[RFC PATCH 2/3] lockdep: Merge hardirq_threaded and irq_config together

From: Frederic Weisbecker
Date: Sun Mar 22 2020 - 23:32:27 EST


These fields describe the same state: a code block running in hardirq
that might be threaded under specific configurations.

Merge them together in the same field. Also rename the result as
"hardirq_threadable" as we are talking about a possible state and not
an actual one.

While at it remove the posix cpu timer lockdep functions since we can
call into trace_hardirq_[un]threadable() directly. The need for hrtimer
binders is debatable as well.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
include/linux/irqflags.h | 70 ++++++++++++++--------------------
include/linux/sched.h | 3 +-
kernel/irq/handle.c | 4 +-
kernel/locking/lockdep.c | 2 +-
kernel/time/posix-cpu-timers.c | 6 +--
5 files changed, 35 insertions(+), 50 deletions(-)

diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 28481702460e..f69f93839760 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -45,14 +45,14 @@ do { \
current->hardirq_context--; \
} while (0)

-# define trace_hardirq_threaded() \
+# define trace_hardirq_threadable() \
do { \
- current->hardirq_threaded = 1; \
+ current->hardirq_threadable = 1; \
} while (0)

-# define trace_hardirq_unthreaded() \
+# define trace_hardirq_unthreadable() \
do { \
- current->hardirq_threaded = 0; \
+ current->hardirq_threadable = 0; \
} while (0)

# define lockdep_softirq_enter() \
@@ -64,38 +64,16 @@ do { \
current->softirq_context--; \
} while (0)

-# define lockdep_hrtimer_enter(__hrtimer) \
- do { \
- if (!__hrtimer->is_hard) \
- current->irq_config = 1; \
- } while (0)
-
-# define lockdep_hrtimer_exit(__hrtimer) \
- do { \
- if (!__hrtimer->is_hard) \
- current->irq_config = 0; \
- } while (0)
-
-# define lockdep_posixtimer_enter() \
- do { \
- current->irq_config = 1; \
- } while (0)
-
-# define lockdep_posixtimer_exit() \
- do { \
- current->irq_config = 0; \
- } while (0)
-
# define lockdep_irq_work_enter(__work) \
- do { \
- if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ))\
- current->irq_config = 1; \
- } while (0)
+do { \
+ if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ)) \
+ trace_hardirq_threadable(); \
+} while (0)
# define lockdep_irq_work_exit(__work) \
- do { \
- if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ))\
- current->irq_config = 0; \
- } while (0)
+do { \
+ if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ)) \
+ trace_hardirq_unthreadable(); \
+} while (0)

#else
# define trace_hardirqs_on() do { } while (0)
@@ -106,18 +84,26 @@ do { \
# define trace_softirqs_enabled(p) 0
# define trace_hardirq_enter() do { } while (0)
# define trace_hardirq_exit() do { } while (0)
-# define trace_hardirq_threaded() do { } while (0)
-# define trace_hardirq_unthreaded() do { } while (0)
+# define trace_hardirq_threadable() do { } while (0)
+# define trace_hardirq_unthreadable() do { } while (0)
# define lockdep_softirq_enter() do { } while (0)
# define lockdep_softirq_exit() do { } while (0)
-# define lockdep_hrtimer_enter(__hrtimer) do { } while (0)
-# define lockdep_hrtimer_exit(__hrtimer) do { } while (0)
-# define lockdep_posixtimer_enter() do { } while (0)
-# define lockdep_posixtimer_exit() do { } while (0)
-# define lockdep_irq_work_enter(__work) do { } while (0)
-# define lockdep_irq_work_exit(__work) do { } while (0)
+# define lockdep_irq_work_enter(__work) do { } while (0)
+# define lockdep_irq_work_exit(__work) do { } while (0)
#endif

+# define lockdep_hrtimer_enter(__hrtimer) \
+do { \
+ if (!__hrtimer->is_hard) \
+ trace_hardirq_threadable(); \
+} while (0)
+
+# define lockdep_hrtimer_exit(__hrtimer) \
+do { \
+ if (!__hrtimer->is_hard) \
+ trace_hardirq_unthreadable(); \
+} while (0)
+
#if defined(CONFIG_IRQSOFF_TRACER) || \
defined(CONFIG_PREEMPT_TRACER)
extern void stop_critical_timings(void);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 933914cdf219..9918d23b53e7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -970,7 +970,7 @@ struct task_struct {

#ifdef CONFIG_TRACE_IRQFLAGS
unsigned int irq_events;
- unsigned int hardirq_threaded;
+ unsigned int hardirq_threadable;
unsigned long hardirq_enable_ip;
unsigned long hardirq_disable_ip;
unsigned int hardirq_enable_event;
@@ -983,7 +983,6 @@ struct task_struct {
unsigned int softirq_enable_event;
int softirqs_enabled;
int softirq_context;
- int irq_config;
#endif

#ifdef CONFIG_LOCKDEP
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 39d6cf9f5853..55405879b8ad 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -153,14 +153,14 @@ irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags
!(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)));

if (threadable)
- trace_hardirq_threaded();
+ trace_hardirq_threadable();

trace_irq_handler_entry(irq, action);
res = action->handler(irq, action->dev_id);
trace_irq_handler_exit(irq, action, res);

if (threadable)
- trace_hardirq_unthreaded();
+ trace_hardirq_unthreadable();

if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n",
irq, action->handler))
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 0ebf9807d971..1cebaeb790a0 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4025,7 +4025,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
/*
* Check if force_irqthreads will run us threaded.
*/
- if (curr->hardirq_threaded || curr->irq_config)
+ if (curr->hardirq_threadable)
curr_inner = LD_WAIT_CONFIG;
else
curr_inner = LD_WAIT_SPIN;
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 2c48a7233b19..d29a06d60206 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1126,9 +1126,9 @@ void run_posix_cpu_timers(void)
if (!fastpath_timer_check(tsk))
return;

- lockdep_posixtimer_enter();
+ trace_hardirq_threadable();
if (!lock_task_sighand(tsk, &flags)) {
- lockdep_posixtimer_exit();
+ trace_hardirq_unthreadable();
return;
}
/*
@@ -1172,7 +1172,7 @@ void run_posix_cpu_timers(void)
cpu_timer_fire(timer);
spin_unlock(&timer->it_lock);
}
- lockdep_posixtimer_exit();
+ trace_hardirq_unthreadable();
}

/*
--
2.25.0