rcu: Eliminate rcu_irq_enter_disabled()

Now that the irq path uses the rcu_nmi_{enter,exit}() algorithm,
rcu_irq_enter() and rcu_irq_exit() may be used from any context.  There is
thus no need for rcu_irq_enter_disabled() and for the checks using it.
This commit therefore eliminates rcu_irq_enter_disabled().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 2 insertions, 20 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d123474fe829..444aa2b3f24d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -271,20 +271,6 @@ static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
 };
 
 /*
- * There's a few places, currently just in the tracing infrastructure,
- * that uses rcu_irq_enter() to make sure RCU is watching. But there's
- * a small location where that will not even work. In those cases
- * rcu_irq_enter_disabled() needs to be checked to make sure rcu_irq_enter()
- * can be called.
- */
-static DEFINE_PER_CPU(bool, disable_rcu_irq_enter);
-
-bool rcu_irq_enter_disabled(void)
-{
-        return this_cpu_read(disable_rcu_irq_enter);
-}
-
-/*
  * Record entry into an extended quiescent state.  This is only to be
  * called when not already in an extended quiescent state.
  */
@@ -792,10 +778,8 @@ static void rcu_eqs_enter_common(bool user)
                 do_nocb_deferred_wakeup(rdp);
         }
         rcu_prepare_for_idle();
-        __this_cpu_inc(disable_rcu_irq_enter);
-        rdtp->dynticks_nesting = 0; /* Breaks tracing momentarily. */
-        rcu_dynticks_eqs_enter(); /* After this, tracing works again. */
-        __this_cpu_dec(disable_rcu_irq_enter);
+        rdtp->dynticks_nesting = 0;
+        rcu_dynticks_eqs_enter();
         rcu_dynticks_task_enter();
 
         /*
@@ -1001,10 +985,8 @@ static void rcu_eqs_exit(bool user)
         if (oldval) {
                 rdtp->dynticks_nesting++;
         } else {
-                __this_cpu_inc(disable_rcu_irq_enter);
                 rcu_eqs_exit_common(1, user);
                 rdtp->dynticks_nesting = 1;
-                __this_cpu_dec(disable_rcu_irq_enter);
                 WRITE_ONCE(rdtp->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE);
         }
 }