[PATCH 04/12] ACPI/IORT: Remove useless PCI bus walk

Lorenzo Pieralisi lorenzo.pieralisi at arm.com
Thu May 21 13:00:00 UTC 2020

The PCI bus domain number (used in the iort_match_node_callback() -
pci_domain_nr() call) is cascaded through the PCI bus hierarchy at PCI
bus enumeration time, therefore there is no need in iort_find_dev_node()
to walk the PCI bus upwards to grab the root bus to be passed to
iort_scan_node(), the device->bus PCI bus pointer will do.

Remove this useless code.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Hanjun Guo <guohanjun at huawei.com>
Cc: Sudeep Holla <sudeep.holla at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Robin Murphy <robin.murphy at arm.com>
Cc: "Rafael J. Wysocki" <rjw at rjwysocki.net>
 drivers/acpi/arm64/iort.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index f346a785e0b5..ae9e1089d954 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -575,10 +575,7 @@ static struct acpi_iort_node *iort_find_dev_node(struct device *dev)
 				      iort_match_node_callback, dev);
-	/* Find a PCI root bus */
 	pbus = to_pci_dev(dev)->bus;
-	while (!pci_is_root_bus(pbus))
-		pbus = pbus->parent;
 	return iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
 			      iort_match_node_callback, &pbus->dev);

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