srcu: Shrink srcu.h by moving docbook and private function

The call_srcu() docbook entry is currently in include/linux/srcu.h,
which causes needless processing for each include point.  This commit
therefore moves this entry to kernel/rcu/srcutree.c, which the compiler
reads only once.  In addition, the srcu_batches_completed() function is
used only within RCU and its torture-test suites.  This commit therefore
also moves this function's declaration from include/linux/srcutiny.h,
include/linux/srcutree.h, and include/linux/srcuclassic.h to
kernel/rcu/rcu.h.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/srcu.h

@@ -65,32 +65,12 @@ int init_srcu_struct(struct srcu_struct *sp);
 #elif defined(CONFIG_SRCU)
 #error "Unknown SRCU implementation specified to kernel configuration"
 #else
-
 /* Dummy definition for things like notifiers.  Actual use gets link error. */
 struct srcu_struct { };
-
 #endif
 
-/**
- * call_srcu() - Queue a callback for invocation after an SRCU grace period
- * @sp: srcu_struct in queue the callback
- * @head: structure to be used for queueing the SRCU callback.
- * @func: function to be invoked after the SRCU grace period
- *
- * The callback function will be invoked some time after a full SRCU
- * grace period elapses, in other words after all pre-existing SRCU
- * read-side critical sections have completed.  However, the callback
- * function might well execute concurrently with other SRCU read-side
- * critical sections that started after call_srcu() was invoked.  SRCU
- * read-side critical sections are delimited by srcu_read_lock() and
- * srcu_read_unlock(), and may be nested.
- *
- * The callback will be invoked from process context, but must nevertheless
- * be fast and must not block.
- */
 void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
 		void (*func)(struct rcu_head *head));
-
 void cleanup_srcu_struct(struct srcu_struct *sp);
 int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
 void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);

include/linux/srcuclassic.h

@@ -96,6 +96,5 @@ void process_srcu(struct work_struct *work);
 
 void synchronize_srcu_expedited(struct srcu_struct *sp);
 void srcu_barrier(struct srcu_struct *sp);
-unsigned long srcu_batches_completed(struct srcu_struct *sp);
 
 #endif

include/linux/srcutiny.h

@@ -88,9 +88,4 @@ static inline void srcu_barrier(struct srcu_struct *sp)
 	synchronize_srcu(sp);
 }
 
-static inline unsigned long srcu_batches_completed(struct srcu_struct *sp)
-{
-	return 0;
-}
-
 #endif

include/linux/srcutree.h

@@ -141,6 +141,5 @@ void process_srcu(struct work_struct *work);
 
 void synchronize_srcu_expedited(struct srcu_struct *sp);
 void srcu_barrier(struct srcu_struct *sp);
-unsigned long srcu_batches_completed(struct srcu_struct *sp);
 
 #endif

kernel/rcu/rcu.h

@@ -492,6 +492,11 @@ static inline unsigned long rcu_exp_batches_completed_sched(void)
 	return 0;
 }
 
+static inline unsigned long srcu_batches_completed(struct srcu_struct *sp)
+{
+	return 0;
+}
+
 static inline void rcu_force_quiescent_state(void)
 {
 }
@@ -519,6 +524,7 @@ unsigned long rcu_batches_completed_bh(void);
 unsigned long rcu_batches_completed_sched(void);
 unsigned long rcu_exp_batches_completed(void);
 unsigned long rcu_exp_batches_completed_sched(void);
+unsigned long srcu_batches_completed(struct srcu_struct *sp);
 void show_rcu_gp_kthreads(void);
 void rcu_force_quiescent_state(void);
 void rcu_bh_force_quiescent_state(void);

kernel/rcu/srcutree.c

@@ -854,6 +854,23 @@ void __call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
 		srcu_funnel_exp_start(sp, sdp->mynode, s);
 }
 
+/**
+ * call_srcu() - Queue a callback for invocation after an SRCU grace period
+ * @sp: srcu_struct in queue the callback
+ * @head: structure to be used for queueing the SRCU callback.
+ * @func: function to be invoked after the SRCU grace period
+ *
+ * The callback function will be invoked some time after a full SRCU
+ * grace period elapses, in other words after all pre-existing SRCU
+ * read-side critical sections have completed.  However, the callback
+ * function might well execute concurrently with other SRCU read-side
+ * critical sections that started after call_srcu() was invoked.  SRCU
+ * read-side critical sections are delimited by srcu_read_lock() and
+ * srcu_read_unlock(), and may be nested.
+ *
+ * The callback will be invoked from process context, but must nevertheless
+ * be fast and must not block.
+ */
 void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
 	       rcu_callback_t func)
 {