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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Antonio Borneo <antonio.borneo@foss.st.com>,
        Marc Zyngier <maz@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 118/779] genirq: Dont return error on missing optional irq_request_resources()
Date:   Mon, 15 Aug 2022 19:56:02 +0200
Message-Id: <20220815180342.371126246@linuxfoundation.org>
In-Reply-To: <20220815180337.130757997@linuxfoundation.org>
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From: Antonio Borneo <antonio.borneo@foss.st.com>

[ 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@foss.st.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220512160544.13561-1-antonio.borneo@foss.st.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 a98bcfc4be7b..f3920374f71c 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1516,7 +1516,8 @@ 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