如何从struct pci_dev获取总线/设备/号码？

Question

https://elixir.bootlin.com/linux/latest/source/include/linux/pci.h#L286

In

struct pci_dev,

I can only see bus and function:

struct pci_bus  *bus;   

and

unsigned int    devfn;  

seems no device (of B/D/F) information?

and

struct pci_slot *slot;

In my test, the *slot point to NULL, why ?

Answer 1

I found:

device = PCI_SLOT(pdev->devfn);
fn =  PCI_FUNC(pdev->devfn);

https://elixir.bootlin.com/linux/v3.5/source/include/linux/pci.h#L31

Answer 2

Devfn contains the device number in bits 7:3 and the function number in bits 2:0. The bus number is in bus->number. So the BDF is

    bus->number << 8 | devfn

I don't know about slot; perhaps the device you are looking at is an integrated device?