linux-kernel - [PATCH v3 10/19] irqdomain: Clean up irq_domain_push/pop

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Date:   Fri,  9 Dec 2022 15:01:41 +0100
From:   Johan Hovold <johan+linaro@...nel.org>
To:     Marc Zyngier <maz@...nel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        platform-driver-x86@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Johan Hovold <johan+linaro@...nel.org>
Subject: [PATCH v3 10/19] irqdomain: Clean up irq_domain_push/pop_irq()

The irq_domain_push_irq() interface is used to add a new (outmost) level
to a hierarchical domain after IRQs have been allocated.

Possibly due to differing mental images of hierarchical domains, the
names used for the irq_data variables make these functions much harder
to understand than what they need to be.

Rename the struct irq_data pointer to the data embedded in the
descriptor as simply 'irq_data' and refer to the data allocated by this
interface as 'parent_irq_data' so that the names reflect how
hierarchical domains are implemented.

Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 kernel/irq/irqdomain.c | 65 +++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 7232947eee3e..6f2b8a1248e1 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1571,8 +1571,8 @@ static void irq_domain_fix_revmap(struct irq_data *d)
  */
 int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
 {
-	struct irq_data *child_irq_data;
-	struct irq_data *root_irq_data = irq_get_irq_data(virq);
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+	struct irq_data *parent_irq_data;
 	struct irq_desc *desc;
 	int rv = 0;
 
@@ -1597,45 +1597,44 @@ int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
 	if (WARN_ON(!irq_domain_is_hierarchy(domain)))
 		return -EINVAL;
 
-	if (!root_irq_data)
+	if (!irq_data)
 		return -EINVAL;
 
-	if (domain->parent != root_irq_data->domain)
+	if (domain->parent != irq_data->domain)
 		return -EINVAL;
 
-	child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,
-				      irq_data_get_node(root_irq_data));
-	if (!child_irq_data)
+	parent_irq_data = kzalloc_node(sizeof(*parent_irq_data), GFP_KERNEL,
+				       irq_data_get_node(irq_data));
+	if (!parent_irq_data)
 		return -ENOMEM;
 
 	mutex_lock(&irq_domain_mutex);
 
 	/* Copy the original irq_data. */
-	*child_irq_data = *root_irq_data;
+	*parent_irq_data = *irq_data;
 
 	/*
-	 * Overwrite the root_irq_data, which is embedded in struct
-	 * irq_desc, with values for this domain.
+	 * Overwrite the irq_data, which is embedded in struct irq_desc, with
+	 * values for this domain.
 	 */
-	root_irq_data->parent_data = child_irq_data;
-	root_irq_data->domain = domain;
-	root_irq_data->mask = 0;
-	root_irq_data->hwirq = 0;
-	root_irq_data->chip = NULL;
-	root_irq_data->chip_data = NULL;
+	irq_data->parent_data = parent_irq_data;
+	irq_data->domain = domain;
+	irq_data->mask = 0;
+	irq_data->hwirq = 0;
+	irq_data->chip = NULL;
+	irq_data->chip_data = NULL;
 
 	/* May (probably does) set hwirq, chip, etc. */
 	rv = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
 	if (rv) {
 		/* Restore the original irq_data. */
-		*root_irq_data = *child_irq_data;
-		kfree(child_irq_data);
+		*irq_data = *parent_irq_data;
+		kfree(parent_irq_data);
 		goto error;
 	}
 
-	irq_domain_fix_revmap(child_irq_data);
-	irq_domain_set_mapping(domain, root_irq_data->hwirq, root_irq_data);
-
+	irq_domain_fix_revmap(parent_irq_data);
+	irq_domain_set_mapping(domain, irq_data->hwirq, irq_data);
 error:
 	mutex_unlock(&irq_domain_mutex);
 
@@ -1653,8 +1652,8 @@ EXPORT_SYMBOL_GPL(irq_domain_push_irq);
  */
 int irq_domain_pop_irq(struct irq_domain *domain, int virq)
 {
-	struct irq_data *root_irq_data = irq_get_irq_data(virq);
-	struct irq_data *child_irq_data;
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+	struct irq_data *parent_irq_data;
 	struct irq_data *tmp_irq_data;
 	struct irq_desc *desc;
 
@@ -1676,37 +1675,37 @@ int irq_domain_pop_irq(struct irq_domain *domain, int virq)
 	if (domain == NULL)
 		return -EINVAL;
 
-	if (!root_irq_data)
+	if (!irq_data)
 		return -EINVAL;
 
 	tmp_irq_data = irq_domain_get_irq_data(domain, virq);
 
 	/* We can only "pop" if this domain is at the top of the list */
-	if (WARN_ON(root_irq_data != tmp_irq_data))
+	if (WARN_ON(irq_data != tmp_irq_data))
 		return -EINVAL;
 
-	if (WARN_ON(root_irq_data->domain != domain))
+	if (WARN_ON(irq_data->domain != domain))
 		return -EINVAL;
 
-	child_irq_data = root_irq_data->parent_data;
-	if (WARN_ON(!child_irq_data))
+	parent_irq_data = irq_data->parent_data;
+	if (WARN_ON(!parent_irq_data))
 		return -EINVAL;
 
 	mutex_lock(&irq_domain_mutex);
 
-	root_irq_data->parent_data = NULL;
+	irq_data->parent_data = NULL;
 
-	irq_domain_clear_mapping(domain, root_irq_data->hwirq);
+	irq_domain_clear_mapping(domain, irq_data->hwirq);
 	irq_domain_free_irqs_hierarchy(domain, virq, 1);
 
 	/* Restore the original irq_data. */
-	*root_irq_data = *child_irq_data;
+	*irq_data = *parent_irq_data;
 
-	irq_domain_fix_revmap(root_irq_data);
+	irq_domain_fix_revmap(irq_data);
 
 	mutex_unlock(&irq_domain_mutex);
 
-	kfree(child_irq_data);
+	kfree(parent_irq_data);
 
 	return 0;
 }
-- 
2.37.4