[net-next PATCH 0/3] Retrieve number of VFs in a bus-agnostic way

[net-next PATCH 0/3] Retrieve number of VFs in a bus-agnostic way

[Phil Sutter]

Previously, it was assumed that only PCI NICs would be capable of having
virtual functions - with my proposed enhancement of dummy NIC driver
implementing (fake) ones for testing purposes, this is no longer true.

Discussion of said patch has led to the suggestion of implementing a
bus-agnostic method for VF count retrieval so rtnetlink could work with
both real VF-capable PCI NICs as well as my dummy modifications without
introducing ugly hacks.

The following series tries to achieve just that by introducing a bus
type callback to retrieve a device's number of VFs, implementing this
callback for PCI bus and finally adjusting rtnetlink to make use of the
generalized infrastructure.

Phil Sutter (3):
  device: bus_type: Introduce num_vf callback
  PCI: implement num_vf bus type callback
  device: Implement a bus agnostic dev_num_vf routine

 drivers/pci/pci-driver.c |  6 ++++++
 include/linux/device.h   | 11 +++++++++++
 include/linux/pci.h      |  2 --
 net/core/rtnetlink.c     |  3 +--
 4 files changed, 18 insertions(+), 4 deletions(-)

-- 
2.11.0

[net-next PATCH 1/3] device: bus_type: Introduce num_vf callback

[Phil Sutter]

This allows for bus types to implement their own method of retrieving
the number of virtual functions a NIC on that type of bus supports.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/linux/device.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/device.h b/include/linux/device.h
index 491b4c0ca6333..6d73b70a4a5d7 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -88,6 +88,8 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
  *
  * @suspend:	Called when a device on this bus wants to go to sleep mode.
  * @resume:	Called to bring a device on this bus out of sleep mode.
+ * @num_vf:	Called to find out how many virtual functions a device on this
+ *		bus supports.
  * @pm:		Power management operations of this bus, callback the specific
  *		device driver's pm-ops.
  * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
@@ -127,6 +129,8 @@ struct bus_type {
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
 
+	int (*num_vf)(struct device *dev);
+
 	const struct dev_pm_ops *pm;
 
 	const struct iommu_ops *iommu_ops;
-- 
2.11.0

[net-next PATCH 2/3] PCI: implement num_vf bus type callback

[Phil Sutter]

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 drivers/pci/pci-driver.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 1ccce1cd6aca4..63d8e18fb6b14 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1432,6 +1432,11 @@ static int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static int pci_bus_num_vf(struct device *dev)
+{
+	return pci_num_vf(to_pci_dev(dev));
+}
+
 struct bus_type pci_bus_type = {
 	.name		= "pci",
 	.match		= pci_bus_match,
@@ -1443,6 +1448,7 @@ struct bus_type pci_bus_type = {
 	.bus_groups	= pci_bus_groups,
 	.drv_groups	= pci_drv_groups,
 	.pm		= PCI_PM_OPS_PTR,
+	.num_vf		= pci_bus_num_vf,
 };
 EXPORT_SYMBOL(pci_bus_type);
 
-- 
2.11.0

[net-next PATCH 3/3] device: Implement a bus agnostic dev_num_vf routine

[Phil Sutter]

Now that pci_bus_type has num_vf callback set, dev_num_vf can be
implemented in a bus type independent way and the check for whether a
PCI device is being handled in rtnetlink can be dropped.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/linux/device.h | 7 +++++++
 include/linux/pci.h    | 2 --
 net/core/rtnetlink.c   | 3 +--
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 6d73b70a4a5d7..bd684fc8ec1d8 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1144,6 +1144,13 @@ extern int device_online(struct device *dev);
 extern void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
 extern void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
 
+static inline int dev_num_vf(struct device *dev)
+{
+	if (dev->bus && dev->bus->num_vf)
+		return dev->bus->num_vf(dev);
+	return 0;
+}
+
 /*
  * Root device objects for grouping under /sys/devices
  */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e2d1a124216a9..adbc859fe7c4c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -885,7 +885,6 @@ void pcibios_setup_bridge(struct pci_bus *bus, unsigned long type);
 void pci_sort_breadthfirst(void);
 #define dev_is_pci(d) ((d)->bus == &pci_bus_type)
 #define dev_is_pf(d) ((dev_is_pci(d) ? to_pci_dev(d)->is_physfn : false))
-#define dev_num_vf(d) ((dev_is_pci(d) ? pci_num_vf(to_pci_dev(d)) : 0))
 
 /* Generic PCI functions exported to card drivers */
 
@@ -1630,7 +1629,6 @@ static inline int pci_get_new_domain_nr(void) { return -ENOSYS; }
 
 #define dev_is_pci(d) (false)
 #define dev_is_pf(d) (false)
-#define dev_num_vf(d) (0)
 #endif /* CONFIG_PCI */
 
 /* Include architecture-dependent settings and functions */
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 75e3ea7bda08f..94dd6d53ea9a5 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -837,8 +837,7 @@ static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
 static inline int rtnl_vfinfo_size(const struct net_device *dev,
 				   u32 ext_filter_mask)
 {
-	if (dev->dev.parent && dev_is_pci(dev->dev.parent) &&
-	    (ext_filter_mask & RTEXT_FILTER_VF)) {
+	if (dev->dev.parent && (ext_filter_mask & RTEXT_FILTER_VF)) {
 		int num_vfs = dev_num_vf(dev->dev.parent);
 		size_t size = nla_total_size(0);
 		size += num_vfs *
-- 
2.11.0

Re: [net-next PATCH 0/3] Retrieve number of VFs in a bus-agnostic way

[David Miller]

From: Phil Sutter <phil@nwl.cc>
Date: Wed, 18 Jan 2017 14:04:36 +0100

> Previously, it was assumed that only PCI NICs would be capable of having
> virtual functions - with my proposed enhancement of dummy NIC driver
> implementing (fake) ones for testing purposes, this is no longer true.
> 
> Discussion of said patch has led to the suggestion of implementing a
> bus-agnostic method for VF count retrieval so rtnetlink could work with
> both real VF-capable PCI NICs as well as my dummy modifications without
> introducing ugly hacks.
> 
> The following series tries to achieve just that by introducing a bus
> type callback to retrieve a device's number of VFs, implementing this
> callback for PCI bus and finally adjusting rtnetlink to make use of the
> generalized infrastructure.

This is really nice and clean, compare it to your original approach :-)

Series applied, thanks!

Re: [net-next PATCH 0/3] Retrieve number of VFs in a bus-agnostic way

[Phil Sutter]

On Fri, Jan 20, 2017 at 11:43:46AM -0500, David Miller wrote:
> From: Phil Sutter <phil@nwl.cc>
> Date: Wed, 18 Jan 2017 14:04:36 +0100
> 
> > Previously, it was assumed that only PCI NICs would be capable of having
> > virtual functions - with my proposed enhancement of dummy NIC driver
> > implementing (fake) ones for testing purposes, this is no longer true.
> > 
> > Discussion of said patch has led to the suggestion of implementing a
> > bus-agnostic method for VF count retrieval so rtnetlink could work with
> > both real VF-capable PCI NICs as well as my dummy modifications without
> > introducing ugly hacks.
> > 
> > The following series tries to achieve just that by introducing a bus
> > type callback to retrieve a device's number of VFs, implementing this
> > callback for PCI bus and finally adjusting rtnetlink to make use of the
> > generalized infrastructure.
> 
> This is really nice and clean, compare it to your original approach :-)

Yes, indeed! Thanks a lot for pointing me into the right direction. :)

Cheers, Phil