rcu: Remove "extern" from function declarations in include/linux/*rcu*.h

Function prototypes don't need to have the "extern" keyword since this
is the default behavior. Its explicit use is redundant. This commit
therefore removes them.

Signed-off-by: Teodora Baluta <[e-mail]>
Signed-off-by: Paul E. McKenney <[e-mail]>

include/linux/rculist.h

···
 	next->prev = new;
 }
 #else
-extern void __list_add_rcu(struct list_head *new,
-		struct list_head *prev, struct list_head *next);
+void __list_add_rcu(struct list_head *new,
+		    struct list_head *prev, struct list_head *next);
 #endif
 
 /**

include/linux/rcupdate.h

···
 #endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
 
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
-extern void rcutorture_record_test_transition(void);
-extern void rcutorture_record_progress(unsigned long vernum);
-extern void do_trace_rcu_torture_read(const char *rcutorturename,
-				      struct rcu_head *rhp,
-				      unsigned long secs,
-				      unsigned long c_old,
-				      unsigned long c);
+void rcutorture_record_test_transition(void);
+void rcutorture_record_progress(unsigned long vernum);
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
 #else
 static inline void rcutorture_record_test_transition(void)
 {
···
 {
 }
 #ifdef CONFIG_RCU_TRACE
-extern void do_trace_rcu_torture_read(const char *rcutorturename,
-				      struct rcu_head *rhp,
-				      unsigned long secs,
-				      unsigned long c_old,
-				      unsigned long c);
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
 #else
 #define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
 	do { } while (0)
···
  * if CPU A and CPU B are the same CPU (but again only if the system has
  * more than one CPU).
  */
-extern void call_rcu(struct rcu_head *head,
-			      void (*func)(struct rcu_head *head));
+void call_rcu(struct rcu_head *head,
+	      void (*func)(struct rcu_head *head));
 
 #else /* #ifdef CONFIG_PREEMPT_RCU */
 
···
  * See the description of call_rcu() for more detailed information on
  * memory ordering guarantees.
  */
-extern void call_rcu_bh(struct rcu_head *head,
-			void (*func)(struct rcu_head *head));
+void call_rcu_bh(struct rcu_head *head,
+		 void (*func)(struct rcu_head *head));
 
 /**
  * call_rcu_sched() - Queue an RCU for invocation after sched grace period.
···
  * See the description of call_rcu() for more detailed information on
  * memory ordering guarantees.
  */
-extern void call_rcu_sched(struct rcu_head *head,
-			   void (*func)(struct rcu_head *rcu));
+void call_rcu_sched(struct rcu_head *head,
+		    void (*func)(struct rcu_head *rcu));
 
-extern void synchronize_sched(void);
+void synchronize_sched(void);
 
 #ifdef CONFIG_PREEMPT_RCU
 
-extern void __rcu_read_lock(void);
-extern void __rcu_read_unlock(void);
-extern void rcu_read_unlock_special(struct task_struct *t);
+void __rcu_read_lock(void);
+void __rcu_read_unlock(void);
+void rcu_read_unlock_special(struct task_struct *t);
 void synchronize_rcu(void);
 
 /*
···
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
 /* Internal to kernel */
-extern void rcu_init(void);
-extern void rcu_sched_qs(int cpu);
-extern void rcu_bh_qs(int cpu);
-extern void rcu_check_callbacks(int cpu, int user);
+void rcu_init(void);
+void rcu_sched_qs(int cpu);
+void rcu_bh_qs(int cpu);
+void rcu_check_callbacks(int cpu, int user);
 struct notifier_block;
-extern void rcu_idle_enter(void);
-extern void rcu_idle_exit(void);
-extern void rcu_irq_enter(void);
-extern void rcu_irq_exit(void);
+void rcu_idle_enter(void);
+void rcu_idle_exit(void);
+void rcu_irq_enter(void);
+void rcu_irq_exit(void);
 
 #ifdef CONFIG_RCU_USER_QS
-extern void rcu_user_enter(void);
-extern void rcu_user_exit(void);
+void rcu_user_enter(void);
+void rcu_user_exit(void);
 #else
 static inline void rcu_user_enter(void) { }
 static inline void rcu_user_exit(void) { }
···
 	} while (0)
 
