[PATCH 6/7] irqchip/partition-percpu: Allow chained_desc to be NULL

From: Marc Zyngier
Date: Tue Apr 24 2018 - 10:37:48 EST


As we're about to delay the binding of the partionned interrupt
to the underlying irqchip, we can end-up in a situation where
chained_desc will be NULL, and the operation cannot be carried
out.

Let's make sure we don't explode if that happens.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/irqchip/irq-partition-percpu.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-partition-percpu.c b/drivers/irqchip/irq-partition-percpu.c
index be0df6e0add9..79a1ef0c0f73 100644
--- a/drivers/irqchip/irq-partition-percpu.c
+++ b/drivers/irqchip/irq-partition-percpu.c
@@ -33,6 +33,18 @@ struct partition_desc {
struct irq_domain_ops ops;
};

+static struct irq_data *partition_get_irqd_chip(struct partition_desc *part,
+ struct irq_chip **chip)
+{
+ if (part->chained_desc) {
+ *chip = irq_desc_get_chip(part->chained_desc);
+ return irq_desc_get_irq_data(part->chained_desc);
+ }
+
+ *chip = NULL;
+ return NULL;
+}
+
static bool partition_check_cpu(struct partition_desc *part,
unsigned int cpu, unsigned int hwirq)
{
@@ -45,9 +57,9 @@ static bool partition_check_cpu(struct partition_desc *part,
struct irq_data *data; \
\
part = irq_data_get_irq_chip_data(d); \
- chip = irq_desc_get_chip(part->chained_desc); \
- data = irq_desc_get_irq_data(part->chained_desc); \
- if (partition_check_cpu(part, smp_processor_id(), d->hwirq) && \
+ data = partition_get_irqd_chip(part, &chip); \
+ if (data && \
+ partition_check_cpu(part, smp_processor_id(), d->hwirq) && \
chip->method)

#define PART_CALL_METHOD_VOID(method, d, ...) \
@@ -96,10 +108,12 @@ static int partition_irq_set_type(struct irq_data *d, unsigned int type)
static void partition_irq_print_chip(struct irq_data *d, struct seq_file *p)
{
struct partition_desc *part = irq_data_get_irq_chip_data(d);
- struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
- struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
+ struct irq_chip *chip;
+ struct irq_data *data;

- seq_printf(p, " %5s-%lu", chip->name, data->hwirq);
+ data = partition_get_irqd_chip(part, &chip);
+ if (data)
+ seq_printf(p, " %5s-%lu", chip->name, data->hwirq);
}

static struct irq_chip partition_irq_chip = {
--
2.14.2