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#define DEFINE_RCU_SYNC(name) \ |
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__DEFINE_RCU_SYNC(name, RCU_SYNC) |
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#define DEFINE_RCU_SCHED_SYNC(name) \ |
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__DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) |
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#define DEFINE_RCU_BH_SYNC(name) \ |
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__DEFINE_RCU_SYNC(name, RCU_BH_SYNC) |
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#endif /* _LINUX_RCU_SYNC_H_ */
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