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rcu: Eliminate rcu_irq_enter_disabled()

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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>
This commit is contained in:
Paul E. McKenney
2017-10-03 16:51:47 -07:00
parent 51a1fd30f1
commit 844ccdd7dc
5 changed files with 3 additions and 37 deletions
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kernel/rcu/tree.c
+2 -20
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@@ -270,20 +270,6 @@ static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
.dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR),
};
/*
* 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);
}
}