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>
This commit is contained in:
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51a1fd30f1
commit
844ccdd7dc
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@ -111,7 +111,6 @@ static inline void rcu_cpu_stall_reset(void) { }
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static inline void rcu_idle_enter(void) { }
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static inline void rcu_idle_exit(void) { }
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static inline void rcu_irq_enter(void) { }
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static inline bool rcu_irq_enter_disabled(void) { return false; }
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static inline void rcu_irq_exit_irqson(void) { }
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static inline void rcu_irq_enter_irqson(void) { }
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static inline void rcu_irq_exit(void) { }
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@ -85,7 +85,6 @@ void rcu_irq_enter(void);
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void rcu_irq_exit(void);
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void rcu_irq_enter_irqson(void);
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void rcu_irq_exit_irqson(void);
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bool rcu_irq_enter_disabled(void);
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void exit_rcu(void);
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@ -137,11 +137,8 @@ extern void syscall_unregfunc(void);
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\
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if (!(cond)) \
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return; \
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if (rcucheck) { \
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if (WARN_ON_ONCE(rcu_irq_enter_disabled())) \
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return; \
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if (rcucheck) \
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rcu_irq_enter_irqson(); \
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} \
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rcu_read_lock_sched_notrace(); \
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it_func_ptr = rcu_dereference_sched((tp)->funcs); \
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if (it_func_ptr) { \
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@ -270,20 +270,6 @@ static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
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.dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR),
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};
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/*
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* There's a few places, currently just in the tracing infrastructure,
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* that uses rcu_irq_enter() to make sure RCU is watching. But there's
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* a small location where that will not even work. In those cases
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* rcu_irq_enter_disabled() needs to be checked to make sure rcu_irq_enter()
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* can be called.
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*/
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static DEFINE_PER_CPU(bool, disable_rcu_irq_enter);
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bool rcu_irq_enter_disabled(void)
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{
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return this_cpu_read(disable_rcu_irq_enter);
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}
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/*
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* Record entry into an extended quiescent state. This is only to be
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* called when not already in an extended quiescent state.
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@ -792,10 +778,8 @@ static void rcu_eqs_enter_common(bool user)
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do_nocb_deferred_wakeup(rdp);
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}
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rcu_prepare_for_idle();
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__this_cpu_inc(disable_rcu_irq_enter);
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rdtp->dynticks_nesting = 0; /* Breaks tracing momentarily. */
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rcu_dynticks_eqs_enter(); /* After this, tracing works again. */
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__this_cpu_dec(disable_rcu_irq_enter);
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rdtp->dynticks_nesting = 0;
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rcu_dynticks_eqs_enter();
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rcu_dynticks_task_enter();
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/*
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@ -1001,10 +985,8 @@ static void rcu_eqs_exit(bool user)
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if (oldval) {
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rdtp->dynticks_nesting++;
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} else {
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__this_cpu_inc(disable_rcu_irq_enter);
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rcu_eqs_exit_common(1, user);
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rdtp->dynticks_nesting = 1;
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__this_cpu_dec(disable_rcu_irq_enter);
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WRITE_ONCE(rdtp->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE);
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}
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}
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@ -2682,17 +2682,6 @@ void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
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if (unlikely(in_nmi()))
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return;
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/*
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* It is possible that a function is being traced in a
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* location that RCU is not watching. A call to
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* rcu_irq_enter() will make sure that it is, but there's
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* a few internal rcu functions that could be traced
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* where that wont work either. In those cases, we just
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* do nothing.
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*/
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if (unlikely(rcu_irq_enter_disabled()))
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return;
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rcu_irq_enter_irqson();
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__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
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rcu_irq_exit_irqson();
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