-#ifndef _URCU_QSBR_STATIC_H
-#define _URCU_QSBR_STATIC_H
-
-/*
- * urcu-qsbr-static.h
- *
- * Userspace RCU QSBR header.
- *
- * TO BE INCLUDED ONLY IN CODE THAT IS TO BE RECOMPILED ON EACH LIBURCU
- * RELEASE. See urcu.h for linking dynamically with the userspace rcu library.
- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
- *
- * 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
- *
- * IBM's contributions to this file may be relicensed under LGPLv2 or later.
- */
-
-#include <stdlib.h>
-#include <pthread.h>
-#include <limits.h>
-#include <unistd.h>
-#include <stdint.h>
-
-#include <urcu/compiler.h>
-#include <urcu/arch.h>
-#include <urcu/system.h>
-#include <urcu/uatomic.h>
-#include <urcu/list.h>
-#include <urcu/futex.h>
-#include <urcu/tls-compat.h>
-#include <urcu/debug.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/*
- * This code section can only be included in LGPL 2.1 compatible source code.
- * See below for the function call wrappers which can be used in code meant to
- * be only linked with the Userspace RCU library. This comes with a small
- * performance degradation on the read-side due to the added function calls.
- * This is required to permit relinking with newer versions of the library.
- */
-
-enum rcu_state {
- RCU_READER_ACTIVE_CURRENT,
- RCU_READER_ACTIVE_OLD,
- RCU_READER_INACTIVE,
-};
-
-#define RCU_GP_ONLINE (1UL << 0)
-#define RCU_GP_CTR (1UL << 1)
-
-struct rcu_gp {
- /*
- * Global quiescent period counter with low-order bits unused.
- * Using a int rather than a char to eliminate false register
- * dependencies causing stalls on some architectures.
- */
- unsigned long ctr;
-
- int32_t futex;
-} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
-
-extern struct rcu_gp rcu_gp;
-
-struct rcu_reader {
- /* Data used by both reader and synchronize_rcu() */
- unsigned long ctr;
- /* Data used for registry */
- struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
- int waiting;
- pthread_t tid;
- /* Reader registered flag, for internal checks. */
- unsigned int registered:1;
-};
-
-extern DECLARE_URCU_TLS(struct rcu_reader, rcu_reader);
-
-/*
- * Wake-up waiting synchronize_rcu(). Called from many concurrent threads.
- */
-static inline void wake_up_gp(void)
-{
- if (caa_unlikely(_CMM_LOAD_SHARED(URCU_TLS(rcu_reader).waiting))) {
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader).waiting, 0);
- cmm_smp_mb();
- if (uatomic_read(&rcu_gp.futex) != -1)
- return;
- uatomic_set(&rcu_gp.futex, 0);
- /*
- * Ignoring return value until we can make this function
- * return something (because urcu_die() is not publicly
- * exposed).
- */
- (void) futex_noasync(&rcu_gp.futex, FUTEX_WAKE, 1,
- NULL, NULL, 0);
- }
-}
-
-static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
-{
- unsigned long v;
-
- v = CMM_LOAD_SHARED(*ctr);
- if (!v)
- return RCU_READER_INACTIVE;
- if (v == rcu_gp.ctr)
- return RCU_READER_ACTIVE_CURRENT;
- return RCU_READER_ACTIVE_OLD;
-}
-
-/*
- * Enter an RCU read-side critical section.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline void _rcu_read_lock(void)
-{
- urcu_assert(URCU_TLS(rcu_reader).ctr);
-}
-
-/*
- * Exit an RCU read-side critical section.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline void _rcu_read_unlock(void)
-{
- urcu_assert(URCU_TLS(rcu_reader).ctr);
-}
-
-/*
- * Returns whether within a RCU read-side critical section.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline int _rcu_read_ongoing(void)
-{
- return URCU_TLS(rcu_reader).ctr;
-}
-
-/*
- * This is a helper function for _rcu_quiescent_state().
- * The first cmm_smp_mb() ensures memory accesses in the prior read-side
- * critical sections are not reordered with store to
- * URCU_TLS(rcu_reader).ctr, and ensures that mutexes held within an
- * offline section that would happen to end with this
- * rcu_quiescent_state() call are not reordered with
- * store to URCU_TLS(rcu_reader).ctr.
- */
-static inline void _rcu_quiescent_state_update_and_wakeup(unsigned long gp_ctr)
-{
- cmm_smp_mb();
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, gp_ctr);
- cmm_smp_mb(); /* write URCU_TLS(rcu_reader).ctr before read futex */
- wake_up_gp();
- cmm_smp_mb();
-}
-
-/*
- * Inform RCU of a quiescent state.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- *
- * We skip the memory barriers and gp store if our local ctr already
- * matches the global rcu_gp.ctr value: this is OK because a prior
- * _rcu_quiescent_state() or _rcu_thread_online() already updated it
- * within our thread, so we have no quiescent state to report.
- */
-static inline void _rcu_quiescent_state(void)
-{
- unsigned long gp_ctr;
-
- urcu_assert(URCU_TLS(rcu_reader).registered);
- if ((gp_ctr = CMM_LOAD_SHARED(rcu_gp.ctr)) == URCU_TLS(rcu_reader).ctr)
- return;
- _rcu_quiescent_state_update_and_wakeup(gp_ctr);
-}
-
-/*
- * Take a thread offline, prohibiting it from entering further RCU
- * read-side critical sections.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline void _rcu_thread_offline(void)
-{
- urcu_assert(URCU_TLS(rcu_reader).registered);
- cmm_smp_mb();
- CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, 0);
- cmm_smp_mb(); /* write URCU_TLS(rcu_reader).ctr before read futex */
- wake_up_gp();
- cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
-}
-
-/*
- * Bring a thread online, allowing it to once again enter RCU
- * read-side critical sections.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline void _rcu_thread_online(void)
-{
- urcu_assert(URCU_TLS(rcu_reader).registered);
- cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, CMM_LOAD_SHARED(rcu_gp.ctr));
- cmm_smp_mb();
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* _URCU_QSBR_STATIC_H */
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