[PATCH v2 5/5] genirq: Introduce generic init_desc()

[Dawei Li]

Those two functions below share much duplicated codes for
initialization for irq_desc:
- alloc_desc() CONFIG_SPARSE_IRQ
- early_irq_init() !CONFIG_SPARSE_IRQ

Implement a dedicated function to fully initialize irq_desc.

Also, make free_masks() global to implement exception handling in
early_irq_init.

Suggested-by: Marc Zyngier <maz at kernel.org>
Signed-off-by: Dawei Li <dawei.li at shingroup.cn>
---
 kernel/irq/irqdesc.c | 112 ++++++++++++++++++++++++-------------------
 1 file changed, 64 insertions(+), 48 deletions(-)

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 371eb1711d34..4c6b32318ce3 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -92,11 +92,23 @@ static void desc_smp_init(struct irq_desc *desc, int node,
 #endif
 }
 
+static void free_masks(struct irq_desc *desc)
+{
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	free_cpumask_var(desc->pending_mask);
+#endif
+	free_cpumask_var(desc->irq_common_data.affinity);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	free_cpumask_var(desc->irq_common_data.effective_affinity);
+#endif
+}
+
 #else
 static inline int
 alloc_masks(struct irq_desc *desc, int node) { return 0; }
 static inline void
 desc_smp_init(struct irq_desc *desc, int node, const struct cpumask *affinity) { }
+static inline void free_masks(struct irq_desc *desc) { }
 #endif
 
 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
@@ -165,6 +177,39 @@ static void delete_irq_desc(unsigned int irq)
 	mas_erase(&mas);
 }
 
+#ifdef CONFIG_SPARSE_IRQ
+static const struct kobj_type irq_kobj_type;
+#endif
+
+static int init_desc(struct irq_desc *desc, int irq, int node,
+		     unsigned int flags,
+		     const struct cpumask *affinity,
+		     struct module *owner)
+{
+	desc->kstat_irqs = alloc_percpu(unsigned int);
+	if (!desc->kstat_irqs)
+		return -ENOMEM;
+
+	if (alloc_masks(desc, node)) {
+		free_percpu(desc->kstat_irqs);
+		return -ENOMEM;
+	}
+
+	raw_spin_lock_init(&desc->lock);
+	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+	mutex_init(&desc->request_mutex);
+	init_waitqueue_head(&desc->wait_for_threads);
+	desc_set_defaults(irq, desc, node, affinity, owner);
+	irqd_set(&desc->irq_data, flags);
+	irq_resend_init(desc);
+#ifdef CONFIG_SPARSE_IRQ
+	kobject_init(&desc->kobj, &irq_kobj_type);
+	init_rcu_head(&desc->rcu);
+#endif
+
+	return 0;
+}
+
 #ifdef CONFIG_SPARSE_IRQ
 
 static void irq_kobj_release(struct kobject *kobj);
@@ -384,21 +429,6 @@ struct irq_desc *irq_to_desc(unsigned int irq)
 EXPORT_SYMBOL_GPL(irq_to_desc);
 #endif
 
-#ifdef CONFIG_SMP
-static void free_masks(struct irq_desc *desc)
-{
-#ifdef CONFIG_GENERIC_PENDING_IRQ
-	free_cpumask_var(desc->pending_mask);
-#endif
-	free_cpumask_var(desc->irq_common_data.affinity);
-#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
-	free_cpumask_var(desc->irq_common_data.effective_affinity);
-#endif
-}
-#else
-static inline void free_masks(struct irq_desc *desc) { }
-#endif
-
 void irq_lock_sparse(void)
 {
 	mutex_lock(&sparse_irq_lock);
@@ -414,36 +444,19 @@ static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
 				   struct module *owner)
 {
 	struct irq_desc *desc;
+	int ret;
 
 	desc = kzalloc_node(sizeof(*desc), GFP_KERNEL, node);
 	if (!desc)
 		return NULL;
-	/* allocate based on nr_cpu_ids */
-	desc->kstat_irqs = alloc_percpu(unsigned int);
-	if (!desc->kstat_irqs)
-		goto err_desc;
-
-	if (alloc_masks(desc, node))
-		goto err_kstat;
 
-	raw_spin_lock_init(&desc->lock);
-	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
-	mutex_init(&desc->request_mutex);
-	init_rcu_head(&desc->rcu);
-	init_waitqueue_head(&desc->wait_for_threads);
-
-	desc_set_defaults(irq, desc, node, affinity, owner);
-	irqd_set(&desc->irq_data, flags);
-	kobject_init(&desc->kobj, &irq_kobj_type);
-	irq_resend_init(desc);
+	ret = init_desc(desc, irq, node, flags, affinity, owner);
+	if (unlikely(ret)) {
+		kfree(desc);
+		return NULL;
+	}
 
 	return desc;
-
-err_kstat:
-	free_percpu(desc->kstat_irqs);
-err_desc:
-	kfree(desc);
-	return NULL;
 }
 
 static void irq_kobj_release(struct kobject *kobj)
@@ -583,26 +596,29 @@ struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 int __init early_irq_init(void)
 {
 	int count, i, node = first_online_node;
-	struct irq_desc *desc;
+	int ret;
 
 	init_irq_default_affinity();
 
 	printk(KERN_INFO "NR_IRQS: %d\n", NR_IRQS);
 
-	desc = irq_desc;
 	count = ARRAY_SIZE(irq_desc);
 
 	for (i = 0; i < count; i++) {
-		desc[i].kstat_irqs = alloc_percpu(unsigned int);
-		alloc_masks(&desc[i], node);
-		raw_spin_lock_init(&desc[i].lock);
-		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
-		mutex_init(&desc[i].request_mutex);
-		init_waitqueue_head(&desc[i].wait_for_threads);
-		desc_set_defaults(i, &desc[i], node, NULL, NULL);
-		irq_resend_init(&desc[i]);
+		ret = init_desc(irq_desc + i, i, node, 0, NULL, NULL);
+		if (unlikely(ret))
+			goto __free_desc_res;
 	}
+
 	return arch_early_irq_init();
+
+__free_desc_res:
+	while (--i >= 0) {
+		free_masks(irq_desc + i);
+		free_percpu(irq_desc[i].kstat_irqs);
+	}
+
+	return ret;
 }
 
 struct irq_desc *irq_to_desc(unsigned int irq)
-- 
2.27.0