[PATCH v6 6/7] PCI: Expose reset type to users of pci_reset_bus()

[Sinan Kaya <okaya@kernel.org>]

Looking to have more control between the users of the API vs. what the API
can do internally. The new reset_type tells the PCI core about the bounds
of the request.

pci_reset_bus() calls different slot reset mechanisms based on given mask.
Slot based reset is prioritized over bus reset.

Users are expected to use PCI_RESET_SLOT mask by default.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
---
 drivers/pci/pci.c           | 12 +++++++++---
 drivers/vfio/pci/vfio_pci.c |  6 ++++--
 include/linux/pci.h         |  2 +-
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a1a7dd6988be..1feecbb7f85d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5236,13 +5236,19 @@ static int __pci_reset_bus(struct pci_bus *bus)
 /**
  * pci_reset_bus - Try to reset a PCI bus
  * @pdev: top level PCI device to reset via slot/bus
+ * @reset_type: resets to try
  *
  * Same as above except return -EAGAIN if the bus cannot be locked
  */
-int pci_reset_bus(struct pci_dev *pdev)
+int pci_reset_bus(struct pci_dev *pdev, u32 reset_type)
 {
-	return (!pci_probe_reset_slot(pdev->slot)) ?
-	    __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus);
+	if ((reset_type & PCI_RESET_SLOT) && !pci_probe_reset_slot(pdev->slot))
+		return __pci_reset_slot(pdev->slot);
+
+	if ((reset_type & PCI_RESET_BUS) && !pci_probe_reset_bus(pdev->bus))
+		return __pci_reset_bus(pdev->bus);
+
+	return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(pci_reset_bus);
 
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index fe7ada997c51..0e80c72b1eaa 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1015,7 +1015,8 @@ static long vfio_pci_ioctl(void *device_data,
 						    &info, slot);
 		if (!ret)
 			/* User has access, do the reset */
-			ret = pci_reset_bus(vdev->pdev);
+			ret = pci_reset_bus(vdev->pdev,
+				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
 
 hot_reset_release:
 		for (i--; i >= 0; i--)
@@ -1390,7 +1391,8 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 	}
 
 	if (needs_reset)
-		ret = pci_reset_bus(vdev->pdev);
+		ret = pci_reset_bus(vdev->pdev,
+				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
 
 put_devs:
 	for (i = 0; i < devs.cur_index; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cde63e0a85ea..8ee4e3c177fe 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1173,7 +1173,7 @@ int pci_reset_function_locked(struct pci_dev *dev, u32 reset_type);
 int pci_try_reset_function(struct pci_dev *dev, u32 reset_type);
 int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
-int pci_reset_bus(struct pci_dev *dev);
+int pci_reset_bus(struct pci_dev *dev, u32 reset_type);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
-- 
2.19.0