softirq: Move various protections into inline helpers

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>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309085727.310118772@linutronix.de

diff --git a/kernel/softirq.c b/kernel/softirq.c
index f1eb83dc3d508f9caf75790ae564c3f6449cae72..eaca3337dbdad204133d72c38db12217d086b871 100644 (file)
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -207,6 +207,32 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
 }
 EXPORT_SYMBOL(__local_bh_enable_ip);
 
+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()))
@@ -319,7 +345,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 
        pending = local_softirq_pending();
 
-       __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+       softirq_handle_begin();
        in_hardirq = lockdep_softirq_start();
        account_softirq_enter(current);
 
@@ -370,8 +396,7 @@ restart:
 
        account_softirq_exit(current);
        lockdep_softirq_end(in_hardirq);
-       __local_bh_enable(SOFTIRQ_OFFSET);
-       WARN_ON_ONCE(in_interrupt());
+       softirq_handle_end();
        current_restore_flags(old_flags, PF_MEMALLOC);
 }
 
@@ -466,7 +491,7 @@ inline void raise_softirq_irqoff(unsigned int nr)
         * Otherwise we wake up ksoftirqd to make sure we
         * schedule the softirq soon.
         */
-       if (!in_interrupt())
+       if (!in_interrupt() && should_wake_ksoftirqd())
                wakeup_softirqd();
 }
 
@@ -698,18 +723,18 @@ static int ksoftirqd_should_run(unsigned int cpu)
 
 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