--- /dev/null
+#ifndef _URCU_BP_STATIC_H
+#define _URCU_BP_STATIC_H
+
+/*
+ * urcu-bp-static.h
+ *
+ * Userspace RCU header.
+ *
+ * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu.h for linking
+ * dynamically with the userspace rcu library.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * 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 <syscall.h>
+#include <unistd.h>
+
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu/system.h>
+#include <urcu/arch_uatomic.h>
+#include <urcu/list.h>
+
+/*
+ * 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.
+ */
+
+/*
+ * Active attempts to check for reader Q.S. before calling sleep().
+ */
+#define RCU_QS_ACTIVE_ATTEMPTS 100
+
+#ifdef DEBUG_RCU
+#define rcu_assert(args...) assert(args)
+#else
+#define rcu_assert(args...)
+#endif
+
+#ifdef DEBUG_YIELD
+#include <sched.h>
+#include <time.h>
+#include <pthread.h>
+#include <unistd.h>
+
+#define YIELD_READ (1 << 0)
+#define YIELD_WRITE (1 << 1)
+
+/*
+ * Updates without URCU_MB are much slower. Account this in
+ * the delay.
+ */
+/* maximum sleep delay, in us */
+#define MAX_SLEEP 50
+
+extern unsigned int yield_active;
+extern unsigned int __thread rand_yield;
+
+static inline void debug_yield_read(void)
+{
+ if (yield_active & YIELD_READ)
+ if (rand_r(&rand_yield) & 0x1)
+ usleep(rand_r(&rand_yield) % MAX_SLEEP);
+}
+
+static inline void debug_yield_write(void)
+{
+ if (yield_active & YIELD_WRITE)
+ if (rand_r(&rand_yield) & 0x1)
+ usleep(rand_r(&rand_yield) % MAX_SLEEP);
+}
+
+static inline void debug_yield_init(void)
+{
+ rand_yield = time(NULL) ^ pthread_self();
+}
+#else
+static inline void debug_yield_read(void)
+{
+}
+
+static inline void debug_yield_write(void)
+{
+}
+
+static inline void debug_yield_init(void)
+{
+
+}
+#endif
+
+/*
+ * The trick here is that RCU_GP_CTR_BIT must be a multiple of 8 so we can use a
+ * full 8-bits, 16-bits or 32-bits bitmask for the lower order bits.
+ */
+#define RCU_GP_COUNT (1UL << 0)
+/* Use the amount of bits equal to half of the architecture long size */
+#define RCU_GP_CTR_BIT (1UL << (sizeof(long) << 2))
+#define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_BIT - 1)
+
+/*
+ * Used internally by _rcu_read_lock.
+ */
+extern void rcu_bp_register(void);
+
+/*
+ * 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.
+ */
+extern long urcu_gp_ctr;
+
+struct urcu_reader {
+ /* Data used by both reader and synchronize_rcu() */
+ long ctr;
+ /* Data used for registry */
+ struct list_head head __attribute__((aligned(CACHE_LINE_SIZE)));
+ pthread_t tid;
+ int alloc; /* registry entry allocated */
+};
+
+/*
+ * Bulletproof version keeps a pointer to a registry not part of the TLS.
+ * Adds a pointer dereference on the read-side, but won't require to unregister
+ * the reader thread.
+ */
+extern struct urcu_reader __thread *urcu_reader;
+
+static inline int rcu_old_gp_ongoing(long *value)
+{
+ long v;
+
+ if (value == NULL)
+ return 0;
+ /*
+ * Make sure both tests below are done on the same version of *value
+ * to insure consistency.
+ */
+ v = LOAD_SHARED(*value);
+ return (v & RCU_GP_CTR_NEST_MASK) &&
+ ((v ^ urcu_gp_ctr) & RCU_GP_CTR_BIT);
+}
+
+static inline void _rcu_read_lock(void)
+{
+ long tmp;
+
+ /* Check if registered */
+ if (unlikely(!urcu_reader))
+ rcu_bp_register();
+
+ tmp = urcu_reader->ctr;
+ /* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
+ if (likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
+ _STORE_SHARED(urcu_reader->ctr, _LOAD_SHARED(urcu_gp_ctr));
+ /*
+ * Set active readers count for outermost nesting level before
+ * accessing the pointer.
+ */
+ smp_mb();
+ } else {
+ _STORE_SHARED(urcu_reader->ctr, tmp + RCU_GP_COUNT);
+ }
+}
+
+static inline void _rcu_read_unlock(void)
+{
+ /*
+ * Finish using rcu before decrementing the pointer.
+ */
+ smp_mb();
+ _STORE_SHARED(urcu_reader->ctr, urcu_reader->ctr - RCU_GP_COUNT);
+}
+
+#endif /* _URCU_BP_STATIC_H */
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