rcu: Remove unused 'cpu' in rcu_virt_note_context_switch()

This commit removes the unused function argument 'cpu'.  This does not
change functionality, but might save a cycle or two.

Signed-off-by: Zeng Heng <[email protected]>
Acked-by: Mukesh Ojha <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

Author: henryZe

include/linux/kvm_host.h

@@ -417,7 +417,7 @@ static __always_inline void guest_context_enter_irqoff(void)
 	 */
 	if (!context_tracking_guest_enter()) {
 		instrumentation_begin();
-		rcu_virt_note_context_switch(smp_processor_id());
+		rcu_virt_note_context_switch();
 		instrumentation_end();
 	}
 }

include/linux/rcutiny.h

@@ -142,7 +142,7 @@ static inline int rcu_needs_cpu(void)
  * Take advantage of the fact that there is only one CPU, which
  * allows us to ignore virtualization-based context switches.
  */
-static inline void rcu_virt_note_context_switch(int cpu) { }
+static inline void rcu_virt_note_context_switch(void) { }
 static inline void rcu_cpu_stall_reset(void) { }
 static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
 static inline void rcu_irq_exit_check_preempt(void) { }

include/linux/rcutree.h

@@ -27,7 +27,7 @@ void rcu_cpu_stall_reset(void);
  * 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)
+static inline void rcu_virt_note_context_switch(void)
 {
 	rcu_note_context_switch(false);
 }