[PATCH 4.20 33/57] ACPI/IORT: Fix rc_dma_get_range()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>

commit c7777236dd8f587f6a8d6800c03df318fd4d2627 upstream.

When executed for a PCI_ROOT_COMPLEX type, iort_match_node_callback()
expects the opaque pointer argument to be a PCI bus device. At the
moment rc_dma_get_range() passes the PCI endpoint instead of the bus,
and we've been lucky to have pci_domain_nr(ptr) return 0 instead of
crashing. Pass the bus device to iort_scan_node().

Fixes: 5ac65e8c8941 ("ACPI/IORT: Support address size limit for root complexes")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Cc: stable@vger.kernel.org
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/arm64/iort.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -951,9 +951,10 @@ static int rc_dma_get_range(struct devic
 {
 	struct acpi_iort_node *node;
 	struct acpi_iort_root_complex *rc;
+	struct pci_bus *pbus = to_pci_dev(dev)->bus;
 
 	node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
-			      iort_match_node_callback, dev);
+			      iort_match_node_callback, &pbus->dev);
 	if (!node || node->revision < 1)
 		return -ENODEV;