1 files changed, 120 insertions, 0 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
new file mode 100644
index 000000000..5efb51486
--- /dev/null
+++ b/include/linux/rcutree.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ *
+ * Copyright IBM Corporation, 2008
+ *
+ * Author: Dipankar Sarma <dipankar@in.ibm.com>
+ *	   Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical algorithm
+ *
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
+ * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *	Documentation/RCU
+ */
+
+#ifndef __LINUX_RCUTREE_H
+#define __LINUX_RCUTREE_H
+
+void rcu_softirq_qs(void);
+void rcu_note_context_switch(bool preempt);
+int rcu_needs_cpu(void);
+void rcu_cpu_stall_reset(void);
+
+/*
+ * Note a virtualization-based context switch.  This is simply a
+ * wrapper around rcu_note_context_switch(), which allows TINY_RCU
+ * to save a few bytes. The caller must have disabled interrupts.
+ */
+static inline void rcu_virt_note_context_switch(int cpu)
+{
+	rcu_note_context_switch(false);
+}
+
+void synchronize_rcu_expedited(void);
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
+
+void rcu_barrier(void);
+bool rcu_eqs_special_set(int cpu);
+void rcu_momentary_dyntick_idle(void);
+void kfree_rcu_scheduler_running(void);
+bool rcu_gp_might_be_stalled(void);
+
+struct rcu_gp_oldstate {
+	unsigned long rgos_norm;
+	unsigned long rgos_exp;
+};
+
+// Maximum number of rcu_gp_oldstate values corresponding to
+// not-yet-completed RCU grace periods.
+#define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4
+
+/**
+ * same_state_synchronize_rcu_full - Are two old-state values identical?
+ * @rgosp1: First old-state value.
+ * @rgosp2: Second old-state value.
+ *
+ * The two old-state values must have been obtained from either
+ * get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(),
+ * or get_completed_synchronize_rcu_full().  Returns @true if the two
+ * values are identical and @false otherwise.  This allows structures
+ * whose lifetimes are tracked by old-state values to push these values
+ * to a list header, allowing those structures to be slightly smaller.
+ *
+ * Note that equality is judged on a bitwise basis, so that an
+ * @rcu_gp_oldstate structure with an already-completed state in one field
+ * will compare not-equal to a structure with an already-completed state
+ * in the other field.  After all, the @rcu_gp_oldstate structure is opaque
+ * so how did such a situation come to pass in the first place?
+ */
+static inline bool same_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp1,
+						   struct rcu_gp_oldstate *rgosp2)
+{
+	return rgosp1->rgos_norm == rgosp2->rgos_norm && rgosp1->rgos_exp == rgosp2->rgos_exp;
+}
+
+unsigned long start_poll_synchronize_rcu_expedited(void);
+void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
+void cond_synchronize_rcu_expedited(unsigned long oldstate);
+void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
+unsigned long get_state_synchronize_rcu(void);
+void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
+unsigned long start_poll_synchronize_rcu(void);
+void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
+bool poll_state_synchronize_rcu(unsigned long oldstate);
+bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
+void cond_synchronize_rcu(unsigned long oldstate);
+void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
+
+bool rcu_is_idle_cpu(int cpu);
+
+#ifdef CONFIG_PROVE_RCU
+void rcu_irq_exit_check_preempt(void);
+#else
+static inline void rcu_irq_exit_check_preempt(void) { }
+#endif
+
+struct task_struct;
+void rcu_preempt_deferred_qs(struct task_struct *t);
+
+void exit_rcu(void);
+
+void rcu_scheduler_starting(void);
+extern int rcu_scheduler_active;
+void rcu_end_inkernel_boot(void);
+bool rcu_inkernel_boot_has_ended(void);
+bool rcu_is_watching(void);
+#ifndef CONFIG_PREEMPTION
+void rcu_all_qs(void);
+#endif
+
+/* RCUtree hotplug events */
+int rcutree_prepare_cpu(unsigned int cpu);
+int rcutree_online_cpu(unsigned int cpu);
+int rcutree_offline_cpu(unsigned int cpu);
+int rcutree_dead_cpu(unsigned int cpu);
+int rcutree_dying_cpu(unsigned int cpu);
+void rcu_cpu_starting(unsigned int cpu);
+
+#endif /* __LINUX_RCUTREE_H */