linux-kernel - [RFC PATCH v2 1/4] irq: Move spurious_deferred bit from BIT(31) to BIT(0)

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Message-ID: <20240216075948.131372-3-leobras@redhat.com>
Date: Fri, 16 Feb 2024 04:59:43 -0300
From: Leonardo Bras <leobras@...hat.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Tony Lindgren <tony@...mide.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	John Ogness <john.ogness@...utronix.de>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Leonardo Bras <leobras@...hat.com>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Shanker Donthineni <sdonthineni@...dia.com>
Cc: linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org
Subject: [RFC PATCH v2 1/4] irq: Move spurious_deferred bit from BIT(31) to BIT(0)

Makes sure the threads_handled reserve a bit for that.
This will be useful in the next patch in this series.

Signed-off-by: Leonardo Bras <leobras@...hat.com>
---
 include/linux/irqdesc.h | 9 +++++++++
 kernel/irq/manage.c     | 4 ++--
 kernel/irq/spurious.c   | 6 ++----
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index d9451d456a733..62aff209315fe 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -251,4 +251,13 @@ irq_set_lockdep_class(unsigned int irq, struct lock_class_key *lock_class,
 		__irq_set_lockdep_class(irq, lock_class, request_class);
 }
 
+#define SPURIOUS_DEFERRED (0x1)
+#define SPURIOUS_DEFERRED_SHIFT (1)
+
+static inline void irq_add_handled(struct irq_desc *desc, int i)
+{
+	i <<= SPURIOUS_DEFERRED_SHIFT;
+	atomic_add(i, &desc->threads_handled);
+}
+
 #endif
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1782f90cd8c6c..5bc609c7b728c 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1191,7 +1191,7 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 		local_irq_disable();
 	ret = action->thread_fn(action->irq, action->dev_id);
 	if (ret == IRQ_HANDLED)
-		atomic_inc(&desc->threads_handled);
+		irq_add_handled(desc, 1);
 
 	irq_finalize_oneshot(desc, action);
 	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
@@ -1212,7 +1212,7 @@ static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 
 	ret = action->thread_fn(action->irq, action->dev_id);
 	if (ret == IRQ_HANDLED)
-		atomic_inc(&desc->threads_handled);
+		irq_add_handled(desc, 1);
 
 	irq_finalize_oneshot(desc, action);
 	return ret;
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index 02b2daf074414..d92f33b2e31ee 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -267,8 +267,6 @@ try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 	return action && (action->flags & IRQF_IRQPOLL);
 }
 
-#define SPURIOUS_DEFERRED	0x80000000
-
 void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
 {
 	unsigned int irq;
@@ -312,7 +310,7 @@ void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
 		if (action_ret == IRQ_WAKE_THREAD) {
 			int handled;
 			/*
-			 * We use bit 31 of thread_handled_last to
+			 * We use bit 0 of thread_handled_last to
 			 * denote the deferred spurious detection
 			 * active. No locking necessary as
 			 * thread_handled_last is only accessed here
@@ -328,7 +326,7 @@ void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
 			 * returned IRQ_HANDLED since the last
 			 * interrupt happened.
 			 *
-			 * For simplicity we just set bit 31, as it is
+			 * For simplicity we just set bit 0, as it is
 			 * set in threads_handled_last as well. So we
 			 * avoid extra masking. And we really do not
 			 * care about the high bits of the handled
-- 
2.43.2