linux-kernel - [PATCH v2 1/3] genirq: enhance error recovery code in free irq

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Date:   Mon, 12 Aug 2019 16:52:04 +0800
From:   Ben Luo <luoben@...ux.alibaba.com>
To:     tglx@...utronix.de, alex.williamson@...hat.com,
        linux-kernel@...r.kernel.org
Cc:     tao.ma@...ux.alibaba.com, gerry@...ux.alibaba.com,
        nanhai.zou@...ux.alibaba.com, linyunsheng@...wei.com
Subject: [PATCH v2 1/3] genirq: enhance error recovery code in free irq

Per Thomas Gleixner's comments:
1) free_irq/free_percpu_irq returns if called from IRQ context
2) move WARN out of the locked region and print out dev_id

Signed-off-by: Ben Luo <luoben@...ux.alibaba.com>
---
 kernel/irq/manage.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e8f7f17..b97ee5e 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1690,7 +1690,11 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
 	struct irqaction *action, **action_ptr;
 	unsigned long flags;
 
-	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+	if (in_interrupt()) {
+		WARN(1, "Trying to free IRQ %d (dev_id %p) from IRQ context!\n",
+				irq, dev_id);
+		return NULL;
+	}
 
 	mutex_lock(&desc->request_mutex);
 	chip_bus_lock(desc);
@@ -1705,10 +1709,11 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
 		action = *action_ptr;
 
 		if (!action) {
-			WARN(1, "Trying to free already-free IRQ %d\n", irq);
 			raw_spin_unlock_irqrestore(&desc->lock, flags);
 			chip_bus_sync_unlock(desc);
 			mutex_unlock(&desc->request_mutex);
+			WARN(1, "Trying to free already-free IRQ %d (dev_id %p)\n",
+					irq, dev_id);
 			return NULL;
 		}
 
@@ -2286,7 +2291,11 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
 	struct irqaction *action;
 	unsigned long flags;
 
-	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+	if (in_interrupt()) {
+		WARN(1, "Trying to free IRQ %d (dev_id %p) from IRQ context!\n",
+				irq, dev_id);
+		return NULL;
+	}
 
 	if (!desc)
 		return NULL;
@@ -2295,14 +2304,17 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
 
 	action = desc->action;
 	if (!action || action->percpu_dev_id != dev_id) {
-		WARN(1, "Trying to free already-free IRQ %d\n", irq);
-		goto bad;
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+		WARN(1, "Trying to free already-free IRQ (dev_id %p) %d\n",
+				irq, dev_id);
+		return NULL;
 	}
 
 	if (!cpumask_empty(desc->percpu_enabled)) {
-		WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
-		     irq, cpumask_first(desc->percpu_enabled));
-		goto bad;
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+		WARN(1, "percpu IRQ %d (dev_id %p) still enabled on CPU%d!\n",
+		     irq, dev_id, cpumask_first(desc->percpu_enabled));
+		return NULL;
 	}
 
 	/* Found it - now remove it from the list of entries: */
@@ -2317,10 +2329,6 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
 	irq_chip_pm_put(&desc->irq_data);
 	module_put(desc->owner);
 	return action;
-
-bad:
-	raw_spin_unlock_irqrestore(&desc->lock, flags);
-	return NULL;
 }
 
 /**
-- 
1.8.3.1