On 9/21/17 3:43 PM, Bjorn Helgaas wrote:

On Mon, Sep 18, 2017 at 02:26:49PM -0500, Bryant G. Ly wrote:

quoted

When enabling SR-IOV one might want to have their
own version of starting device drivers for the VFs.
This patch allows for SR-IOV callers to use
pci_bus_add_virtfn_device instead of generic
pci_bus_add_device.

When enabling SR-IOV in PSeries architecture the
dynamic VFs created within the sriov_configure sysfs call
will not load the device driver as firmware will load
the device node when the VF device is assigned to the
logical partition. So we needed a way to overwrite the
way device driver matching is done for virtual functions
on powervm.

Signed-off-by: Bryant G. Ly <redacted>
Signed-off-by: Juan J. Alvarez <redacted>
---
  drivers/pci/bus.c   | 51 ++++++++++++++++++++++++++++++++++++++++++---------
  drivers/pci/iov.c   |  2 +-
  include/linux/pci.h |  3 +++
  3 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index bc56cf19afd3..86daf62c4048 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c

@@ -302,16 +302,9 @@ void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
  
  void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
  
-/**
- * pci_bus_add_device - start driver for a single device
- * @dev: device to add
- *
- * This adds add sysfs entries and start device drivers
- */
-void pci_bus_add_device(struct pci_dev *dev)
-{
-	int retval;
  
+void pci_bus_add_sysfs_entries(struct pci_dev *dev)
+{
  	/*
  	 * Can not put in pci_device_add yet because resources
  	 * are not assigned yet for some devices.

@@ -321,6 +314,11 @@ void pci_bus_add_device(struct pci_dev *dev)
  	pci_create_sysfs_dev_files(dev);
  	pci_proc_attach_device(dev);
  	pci_bridge_d3_update(dev);
+}
+
+void pci_bus_match_device_driver(struct pci_dev *dev)
+{
+	int retval;
  
  	dev->match_driver = true;
  	retval = device_attach(&dev->dev);

@@ -333,6 +331,41 @@ void pci_bus_add_device(struct pci_dev *dev)
  
  	dev->is_added = 1;
  }
+
+#ifdef CONFIG_PCI_IOV
+void __weak pci_bus_match_virtfn_driver(struct pci_dev *dev)
+{
+	pci_bus_match_device_driver(dev);
+}
+
+/**
+ * pci_bus_add_virtfn_device - start driver for a virtual function device
+ * @dev: device to add
+ *
+ * This adds add sysfs entries and start device drivers for
+ * virtual function devices
+ *
+ */
+void pci_bus_add_virtfn_device(struct pci_dev *pdev)
+{
+	pci_bus_add_sysfs_entries(pdev);
+	pci_bus_match_virtfn_driver(pdev);
+}
+EXPORT_SYMBOL_GPL(pci_bus_add_virtfn_device);

Is there any way we can avoid adding this new interface?  I don't
really want a new global exported symbol just to support this highly
platform-specific functionality.

If we could figure out a way to set dev->match_driver to false instead
of true in pci_bus_add_device(), it *looks* like that would be enough
to accomplish what you need.  Maybe that could be done via a pcibios
hook or a new function pointer in struct pci_host_bridge, similar to
the swizzle_irq pointer?

Yes! I will remove the first two patches in the series and only utilize the third
patch but addingpdev->match_driver = -1; under pseries_pcibios_bus_add_device, which is 
a new function I added for machine dependent bus add of a device. The 
patch will then require https://patchwork.kernel.org/patch/9882915/ 
which basically allows for match_driver state to not get changed later 
under the pci_bus_match due to allowing for the match_driver to be a int 
vs a bool. I will push up another patch removing the first two patches 
and adding that extra line. -Bryant

quoted

+#endif
+
+/**
+ * pci_bus_add_device - start driver for a single device
+ * @dev: device to add
+ *
+ * This adds add sysfs entries and start device drivers
+ */
+void pci_bus_add_device(struct pci_dev *dev)
+{
+	pci_bus_add_sysfs_entries(dev);
+	pci_bus_match_device_driver(dev);
+}
+
  EXPORT_SYMBOL_GPL(pci_bus_add_device);
  
  /**

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index ac41c8be9200..16cc72545847 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c

@@ -162,7 +162,7 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)
  
  	pci_device_add(virtfn, virtfn->bus);
  
-	pci_bus_add_device(virtfn);
+	pci_bus_add_virtfn_device(virtfn);
  	sprintf(buf, "virtfn%u", id);
  	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
  	if (rc)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index f68c58a93dd0..39f5c0b4bf23 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -911,6 +911,9 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn);
  void pci_device_add(struct pci_dev *dev, struct pci_bus *bus);
  unsigned int pci_scan_child_bus(struct pci_bus *bus);
  void pci_bus_add_device(struct pci_dev *dev);
+#ifdef CONFIG_PCI_IOV
+void pci_bus_add_virtfn_device(struct pci_dev *dev);
+#endif
  void pci_read_bridge_bases(struct pci_bus *child);
  struct resource *pci_find_parent_resource(const struct pci_dev *dev,
  					  struct resource *res);

-- 
2.11.0 (Apple Git-81)