[PATCH 5.10 081/545] genirq: Dont return error on missing optional irq_request_resources()

[Greg Kroah-Hartman]

From: Antonio Borneo <antonio.borneo@xxxxxxxxxxx>

[ Upstream commit 95001b756467ecc9f5973eb5e74e97699d9bbdf1 ]

Function irq_chip::irq_request_resources() is reported as optional
in the declaration of struct irq_chip.
If the parent irq_chip does not implement it, we should ignore it
and return.

Don't return error if the functions is missing.

Signed-off-by: Antonio Borneo <antonio.borneo@xxxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220512160544.13561-1-antonio.borneo@xxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 kernel/irq/chip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 0b70811fd956..621d8dd157bc 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1543,7 +1543,8 @@ int irq_chip_request_resources_parent(struct irq_data *data)
 	if (data->chip->irq_request_resources)
 		return data->chip->irq_request_resources(data);
 
-	return -ENOSYS;
+	/* no error on missing optional irq_chip::irq_request_resources */
+	return 0;
 }
 EXPORT_SYMBOL_GPL(irq_chip_request_resources_parent);
 
-- 
2.35.1