[PATCH v7 3/5] PCI/ASPM: Add and use helper pcie_aspm_get_link

[Heiner Kallweit <hkallweit1@gmail.com>]

Factor out getting the link associated with a pci_dev and use this
helper where appropriate. In addition this helper will be used
in a subsequent patch of this series.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v7:
- add as separate patch
---
 drivers/pci/pcie/aspm.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 574f822bf..91cfea673 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1066,19 +1066,28 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
 	up_read(&pci_bus_sem);
 }
 
+static struct pcie_link_state *pcie_aspm_get_link(struct pci_dev *pdev)
+{
+	struct pci_dev *upstream;
+
+	if (pcie_downstream_port(pdev))
+		upstream = pdev;
+	else
+		upstream = pci_upstream_bridge(pdev);
+
+	return upstream ? upstream->link_state : NULL;
+}
+
 static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 {
-	struct pci_dev *parent = pdev->bus->self;
 	struct pcie_link_state *link;
 
 	if (!pci_is_pcie(pdev))
 		return 0;
 
-	if (pcie_downstream_port(pdev))
-		parent = pdev;
-	if (!parent || !parent->link_state)
+	link = pcie_aspm_get_link(pdev);
+	if (!link)
 		return -EINVAL;
-
 	/*
 	 * A driver requested that ASPM be disabled on this device, but
 	 * if we don't have permission to manage ASPM (e.g., on ACPI
@@ -1095,7 +1104,6 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 	if (sem)
 		down_read(&pci_bus_sem);
 	mutex_lock(&aspm_lock);
-	link = parent->link_state;
 	if (state & PCIE_LINK_STATE_L0S)
 		link->aspm_disable |= ASPM_STATE_L0S;
 	if (state & PCIE_LINK_STATE_L1)
@@ -1188,14 +1196,14 @@ module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
  */
 bool pcie_aspm_enabled(struct pci_dev *pdev)
 {
-	struct pci_dev *bridge = pci_upstream_bridge(pdev);
+	struct pcie_link_state *link = pcie_aspm_get_link(pdev);
 	bool ret;
 
-	if (!bridge)
+	if (!link)
 		return false;
 
 	mutex_lock(&aspm_lock);
-	ret = bridge->link_state ? !!bridge->link_state->aspm_enabled : false;
+	ret = link->aspm_enabled;
 	mutex_unlock(&aspm_lock);
 
 	return ret;
-- 
2.23.0