[patch 13/19] softirq: Move various protections into inline helpers

Thomas Gleixner
2020-11-13T14:25:14Z

To allow reuse of the bulk of softirq processing code for RT and to avoid
#ifdeffery all over the place, split protections for various code sections
out into inline helpers so the RT variant can just replace them in one go.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/softirq.c | 53 ++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 44 insertions(+), 9 deletions(-)

--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -204,6 +204,42 @@ void __local_bh_enable_ip(unsigned long
}
EXPORT_SYMBOL(__local_bh_enable_ip);

+static inline void local_bh_disable_irq_enter(void)
+{
+ local_bh_disable();
+}
+
+static inline void local_bh_enable_irq_enter(void)
+{
+ _local_bh_enable();
+}
+
+static inline void softirq_handle_begin(void)
+{
+ __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+}
+
+static inline void softirq_handle_end(void)
+{
+ __local_bh_enable(SOFTIRQ_OFFSET);
+ WARN_ON_ONCE(in_interrupt());
+}
+
+static inline void ksoftirqd_run_begin(void)
+{
+ local_irq_disable();
+}
+
+static inline void ksoftirqd_run_end(void)
+{
+ local_irq_enable();
+}
+
+static inline bool should_wake_ksoftirqd(void)
+{
+ return true;
+}
+
static inline void invoke_softirq(void)
{
if (ksoftirqd_running(local_softirq_pending()))
@@ -317,7 +353,7 @@ asmlinkage __visible void __softirq_entr
pending = local_softirq_pending();
account_irq_enter_time(current);

- __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+ softirq_handle_begin();
in_hardirq = lockdep_softirq_start();

restart:
@@ -367,8 +403,7 @@ asmlinkage __visible void __softirq_entr

lockdep_softirq_end(in_hardirq);
account_irq_exit_time(current);
- __local_bh_enable(SOFTIRQ_OFFSET);
- WARN_ON_ONCE(in_interrupt());
+ softirq_handle_end();
current_restore_flags(old_flags, PF_MEMALLOC);
}

@@ -382,9 +417,9 @@ void irq_enter_rcu(void)
* Prevent raise_softirq from needlessly waking up ksoftirqd
* here, as softirq will be serviced on return from interrupt.
*/
- local_bh_disable();
+ local_bh_disable_irq_enter();
tick_irq_enter();
- _local_bh_enable();
+ local_bh_enable_irq_enter();
}
__irq_enter();
}
@@ -467,7 +502,7 @@ inline void raise_softirq_irqoff(unsigne
* Otherwise we wake up ksoftirqd to make sure we
* schedule the softirq soon.
*/
- if (!in_interrupt())
+ if (!in_interrupt() && should_wake_ksoftirqd())
wakeup_softirqd();
}

@@ -645,18 +680,18 @@ static int ksoftirqd_should_run(unsigned

static void run_ksoftirqd(unsigned int cpu)
{
- local_irq_disable();
+ ksoftirqd_run_begin();
if (local_softirq_pending()) {
/*
* We can safely run softirq on inline stack, as we are not deep
* in the task stack here.
*/
__do_softirq();
- local_irq_enable();
+ ksoftirqd_run_end();
cond_resched();
return;
}
- local_irq_enable();
+ ksoftirqd_run_end();
}

#ifdef CONFIG_HOTPLUG_CPU