From: YueHaibing <yuehaibing@xxxxxxxxxx> Sent: Friday, May 31, 2019 8:09 AM > > while building without CONFIG_SYSFS, fails as below: > > drivers/pci/controller/pci-hyperv.o: In function 'hv_pci_assign_slots': > pci-hyperv.c:(.text+0x40a): undefined reference to 'pci_create_slot' > drivers/pci/controller/pci-hyperv.o: In function 'pci_devices_present_work': > pci-hyperv.c:(.text+0xc02): undefined reference to 'pci_destroy_slot' > drivers/pci/controller/pci-hyperv.o: In function 'hv_pci_remove': > pci-hyperv.c:(.text+0xe50): undefined reference to 'pci_destroy_slot' > drivers/pci/controller/pci-hyperv.o: In function 'hv_eject_device_work': > pci-hyperv.c:(.text+0x11f9): undefined reference to 'pci_destroy_slot' > > Select SYSFS while PCI_HYPERV is set to fix this. > I'm wondering if is the right way to fix the problem. Conceptually is it possible to setup & operate virtual PCI devices like pci-hyperv.c does, even if sysfs is not present? Or is it right to always required sysfs? The function pci_dev_assign_slot() in slot.c has a null implementation in include/linux/pci.h when CONFIG_SYSFS is not defined, which seems to be trying to solve the same problem for that function. And if CONFIG_HOTPLUG_PCI is defined but CONFIG_SYSFS is not, pci_hp_create_module_link() and pci_hp_remove_module_link() look like they would have the same problem. Maybe there should be degenerate implementations of pci_create_slot() and pci_destroy_slot() for cases when CONFIG_SYSFS is not defined? But I'll admit I don't know the full story behind how PCI slots are represented and used, so maybe I'm off base. I just noticed the inconsistency in how other functions in slot.c are handled. Thoughts? Michael
