RE: [PATCH v2] PCI: hv: fix pci-hyperv build when SYSFS not enabled

[Haiyang Zhang]

> -----Original Message-----
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Sent: Wednesday, July 3, 2019 12:59 PM
> To: LKML <linux-kernel@xxxxxxxxxxxxxxx>; linux-pci <linux-
> pci@xxxxxxxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>; Jake Oshins
> <jakeo@xxxxxxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang
> Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; Sasha Levin <sashal@xxxxxxxxxx>; Bjorn
> Helgaas <bhelgaas@xxxxxxxxxx>; linux-hyperv@xxxxxxxxxxxxxxx; Dexuan
> Cui <decui@xxxxxxxxxxxxx>; Yuehaibing <yuehaibing@xxxxxxxxxx>
> Subject: [PATCH v2] PCI: hv: fix pci-hyperv build when SYSFS not enabled
> 
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> 
> Fix build of drivers/pci/controller/pci-hyperv.o when
> CONFIG_SYSFS is not set/enabled by adding stubs for
> pci_create_slot() and pci_destroy_slot().
> 
> Fixes these build errors:
> 
> ERROR: "pci_destroy_slot" [drivers/pci/controller/pci-hyperv.ko] undefined!
> ERROR: "pci_create_slot" [drivers/pci/controller/pci-hyperv.ko] undefined!
> 
> Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot
> information")
> 
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: Jake Oshins <jakeo@xxxxxxxxxxxxx>
> Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> Cc: Sasha Levin <sashal@xxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx
> Cc: linux-hyperv@xxxxxxxxxxxxxxx
> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: Yuehaibing <yuehaibing@xxxxxxxxxx>
> ---
> v2:
> - provide non-CONFIG_SYSFS stubs for pci_create_slot() and
>   pci_destroy_slot() [suggested by Matthew Wilcox <willy@xxxxxxxxxxxxx>]
> - use the correct Fixes: tag [Dexuan Cui <decui@xxxxxxxxxxxxx>]
> 
>  include/linux/pci.h |   12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> --- lnx-52-rc7.orig/include/linux/pci.h
> +++ lnx-52-rc7/include/linux/pci.h
> @@ -25,6 +25,7 @@
>  #include <linux/ioport.h>
>  #include <linux/list.h>
>  #include <linux/compiler.h>
> +#include <linux/err.h>
>  #include <linux/errno.h>
>  #include <linux/kobject.h>
>  #include <linux/atomic.h>
> @@ -947,14 +948,21 @@ int pci_scan_root_bus_bridge(struct pci_
>  struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev
> *dev,
>  				int busnr);
>  void pcie_update_link_speed(struct pci_bus *bus, u16 link_status);
> +#ifdef CONFIG_SYSFS
> +void pci_dev_assign_slot(struct pci_dev *dev);
>  struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
>  				 const char *name,
>  				 struct hotplug_slot *hotplug);
>  void pci_destroy_slot(struct pci_slot *slot);
> -#ifdef CONFIG_SYSFS
> -void pci_dev_assign_slot(struct pci_dev *dev);
>  #else
>  static inline void pci_dev_assign_slot(struct pci_dev *dev) { }
> +static inline struct pci_slot *pci_create_slot(struct pci_bus *parent,
> +					       int slot_nr,
> +					       const char *name,
> +					       struct hotplug_slot *hotplug) {
> +	return ERR_PTR(-EINVAL);
> +}
> +static inline void pci_destroy_slot(struct pci_slot *slot) { }
>  #endif
>  int pci_scan_slot(struct pci_bus *bus, int devfn);
>  struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn);
> 

The serial number in slot info is used to match VF NIC with Synthetic NIC.
Without selecting SYSFS, the SRIOV feature will fail on VM on Hyper-V and
Azure. The first version of this patch should be used.

@Stephen Hemminger how do you think?

Thanks,
- Haiyang