linux-kernel - [PATCH 5/5] irqchip: vt8500: Use fewer global variables and add error handling

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Message-Id: <20250424-vt8500-intc-updates-v1-5-4ab7397155b3@gmail.com>
Date: Thu, 24 Apr 2025 22:35:46 +0400
From: Alexey Charkov <alchark@...il.com>
To: Thomas Gleixner <tglx@...utronix.de>, 
 Krzysztof Kozlowski <krzk@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 Alexey Charkov <alchark@...il.com>
Subject: [PATCH 5/5] irqchip: vt8500: Use fewer global variables and add
 error handling

Controller private data doesn't really need to be in a global
statically allocated array - kzalloc it per controller instead,
keeping only one pointer to the primary controller global.

While at that, also add proper error return statuses in the init
path and respective cleanup of resources on errors.

Signed-off-by: Alexey Charkov <alchark@...il.com>
---
 drivers/irqchip/irq-vt8500.c | 49 +++++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 23 deletions(-)

diff --git a/drivers/irqchip/irq-vt8500.c b/drivers/irqchip/irq-vt8500.c
index aea43c838430d2a541aa9b3127a215531abecad8..0bf478c6541ede30719eb1e403d9cafe6474643a 100644
--- a/drivers/irqchip/irq-vt8500.c
+++ b/drivers/irqchip/irq-vt8500.c
@@ -64,9 +64,6 @@ struct vt8500_irq_data {
 	struct irq_domain	*domain;	/* Domain for this controller */
 };
 
-/* Global variable for accessing io-mem addresses */
-static struct vt8500_irq_data intc[VT8500_INTC_MAX];
-static u32 active_cnt = 0;
 /* Primary interrupt controller data */
 static struct vt8500_irq_data *primary_intc;
 
@@ -203,50 +200,56 @@ static void vt8500_handle_irq_chained(struct irq_desc *desc)
 static int __init vt8500_irq_init(struct device_node *node,
 				  struct device_node *parent)
 {
-	int irq, i;
+	struct vt8500_irq_data *intc;
+	int irq, i, ret = 0;
 
-	if (active_cnt == VT8500_INTC_MAX) {
-		pr_err("%s: Interrupt controllers > VT8500_INTC_MAX\n",
-								__func__);
-		goto out;
-	}
-
-	intc[active_cnt].base = of_iomap(node, 0);
-	intc[active_cnt].domain = irq_domain_add_linear(node, 64,
-			&vt8500_irq_domain_ops,	&intc[active_cnt]);
+	intc = kzalloc(sizeof(*intc), GFP_KERNEL);
+	if (!intc)
+		return -ENOMEM;
 
-	if (!intc[active_cnt].base) {
+	intc->base = of_iomap(node, 0);
+	if (!intc->base) {
 		pr_err("%s: Unable to map IO memory\n", __func__);
-		goto out;
+		ret = -ENOMEM;
+		goto err_free;
 	}
 
-	if (!intc[active_cnt].domain) {
+	intc->domain = irq_domain_add_linear(node,
+					     64,
+					     &vt8500_irq_domain_ops,
+					     intc);
+	if (!intc->domain) {
 		pr_err("%s: Unable to add irq domain!\n", __func__);
-		goto out;
+		ret = -ENOMEM;
+		goto err_unmap;
 	}
 
-	vt8500_init_irq_hw(intc[active_cnt].base);
+	vt8500_init_irq_hw(intc->base);
 
 	pr_info("vt8500-irq: Added interrupt controller\n");
 
-	active_cnt++;
-
 	/* check if this is a chained controller */
 	if (of_irq_count(node) != 0) {
 		for (i = 0; i < of_irq_count(node); i++) {
 			irq = irq_of_parse_and_map(node, i);
 			irq_set_chained_handler_and_data(irq,
 				vt8500_handle_irq_chained,
-				&intc[active_cnt]);
+				intc);
 		}
 
 		pr_info("vt8500-irq: Enabled slave->parent interrupts\n");
 	} else {
-		primary_intc = &intc[active_cnt];
+		primary_intc = intc;
 		set_handle_irq(vt8500_handle_irq);
 	}
-out:
+
 	return 0;
+
+err_unmap:
+	iounmap(intc->base);
+err_free:
+	kfree(intc);
+	return ret;
 }
 
 IRQCHIP_DECLARE(vt8500_irq, "via,vt8500-intc", vt8500_irq_init);

-- 
2.49.0