taglinefilesource code
upc_bit2672drivers/cdrom/sbpcd.cD_S[d].diskstate_flags &= ~upc_bit;
upc_bit2754drivers/cdrom/sbpcd.cD_S[d].diskstate_flags |= upc_bit;
upc_bit220include/linux/sbpcd.h#define upc_valid    (D_S[d].diskstate_flags&upc_bit)