On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) > +{ > + int rc; > + > + device_initialize(&chip->devs); > + chip->devs.parent = chip->dev.parent; > + chip->devs.class = tpmrm_class; > + > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > + if (rc) > + goto out_put_devs; > + /* > + * get extra reference on main device to hold on behalf of devs. > + * This holds the chip structure while cdevs is in use. The > + * corresponding put is in the tpm_devs_release. > + */ > + get_device(&chip->dev); > + chip->devs.release = tpm_devs_release; > + chip->devs.devt = > + MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); > + cdev_init(&chip->cdevs, &tpmrm_fops); > + chip->cdevs.owner = THIS_MODULE; > + > + rc = cdev_device_add(&chip->cdevs, &chip->devs); > + if (rc) { > + dev_err(&chip->devs, > + "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n", > + dev_name(&chip->devs), MAJOR(chip->devs.devt), > + MINOR(chip->devs.devt), rc); > + goto out_put_devs; > + } > + > + return 0; > + > +out_put_devs: > + put_device(&chip->devs); I'd rather you organize this so chip->devs.release and the get_device is always sent instead of having the possiblity for a put_device that doesn't call release Jason