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* [PATCH v2] iommu/amd: Fix get_acpihid_device_id()
@ 2020-05-11 16:33 ` Raul E Rangel
  0 siblings, 0 replies; 4+ messages in thread
From: Raul E Rangel @ 2020-05-11 16:33 UTC (permalink / raw)
  To: Joerg Roedel, Andy Shevchenko, iommu, linux-acpi
  Cc: evgreen, dianders, Daniel Kurtz, Adrian Hunter, Ulf Hansson,
	Raul E Rangel, Andy Shevchenko, Jerry Snitselaar, Joerg Roedel,
	Mika Westerberg, Rafael J. Wysocki, linux-kernel

acpi_dev_hid_uid_match() expects a null pointer for UID if it doesn't
exist. The acpihid_map_entry contains a char buffer for holding the
UID. If no UID was provided in the IVRS table, this buffer will be
zeroed. If we pass in a null string, acpi_dev_hid_uid_match() will
return false because it will try and match an empty string to the ACPI
UID of the device.

Fixes: ae5e6c6439c3 ("iommu/amd: Switch to use acpi_dev_hid_uid_match()")
Suggested-by: Andy Shevchenko <>
Signed-off-by: Raul E Rangel <>
Reviewed-by: Andy Shevchenko <>

Changes in v2:
- Added Suggested by
- Fixed commit description
- Decided to keep `p->uid[0]` instead of `*p->uid` since the data member is an array instead of a pointer.
- Used clang-format

 drivers/iommu/amd_iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 20cce366e951..06f603366cb1 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -125,7 +125,8 @@ static inline int get_acpihid_device_id(struct device *dev,
 		return -ENODEV;
 	list_for_each_entry(p, &acpihid_map, list) {
-		if (acpi_dev_hid_uid_match(adev, p->hid, p->uid)) {
+		if (acpi_dev_hid_uid_match(adev, p->hid,
+					   p->uid[0] ? p->uid : NULL)) {
 			if (entry)
 				*entry = p;
 			return p->devid;

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-05-13  9:15 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-11 16:33 [PATCH v2] iommu/amd: Fix get_acpihid_device_id() Raul E Rangel
2020-05-11 16:33 ` Raul E Rangel
2020-05-13  9:15 ` Joerg Roedel
2020-05-13  9:15   ` Joerg Roedel

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