tpm: fix the rollback in tpm_chip_register()

commit 72c91ce8 upstream.

Fixed the rollback and gave more self-documenting names for the
functions.

Fixes: d972b052 ("tpm: fix call order in tpm-chip.c")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/char/tpm/tpm-chip.c

@@ -137,7 +137,7 @@ struct tpm_chip *tpmm_chip_alloc(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
 
-static int tpm_dev_add_device(struct tpm_chip *chip)
+static int tpm_add_char_device(struct tpm_chip *chip)
 {
 	int rc;
 
@@ -148,7 +148,6 @@ static int tpm_dev_add_device(struct tpm_chip *chip)
 			chip->devname, MAJOR(chip->dev.devt),
 			MINOR(chip->dev.devt), rc);
 
-		device_unregister(&chip->dev);
 		return rc;
 	}
 
@@ -159,13 +158,14 @@ static int tpm_dev_add_device(struct tpm_chip *chip)
 			chip->devname, MAJOR(chip->dev.devt),
 			MINOR(chip->dev.devt), rc);
 
+		cdev_del(&chip->cdev);
 		return rc;
 	}
 
 	return rc;
 }
 
-static void tpm_dev_del_device(struct tpm_chip *chip)
+static void tpm_del_char_device(struct tpm_chip *chip)
 {
 	cdev_del(&chip->cdev);
 	device_unregister(&chip->dev);
@@ -225,7 +225,7 @@ int tpm_chip_register(struct tpm_chip *chip)
 	if (rc)
 		return rc;
 
-	rc = tpm_dev_add_device(chip);
+	rc = tpm_add_char_device(chip);
 	if (rc)
 		goto out_err;
 
@@ -264,6 +264,6 @@ void tpm_chip_unregister(struct tpm_chip *chip)
 	synchronize_rcu();
 
 	tpm1_chip_unregister(chip);
-	tpm_dev_del_device(chip);
+	tpm_del_char_device(chip);
 }
 EXPORT_SYMBOL_GPL(tpm_chip_unregister);