linux-kernel - [PATCH 2/2] iommu/arm-smmu: fix -Wunused-const-variable warning

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Date:   Tue, 24 Dec 2019 17:15:00 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] iommu/arm-smmu: fix -Wunused-const-variable warning

For ARCH=arm builds, OF is not necessarily enabled, that is, you can
build this driver without CONFIG_OF.

When CONFIG_OF is unset, of_match_ptr() is NULL, and arm_smmu_of_match
is left orphan.

Building it with W=1 emits a warning:

drivers/iommu/arm-smmu.c:1904:34: warning: ‘arm_smmu_of_match’ defined but not used [-Wunused-const-variable=]
 static const struct of_device_id arm_smmu_of_match[] = {
                                  ^~~~~~~~~~~~~~~~~

There are two ways to fix this:

 - annotate arm_smmu_of_match with __maybe_unused (or surround the
   code with #ifdef CONFIG_OF ... #endif)

 - stop using of_match_ptr()

This commit took the latter solution.

It slightly increases the object size, but it is probably not a big deal
because arm_smmu_device_dt_probe() is also compiled irrespective of
CONFIG_OF.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 drivers/iommu/arm-smmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 4f1a350d9529..0446a3bf6bd0 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -2267,7 +2267,7 @@ static const struct dev_pm_ops arm_smmu_pm_ops = {
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
 		.name			= "arm-smmu",
-		.of_match_table		= of_match_ptr(arm_smmu_of_match),
+		.of_match_table		= arm_smmu_of_match,
 		.pm			= &arm_smmu_pm_ops,
 		.suppress_bind_attrs	= true,
 	},
-- 
2.17.1