irq: Call tick_irq_enter() inside HARDIRQ_OFFSET

Now that account_hardirq_enter() is called after HARDIRQ_OFFSET has
been incremented, there is nothing left that prevents us from also
moving tick_irq_enter() after HARDIRQ_OFFSET is incremented.

The desired outcome is to remove the nasty hack that prevents softirqs
from being raised through ksoftirqd instead of the hardirq bottom half.
Also tick_irq_enter() then becomes appropriately covered by lockdep.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201202115732.27827-6-frederic@kernel.org

diff --git a/kernel/softirq.c b/kernel/softirq.c
index b8f42b3..d5bfd5e 100644 (file)
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -377,16 +377,12 @@ restart:
  */
 void irq_enter_rcu(void)
 {
-       if (is_idle_task(current) && !in_interrupt()) {
-               /*
-                * Prevent raise_softirq from needlessly waking up ksoftirqd
-                * here, as softirq will be serviced on return from interrupt.
-                */
-               local_bh_disable();
+       __irq_enter_raw();
+
+       if (is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET))
                tick_irq_enter();
-               _local_bh_enable();
-       }
-       __irq_enter();
+
+       account_hardirq_enter(current);
 }
 
 /**