From: Aaron Ma <aaron...@canonical.com>

[ Upstream commit bb6bccba390c7d743c1e4427de4ef284c8cc6869 ]

Add a non-NULL check to fix potential NULL pointer dereference
Cleanup code to call function once.

Signed-off-by: Aaron Ma <aaron...@canonical.com>
Fixes: 2bf9a0a12749b ('iommu/amd: Add iommu support for ACPI HID devices')
Signed-off-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/iommu/amd_iommu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 1f2ed44de2438..fe18804a50083 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -139,10 +139,14 @@ static struct lock_class_key reserved_rbtree_key;
 static inline int match_hid_uid(struct device *dev,
                                struct acpihid_map_entry *entry)
 {
+       struct acpi_device *adev = ACPI_COMPANION(dev);
        const char *hid, *uid;
 
-       hid = acpi_device_hid(ACPI_COMPANION(dev));
-       uid = acpi_device_uid(ACPI_COMPANION(dev));
+       if (!adev)
+               return -ENODEV;
+
+       hid = acpi_device_hid(adev);
+       uid = acpi_device_uid(adev);
 
        if (!hid || !(*hid))
                return -ENODEV;
-- 
2.20.1

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