rcu: Remove rcu_switch()

It's only there to call rcu_user_hooks_switch(). Let's
just call rcu_user_hooks_switch() directly, we don't need this
function in the middle.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

arch/um/drivers/mconsole_kern.c

@@ -648,7 +648,7 @@ static void stack_proc(void *arg)
 	struct task_struct *from = current, *to = arg;
 
 	to->thread.saved_task = from;
-	rcu_switch(from, to);
+	rcu_user_hooks_switch(from, to);
 	switch_to(from, to, from);
 }
 

include/linux/rcupdate.h

@@ -204,6 +204,8 @@ static inline void rcu_user_enter(void) { }
 static inline void rcu_user_exit(void) { }
 static inline void rcu_user_enter_after_irq(void) { }
 static inline void rcu_user_exit_after_irq(void) { }
+static inline void rcu_user_hooks_switch(struct task_struct *prev,
+					 struct task_struct *next) { }
 #endif /* CONFIG_RCU_USER_QS */
 
 extern void exit_rcu(void);

include/linux/sched.h

@@ -1844,14 +1844,6 @@ static inline void rcu_copy_process(struct task_struct *p)
 
 #endif
 
-static inline void rcu_switch(struct task_struct *prev,
-			      struct task_struct *next)
-{
-#ifdef CONFIG_RCU_USER_QS
-	rcu_user_hooks_switch(prev, next);
-#endif
-}
-
 static inline void tsk_restore_flags(struct task_struct *task,
 				unsigned long orig_flags, unsigned long flags)
 {

kernel/sched/core.c

@@ -1887,7 +1887,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
 #endif
 
 	/* Here we just switch the register state and the stack. */
-	rcu_switch(prev, next);
+	rcu_user_hooks_switch(prev, next);
 	switch_to(prev, next, prev);
 
 	barrier();