Linux PCIe Driver: What to use for private data structure? -

i'm creating first pcie driver linux , have question regarding structure use pci_set_drvdata() function.

the pcie hardware built in house , using dma send data , device. not sound card or other subsystem needs plugged kernel.

when @ examples there seems specific struct fill in , send pci_set_drvdata().

what fill in case? ignore , send in blank structure? line referring in pcie driver is:

struct structure_in_question *my_struct; my_struct = kzalloc( sizeof(*my_struct), gfp_kernel) ); 

this found in probe() function.

that function used associating device private data cannot supplied other way. if there no such data function should not used.