[PATCH v2 1/2] PCI: Export pci_parent_bus_reset() for drivers to use

[Maciej W. Rozycki]

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

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
---
Changes from v1, 
<https://lore.kernel.org/r/alpine.DEB.2.21.2306200231020.14084@xxxxxxxxxxxxxxxxx/>:

- Reword function description so as to list the return values separately.
---
 drivers/pci/pci.c   |   17 ++++++++++++++++-
 include/linux/pci.h |    1 +
 2 files changed, 17 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
@@ -4833,7 +4833,21 @@ 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 failure 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.
+ *
+ * Returns: 0 if successful or -ENOTTY otherwise.
+ */
+int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
 {
 	struct pci_dev *pdev;
 
@@ -4850,6 +4864,7 @@ 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
@@ -1595,6 +1595,7 @@ 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;					\