[tip: irq/core] genirq/irq_sim: Make the irq_work always run in hard irq context

["tip-bot2 for Sebastian Andrzej Siewior" <tip-bot2@linutronix.de>]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     21673fcb2532dcd189905ff5a5389eb7dcd0e57a
Gitweb:        https://git.kernel.org/tip/21673fcb2532dcd189905ff5a5389eb7dcd0e57a
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Wed, 11 May 2022 13:07:50 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 14 May 2022 17:48:27 +02:00

genirq/irq_sim: Make the irq_work always run in hard irq context

The IRQ simulator uses irq_work to trigger an interrupt. Without the
IRQ_WORK_HARD_IRQ flag the irq_work will be performed in thread context
on PREEMPT_RT. This causes locking errors later in handle_simple_irq()
which expects to be invoked with disabled interrupts.

Triggering individual interrupts in hardirq context should not lead to
unexpected high latencies since this is also what the hardware
controller does. Also it is used as a simulator so...

Use IRQ_WORK_INIT_HARD() to carry out the irq_work in hardirq context on
PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/YnuZBoEVMGwKkLm+@linutronix.de
---
 kernel/irq/irq_sim.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
index 0cd02ef..dd76323 100644
--- a/kernel/irq/irq_sim.c
+++ b/kernel/irq/irq_sim.c
@@ -181,7 +181,7 @@ struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
 		goto err_free_bitmap;
 
 	work_ctx->irq_count = num_irqs;
-	init_irq_work(&work_ctx->work, irq_sim_handle_irq);
+	work_ctx->work = IRQ_WORK_INIT_HARD(irq_sim_handle_irq);
 
 	return work_ctx->domain;