Setiap bus PCI pada sistem direpresentasikan dengan struktur data  pci_bus

struct pci_bus {
  struct pci_bus  *parent;     /* parent bus this bridge is on */
  struct pci_bus  *children;   /* chain of P2P bridges on this bus */
  struct pci_bus  *next;       /* chain of all PCI buses */

  struct pci_dev  *self;       /* bridge device as seen by parent */
  struct pci_dev  *devices;    /* devices behind this bridge */

  void    *sysdata;            /* hook for sys-specific extension */

  unsigned char  number;       /* bus number */
  unsigned char  primary;      /* number of primary bridge */
  unsigned char  secondary;    /* number of secondary bridge */
  unsigned char  subordinate;  /* max number of subordinate buses */
};

Sumber : tldp.org