[PATCH 1/2] PCI: Export pci_parent_bus_reset() for drivers to use

From: Maciej W. Rozycki
Date: Tue Jun 20 2023 - 05:52:17 EST


Export pci_parent_bus_reset() so that drivers do not duplicate it.
Document the interface.

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
---
drivers/pci/pci.c | 15 ++++++++++++++-
include/linux/pci.h | 1 +
2 files changed, 15 insertions(+), 1 deletion(-)

linux-pci-parent-bus-reset-export.diff
Index: linux-macro/drivers/pci/pci.c
===================================================================
--- linux-macro.orig/drivers/pci/pci.c
+++ linux-macro/drivers/pci/pci.c
@@ -5149,7 +5149,19 @@ int pci_bridge_secondary_bus_reset(struc
}
EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset);

-static int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
+/**
+ * pci_parent_bus_reset - Reset a device via its upstream PCI bridge
+ * @dev: Device to reset.
+ * @probe: Only check if reset is possible if TRUE, actually reset if FALSE.
+ *
+ * Perform a device reset by requesting a secondary bus reset via the
+ * device's immediate upstream PCI bridge. Return 0 if successful or
+ * -ENOTTY if the reset failed or it could not have been issued in the
+ * first place because the device is not on a secondary bus of any PCI
+ * bridge or it wouldn't be the only device reset. If probing, then
+ * only verify whether it would be possible to issue a reset.
+ */
+int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
{
struct pci_dev *pdev;

@@ -5166,6 +5178,7 @@ static int pci_parent_bus_reset(struct p

return pci_bridge_secondary_bus_reset(dev->bus->self);
}
+EXPORT_SYMBOL_GPL(pci_parent_bus_reset);

static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, bool probe)
{
Index: linux-macro/include/linux/pci.h
===================================================================
--- linux-macro.orig/include/linux/pci.h
+++ linux-macro/include/linux/pci.h
@@ -1447,6 +1447,7 @@ int devm_request_pci_bus_resources(struc

/* Temporary until new and working PCI SBR API in place */
int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
+int pci_parent_bus_reset(struct pci_dev *dev, bool probe);

#define __pci_bus_for_each_res0(bus, res, ...) \
for (unsigned int __b = 0; \