 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP)
-extern bool __rcu_is_watching(void);
+bool __rcu_is_watching(void);
 #endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */
 
 /*
···
  * initialization.
  */
 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
-extern void init_rcu_head_on_stack(struct rcu_head *head);
-extern void destroy_rcu_head_on_stack(struct rcu_head *head);
+void init_rcu_head_on_stack(struct rcu_head *head);
+void destroy_rcu_head_on_stack(struct rcu_head *head);
 #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
 static inline void init_rcu_head_on_stack(struct rcu_head *head)
 {
···
  * rcu_read_lock_bh_held() is defined out of line to avoid #include-file
  * hell.
  */
-extern int rcu_read_lock_bh_held(void);
+int rcu_read_lock_bh_held(void);
 
 /**
  * rcu_read_lock_sched_held() - might we be in RCU-sched read-side critical section?
···
 
 #ifdef CONFIG_PROVE_RCU
 
-extern int rcu_my_thread_group_empty(void);
+int rcu_my_thread_group_empty(void);
 
 /**
  * rcu_lockdep_assert - emit lockdep splat if specified condition not met
···
 	__kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
 
 #ifdef CONFIG_RCU_NOCB_CPU
-extern bool rcu_is_nocb_cpu(int cpu);
+bool rcu_is_nocb_cpu(int cpu);
 #else
 static inline bool rcu_is_nocb_cpu(int cpu) { return false; }
 #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
···
 
 /* Only for use by adaptive-ticks code. */
 #ifdef CONFIG_NO_HZ_FULL_SYSIDLE
-extern bool rcu_sys_is_idle(void);
-extern void rcu_sysidle_force_exit(void);
+bool rcu_sys_is_idle(void);
+void rcu_sysidle_force_exit(void);
 #else /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
 
 static inline bool rcu_sys_is_idle(void)

include/linux/rcutiny.h

···
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 extern int rcu_scheduler_active __read_mostly;
-extern void rcu_scheduler_starting(void);
+void rcu_scheduler_starting(void);
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 static inline void rcu_scheduler_starting(void)
 {

include/linux/rcutree.h

···
 #ifndef __LINUX_RCUTREE_H
 #define __LINUX_RCUTREE_H
 
-extern void rcu_note_context_switch(int cpu);
-extern int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);
-extern void rcu_cpu_stall_reset(void);
+void rcu_note_context_switch(int cpu);
+int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);
+void rcu_cpu_stall_reset(void);
 
 /*
  * Note a virtualization-based context switch.  This is simply a
···
 	rcu_note_context_switch(cpu);
 }
 
-extern void synchronize_rcu_bh(void);
-extern void synchronize_sched_expedited(void);
-extern void synchronize_rcu_expedited(void);
+void synchronize_rcu_bh(void);
+void synchronize_sched_expedited(void);
+void synchronize_rcu_expedited(void);
 
 void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
 
···
 	synchronize_sched_expedited();
 }
 
-extern void rcu_barrier(void);
-extern void rcu_barrier_bh(void);
-extern void rcu_barrier_sched(void);
+void rcu_barrier(void);
+void rcu_barrier_bh(void);
+void rcu_barrier_sched(void);
 
 extern unsigned long rcutorture_testseq;
 extern unsigned long rcutorture_vernum;
-extern long rcu_batches_completed(void);
-extern long rcu_batches_completed_bh(void);
-extern long rcu_batches_completed_sched(void);
+long rcu_batches_completed(void);
+long rcu_batches_completed_bh(void);
+long rcu_batches_completed_sched(void);
 
-extern void rcu_force_quiescent_state(void);
-extern void rcu_bh_force_quiescent_state(void);
-extern void rcu_sched_force_quiescent_state(void);
+void rcu_force_quiescent_state(void);
+void rcu_bh_force_quiescent_state(void);
+void rcu_sched_force_quiescent_state(void);
 
-extern void exit_rcu(void);
+void exit_rcu(void);
 
-extern void rcu_scheduler_starting(void);
+void rcu_scheduler_starting(void);
 extern int rcu_scheduler_active __read_mostly;
 
-extern bool rcu_is_watching(void);
+bool rcu_is_watching(void);
 
 #endif /* __LINUX_RCUTREE_H */